A17-1220-1OM-L 180 TEXAS AGRICULTURAL EXPERIMENT STATION AGRICULTURAL AND MECHANICAL COLLEGE 0F TEXAS w. n. BIZZELL, Pleflldélfl BULLETIN NO. 270 _ _ OCTOBER, 1920 DIVISION OF PLANT PATHOLOGY AND PHYSIOLOGY A STUDY OF THE BLACK AND THE YELLOW MOLDS OF EAR CORN B. YOUNGBLOOD, DIRECTOR, COLLEGE STATION, BRAZOS COUNTY, TEXAS STATION STAFFT ADMINISTRATION B. YOUNGBLOOD, M. _S., Director - CHAS. A. FELKER, Chief Clerk A. S. WARE. Secretary _ , A. D. JACKSON, Executive Assistant Cnmuzs SOSOLIK. Technical Asslltdlli VETERINARY SCIENCE ‘M. FRANCIS, D. V. M., Chief H. Scnuinr, D M., Veterinarian D. H. BENNETT, V. M. D., Veterinarian CHEMISTRY G. S. FRAPS, Ph. D., Chief; State Chemist S. E. Asisuiiv, M. S., Assistant Chemist S. Lounmn, B. S., Assistant Chem_ist J. B. Surru, B. S., Assistant Chemist WALDO WALKER, Assistant Chemist HORTICULTURE H. NESS, M. S., Chief W. S. Horcmuss. Horticulturist ANIMAL INDUSTRY J. M. Jonas, A. M., Chief; Sheep and Goat Investigations. J. B. McNULTY, B. S.. Dairgman R. M. SHERWOOD, B. S., Poultryman O. E. MGCONNELL, Animal Husbandman in Charge of Swine Investigations R. A. BREWER, B. S., Assistant Animal Hus- bandman ' ENTOMOLOGY M. c. TANQUARY, Ph. D., Chief; sum Ento mologisi _ ,' H. J. REINHARD, B. S.. Entomologist '; ———-—---——-, Apiculturist _ C. S. Rune, B. S., Assistant Entomologist " “i i AGRONOMY A. B. Cowman, B. S., Chief _ A. H. LEIDIGH, B. S., Agronomist E. W. GEYER, B. S., Agronomist -i—-——., Agroriomist PLANT PATHOLOGY AND PHYSIOLOGY J. J. TAUBENHAUS, Ph. D., Chief FEED CONTROL SERVICE F. D. FULLER, M. S., Chief S. D. PEARCE, Executive .S‘erretary FORESTRY E. O. SIECKB, B. S., Chief; State Forester PLANT BREEDING E. P. HUMBERT, Ph. D., Chief FARM AND RANCH ECONOMICS A. B. Cox, Ph. D., Chief . SOIL SURVEY **W. T. CARTER, JR.. B. S.. Chief T. M. BUSHNELL, B. S., Soil Surveyor H. W. HAWKER, Soil Surveyor SUBSTATIONS No. 1. Beeville, Bee County I. E. COWART, M._S., Superintendent No. 2. Troup, Smith County W. S. Horciixiss, Superintendent No. 3. Angleton, Brazorla County E. B. REYNOLDS, M. S., Superintendent Beaumont, Jefferson County A. H. PRINCE, S., Superintendent 5. Temple, Bell County D. T. KXLLOUGH, B. S., Superintendent No. 6. Danton, Denton County C. H. MCDOWELL, B. S., Superintendent No. 7. Spur, Dickens County B. E. DICKSON, B. S., Superintendent TAs of October 1, 1920. No. 8. Lubbock, Lubbock County R. E. KARPER, B. S., Superintendent No. 9. Pecos, Reeves County V. L. CORY, B. S., Superintendent No. l0. (Feeding and Breeding Substation) College Station, Brazos County L. J. McCALL, Superintendent No. ll. Nacogdoches" Nacogdoches County G. T. McNEss, Superintendent . **No. 12. Chillicothe, Hardeman County B. CRON, B. S., Superintendent V. E. Human, B.- S., Scientific Assistant No. l4. Sonora, Sutton-Edwards Counties E. M. PETERS, B. S., Superintendent *In cooperation with the School of Veterinary Medicine, A. if: M‘. College of Texas. "In cooperation with the United States Department of Agriculture. BULLETIN N0. 2'70 OCTOBER, 1920 A STUDY OF THE BLACK AND THE YELLOW MOLDS OF EAR CORN. BY J. J. TAUBENHAUS. The present bulletin is the result of four years’ careful study- of the black and the yellow molds of ear corn. These studies were undertaken at the insistent request of corn growers in Texas. That these diseases are of considerable economic importance may be seen from the fol- lowing figures. A three-year average of the Texas corn crop for 1917, 1918, and 1919, was estimated by the Monthly Crop Reporter* as 114,566,666, bushels, with an average price of $176,432,666.66. A conservative estimate 0f the average annual loss from the black and the yellow molds of ear corn during that time is 5,718,333 bushels. If the average price for the last three years is taken to be $1.53 per bushel, then the average annual money loss from the ear molds of corn was $8,806,233. Since the black and the yellow molds of ear corn also- attack broom corn, it would 11ot be out of place to carry the figures a step further. A three» year average of the production of broom corn for1917, 1918, and 1919 is figured at 12,800 tons with an average price of $305,933. In estimat- ing the losses from the black and the yellow molds of broom corn at 4 per cent. of the total crop, there will be a loss of 512 tons, worth $12,237. When the average annual loss of broom corn due to the presence of these molds is added to the average annual loss of field corn, from the same cause, it may be asserted that the Texas growers are sustaining a yearly loss of $8,818,349. The thoughtful farmer will at once realize the importance of being able to save this unnecessary waste. It should be added that as far as the corn crop is concerned, the greatest losses are sustained primarily from the black mold. HISTORICAL. In considering the economic importance of the black and the yellow. molds of ear corn and broom corn in the Southern States, it is surprising to see how little mention is made in the literature about these diseases. Some entomologists early recognized the economic impor- tance of these molds. ‘ Garman and Jewett (12) in 1914, in working with the corn-ear worm and in mentioning the extent of injury from this pest, state that seasons when corn mold is. prevalent are merely seasons in which the insects have been especially common. Similarly, Bishop (3), in 1917, while working on the boll worm, or co-rn-ear worm, stated that in some regions, practically every ear of sweet corn was ‘damaged, and that throughout the entire country 70 to 90 per cent. *Monthly Crop Reporter, ~U. S. Department of Agriculture, 5:121-140, Dec. 1919. 4c TEXAS AGRICULTURAL EXPERIMENT STATION. of the ears of field corn were attacked. Following this injury, molds frequently gain access to the ears and damage them still further. This is especially true during Wet seasons. Although the specific nature of the molds is not stated, it is reasonable to infer that Bishop was deal- ing with the black and the yellow molds, which are widespread in most of the Southern States. The great importance is -the association of the ear-worm with the ear molds, a condition as is shown on page '7 that practically prevails in Texas. As will be seen later, the cause of the black and the yellow molds of ear corn and of broom corn is due to two fungi belonging to the genus Aspergillus, namely: A. niger and A. flaws. Not only is A. niger, as determined by us, involved in the black mold of ear corn and broom corn, , but as stated by Wayne (37 and 38), this fungus is responsible for serious damage to stored onions in Ohio. The same condition also prevails in Texas, especially in the Rio Grande Valley, where the onion crop is seriously damaged by A. niger. The black mold damagesthe crop more seriously when the onions are. dug during wet weather, also making v them more unfit for shipping. The symptoms of black mold of onions will be taken up on p. 18. Besides the onion, McMurran (24) reports an internal rot of. pomegranates which he attributes to a fungus, Sterigma-tocystis castanea Patterson. As will be shown later, no dis- tinction is made in this bulletin between Sterigmatocystis and Asper- gillus as they are considered identical. Hodgson (18, 19, and 20) also records a pomegranate rot which he attributes to Sterigmatocystis cas- tainea and a smut o-f figs also believed to be induced by the same fungus. sStevenson (33), while studying the cause of the rotting of citrus fruit in Porto Bico, found that among the many decay-producing organisms, Aspergillus niger was an important factor. Brooks and his col- leagues (5) found that among the many rot-producing fungi, A. n/iger, was able seriously to injure ripe apples both on the market and in storage. Beille (2) found that Aspergillus niger and A. flaivus were both involved in a stinking rot of coffee grains. Stoykowitch and Brocqrousseu (34) found that Aspergillus and Penicillum were respon- sible for the deterioration of dried prunes by reducing the sugar and acid content. The Kopeloffs (21 and 22) found that among the many fungi, Aspergillus niger was important in the deterioration of cane’ sugar. It should not be supposed that all species of Aspergillus are harmful. Wehmer (40) records that Aspergillus oryzae is very im- portant in the brewing industry of the Japanese saki. Likewise, Han- zawa (15) states that Aspergillus oryzae is the chief fermentative agent in the manufacture of the Tamari-Kojii, a Japanese sauce made of soy beans. PRESENT WORK. The importance of the black a11d the yellow molds of ear corn and of broom corn in Texas has already been indicated on page 3. In the present work, an attempt has been made to determine the following: (1) The distribution of both the black and the jvelloxv molds in Texas. (2) The exact relationship of Aspergillus niger and A. flavus to the molds of ear corn and broom corn. (3) The range of hosts of these two species of fungi. (4) The presence, if any, of physiological species. (5) The pathological effect of black mold on the germination of grains from affected ear corn. A STUDY or BLACK AND YELLOW MoLns OF EAR Conn. 5 (6) The morphology and physiology of A. niger and A. flat-us. (7') Methods of control. The Writer wishes to express his indebtedness t0 Dr. Charles Thom for many courtesies in verifying and. identifying species of Aspergillus. Acknowledgment is aim due Messrs. A. B. Conner and A. H. Leidigh of the Division of Agronomy, to Mr. H. B. Parks, of the Division of Entomology, and to Mr. A. S. Ware, secretary, for helpful criticism in reading the manuscript. DISTRIBUTION OF EAR MOLDS. As far as the ear molds of corn are concerned, it is necessary to dis- tinguish between the black and the yellow mold. The term black mold or yellow mold is here used in preference to smut, as the disease is now erroneously known. The black mold, especially, must be distinguished. from the true smuts of corn and broom corn in order to gain a clear conception-of the difference in methods of treating these diseases. The black mold of ear corn may be generally found wherever corn is grown in Texas. As will be shown on page 24¢, this mold is moreiprevalent during dry seasons, although it is not uncommon during wet weather. The yellow mold, on the other hand, seems more restricted in its dis- tribution and is especially prevalent during wet seasons. It should be emphasized in this connection that where yellow mold is common, black mold of ear corn is practically unimportant. _ As to the broom corn, both the black and the yellow molds usually occur together in the fields, being more prevalent on some varieties than on others. The great- est amount of damage to broom corn, however, is met with when the crop is harvested during wet Weather and while green, when shipped before being thoroughly cured, or when loaded in cars which lack the proper amount of ventilation. SYFIPTOMS. As the names indicate, the black and the yellow molds of ear corn attack only the ear and no other part of the corn plant. In the field there are practically no symptoms to indicate the presence of black moldy ears, inasmuch as the disease is confined to the interior of the ear itself and not to the exterior of the husks. It is only during harvesting and husking that the disease becomes apparent. The same is also true for the yellow mold, which is confined to the interior of the tip of the ear only (Fig. 3, a and b), in which case the infected grains are undersized, shriveled, and covered by a yellow growth which, if this growth is closely examined, it is found to be made up of numerous yellow-to-greenish heads, which are really the spore sacs of the fungus Aspiergillus flavus. Yellow mold in the field seldom invades more than one-third or less of the tip of the ear. In this case it is nearly always found on varieties with erect ears, which catch and hold water from rain or dew. With the black mold, however, the disease is seldom confined to the tip, but follows any opening made by the ear worm (Figure 1, a, b, f, g, h, i, and j). In tearing open the husk of an infected ear one finds its entire surface is covered with a black powder, giving it a dark, sooty appearance (Figure f2, a, c, d, and e). The grains of such an ear are black, undersized, and in most cases shriveled and blackened (Figure 1, _i). Invariably, and on close examination, it is found that infection TEXAS AGRICULTURAL EXPERIMENT STATION. i FIGURE I. a.. and b. Black mold starting at tip of ear and following ear worm injury. b. Same as a. exrept that the grains on the tip of the ear were removed to show that the black mold had penetrated the cob. c. Ear corn injured by the ear worm showing also the tunne's made by it. d. Two (torn-ear worms. e. Eggs of corn-ear worm caterpillar. (c. After Quaintance and Bruce. d. and e. After Garman and Jewett.) g. and h. Black mold o? ear corn starting in the middle and following the opening made by ear worm. i. and j. Two young ears of corn injured by ear worm and then destroyed by black mold. A STUDY OF BLACK AND YELLOW MoLns or EAR Conn. 7 of the black mold starts at the point Where insects, especially the corn ear Wo-rm (Figure 1, d and e), have penetrated through the husk into the ear. The ear Worm in feeding (Figure 1, c) produces considerable excrement, Which is generally moist, thus offering an ideal medium for the entrance of Aspergillus niger. In early infections, the blackest part of the ear may be localized at or near the place of the Worm injury. If the affected ear is young, tender, and in its milky stage, the fungus A. niger‘ Will be seen to spread rapidly from the point of entrance of the ear Worm to the entire inner surface. When, hoWever, the ear is partly ripe, infection Will remain localized Within the feeding area only of the ear Worm. Infection‘ seldom takes place on thoro-ughly ripened ear corn, because at this stage it is practically free from ear Worms, which prefer more tender plant food. On the exterior outer husk cover there is seldom any blackening to indicate interior infection. The husks next to the interior of the ear are, in severe cases, covered by a black dust of Aspergillus spores, Which is c-onfined to the layers nearest to the grains. As already stated above, the black mold of ear corn follows injuries made by the corn-ear Worm. It should be added that in Texas other insects, as Well as rodents and birds, are all responsible for open- ing the Way to black mold infection. The corn Weevil, Which is also troublesome to ear corn, does not seem to play any role in favoring infection, because the Weevils attack only mature ears, especially under poor storage conditions. The symptoms on broom corn are de- cidedly different from those on the earicorn. The heads of broom corn When affected. by the yfelloW and the black molds have a dirty black- and-yellow appearance, the grains becoming covered With fungus threads of both Aspiergilius niger and A. jiavus, and frequentlyi also by numer- ous other organisms, especially Fusarium, Which give the broom corn heads a decidedly moldy appearance (Figure 3, c and d) and a charac- teristic stale odor. Frequently, as a result of the molds, the broom corn becomes shriveled and lose their germinating poWer very early. As With molds of ear corn, the molds of broom corn are favored by the attack of insects or by improper curing. Furthermore, as already mentioned, some varieties are more susceptible than others. CAUSE OF THE BLACK AND THE YELLOW MOLDS. The fact that Aspergillus niger and A. flavus are always associated With black and yfelloxv molds of ear corn and broom corn in Texas Would indicate that these organisms are the cause of the trouble. From a scientific consideration more proof is necessary. It is extremely easy to isolate both Alspergillus niger and A. fiarvus, since both. of these fungi fruit abundantly on their hosts. All that is necessary is to take a bit of tissue from the affected host and drop it in sterilized Water. Dilu- tion plates from this Water, Which contains the spores of these tWo organisms, Will yield pure cultures of A. niger, A. flarus, or both. From the plate cultures, the tWo organisms may readily be transferred pure to slanted tubes, and then used for inoculation-purposes. In order definitely to establish the cause of the black and the _velloW molds of ear corn, artificial inoculations Were begun on ears both in the field on the growing plants, and on cut ear corn brought into the lab- oratory. Inoculati-ons Were made on ears in every stage of develop- ment; that is, those Which Were barely formed to those Which Were 8 TEXAS AGRICULTURAL EXPERIMENT STATION. FIGURE 2. a. and b. Two young ears of corn attacked early by the ear worm and later destroyed by black mold. The grains failed to fill out properly. c. Ear corn totally destroyed by black mold. d. Shucks, of ear corn in which the cob has been removed to show the black- ening of the husks by the black mold. e. Ear corn destroyed by black mold same as d, from which it has been removed. f. Young ear corn cut longitudinally to show black mold Working into the cob. A STUDY OF BLACK AND YELLOW MoLDs OF EAR CORN. 9 . FIGURE 3. and b. Ear corn affected l_)y yellow mold, which nearly always works at the tip of the ear. e. Cowpea ; affected by Asperglllus mger at the base of the stem. c. Two heads of broom corn affected by black yellow mold. d. Healthy head. .10 TEXAS AGRICULTURAL EXPERIMENT STATION. fully matured. The methods of inoculation and the results obtained. are indicated in Tables 1 to 5. Fromjthese tables, it is clearly evident that infection can take place 0n ear corn only when it is in its milky stage and not when it is fully matured and hardened. Furthermore, infection is only possible when spores of Aspergillus niger and A. flavus -. Occasio-n- to grow at the place of infection j but here, however, the fungus does are introduced through a puncture in the soft tender ear. ally Aspergillus spores may start where there is no needle puncture, fl<fl 13.1mm.» Amuhi 4.4m. <4 v: i‘? x < not spread internallyY and only develops superficially at the place where) the spores are deposited. No inoculations were tried on any of the Nevertheless, initely show that ripe and mature corn is not subject to the ear mold and that an injury is necessary for infection. This is what actually takes place in the field, and, as previously stated, the injury is brought about through the work of the ear-xvorm or other insects when attack- ing the ear in its milky stage. This is especially emphasized because of numerous statements made to the writer by various growers who believe that both the yellow and the black molds of ear corn are brought about. when the corn is left too long in the field after harvesting. broom corn. the results obtained on ear corn do -i 11 A STUDY OF BLACK AND YELLOW MOLDS OF EAR CORN. 00x05 .30; 0:::0::: .0m0:0U 32> 0:::0:n: 00 0:0: ::00 :: 0:0 00:50.0 :0:00::00:1. .00: :0:0: :0::0 000:0>E :: 000E005 0:00 00005005.: 0.050.000 00:00:00: 0:0 003:: :m:o::0 0.50005: hm .:0:000.0E 07: . . . 25:00 500:: 50:: :03: A: .520: .00 .w:< m: 52000.5: 07: . . . . . ..::00 :00 50:: 0.200% .:\ Fla: 6N .000 0:50.00 ME:::.E 0:0 0:5: :m:0::0 0::00::: hm m .000: 0.00:0 o7: .:0:000.:E 0Z . . . . . . . . . . . . . . . . . . . . 500:0 ._.w:m: dm .03: $520 05:25 0:0 0000:: :w:0::0 0505:: hm m .:0:000.:E 07: . . . . . . . . ..:0::0 50:: :05: .:\ .530: .00. .03: *m::0:w 05:50:: 0:0 0:5: :m:0::0 0:50:00: hm o: .:0:000.::: 07: . . . 10:00 500:: 50:: .002: .0. +w:m: dm 0:4 05:00»: M555: 0:0 0:5: 0009:: 0::00::: hm m .:0:0000:: 07: . . . . . . .::00 :00 50:: :05: .:\ 30:00: dm .030 0.0505 M555: 0:0 0:5: :m:0::0 0505:: hm m :0:0:>: 0:0 :00.0< :0:00::005 .:0 3500M: m:::u:0:m< :0 00::0m :0:00_:005 :0:00::00:: :0 00:00:>: 00005005 00 000D 50m :0 .07: .00:.0::: h::.: ::00 :00 :0 :0:00_:00:: 0:0:n:|.m 030B .:0:000m 000:0“: 00 :00:0w 050: w..:0:0:0 0:0 :: 050:: :50 :0 0000::00:: 50ml. .mw::0::0:.::m 00.05 0000:: 00 0:00 m0? m::.:. 0:0: :0:::: h: 00:00? 0:0 m0: :0:0: :0::0 000:0>E E 00m0:0:0 0:00 000050050. . 0m: 005:0 07: . . h . .h:0_00: :4 . . . . . . . . . . . 100:0 .53: mm 0:5. .2580 ME::.::: 0:0 0:5: : :0::0 0::00::: hm h 000.005: . 3:0: :00:.:050.: 000005: 5::005 0:00 v . . . .. . ::00 50:: 0:50? .:\ .520: .m 0:5. 0.05000 055.8: 0:0 0:5: 0009:: 0::00::: hm w .000.00:E h::w:0:0:0 0:00 o: :< . . . . .:.:0.0.500:: 50:: :05: .:\ 30:0: .m 0:5. 1.50:0 055:5 0:0 00:00:: :m:0::0 0505:: hm o: . 00000.5: h::m:0:0:£00m0.:0000::w:: :4 5:00: 50:: :05: :\ ._.w:m: m 0:5. .1550 ME:::.E 0:0 50:: 0000:: 0::00::: hm w: h_0:m:: h_:0 :00E05.0: 00000.5: h_:m:0:0:0 5.00 m ....m~..00:0:m050: 50:: :03: :0. 33m: mm 0:5. .3520 05.5.3: 0:0 0:5: :w:0::0 0::00::: hm m: 00000.5: h_:w:0:0:0 0:00 N: :< . . . . 0:0: :00000 50:: :03: :\ K020: .m 0:5. 00505 05.5.5: 0:0 002:: :m:0::0 0::00::: hm m: 000005: h::w:0:0:0 0:00 N. :4 0:00 :50 E0:\ :03: .:\ ._.w:m: m 0:5. *mE0:w 05.5.5: 0:0 0000:: :m:0::0 0::00::: hm N. 0h0Q om .0030 :0:00::005 :0 0:51.00: 03:50:04 :0 00:.:0w :0:00_:005 :0:00::005 .00 00:00:>: 00005005 00 000m: 0.00m: :0 .07: 000:0 h:::5 5:00 :00 :0 :0:00::00:: 000E]: 050k. 12 TEXAS AGRICULTURAL EXPERIMENT STATION. .. . .18.. 00000.00. 00:80.00 0100...... l0... 1.... 0. M...» .:o.00..0:0o:0 .00 0:00: $5000.50 00: 00 000.2000 00003 00.0000 .0 0:000 m. .3500: 50:3 .:0000_:005 00 050: 00 0.0000005 003 35> . . . . ....:000 000 E000 00E: .00 m3: .00 00:0 0:0::3 0000:: 000:: 050.5 :0 0000000 0000mm N0 05000.. 0 00: .:000000 00 00:00:50 .:00000...00:0 .00 0.50: 00 x003 3000000000 :00000.0:~ . . . . . 1:000 000 E000 000.0: .00 M002 i»; 0:5. 0:0::3 0000:: 000:: 0500M :0 002.0000 0002.0 m0 . .:000000.: .0Z ....:..00 : 000: E9: 0:00: .00 00000 .N0 0:3. 0500.0 055:5 0:0 0000:: 0000...: 0505:: mm m .0000 m :0 :0:000.05 x003 35> . . . . . . :00... 000 E9: 00E: .00 M22 .N0 0:5. 05000 05.550 0:0 0000:: :m:9.:0 00:00:.W: 00m Z .500 .0000 0 :0 :00000.E0 00003 >00> . . . . . . 3:000 000 500.0 00E: .00 M002 .w 00:0. c0 0.5.0.: 0:0::3 0000:: :0:9.:0 00.000.00.00 00m >0 .0000 c0 :0 :0 :00000.0:: 00003 3.0.? . . . . . . .:000 000 E000 0050K A.‘ M002 .00 0:3. .0520 0.50.0.5: 0:0 0000:: 00:00.00 00:00:00: Em o0 .:00000:00E .00 0000: 00 0000 n0 :0 :00000.0:0 :00? . . .000:00m0Eo: E9: 00E: .00 m3: .00 0:3. .3500». 055...: 0:0 50:: :m:0..:0 00:00:50 hm 0N .:0000_:00:: .00 0000: 00 0000 c0 :0.:.0 :o0000.0:0 :00? . . . . . . . . 00:00: E000 00E: .00 mZZ .w 0050. *05000 055:: 0:0 0000:: 00:00.00 00:00:50 Em m0 .:0000_:0o5 00 0000: 00 0000 0m :0 :00000.05 :00?» . . . .. 000 E000: E9: 00E: .00 M050 .w 0:3. 0.05000 0505.0: 0:0 0:5: 00.50.: 00:005.: 0mm mm ._..:00000:005 00 0000: 00 0000 m0 :0 :0 :00000.0:: 0000.5 . . . . . . .:000 000 E9... 00E: .00 M002 .w 0.50. 0.0505 05.50:: 0:0 500:: 00:8... 00:00:50 am m0 50D 3:03P 000.04 :0000_:00:H 00 0500M 000D 0.0005003» .00 000:0m 000005005 :00000:00:~ 00 00:000.: 000.00.000.00 00 000G 000M 00 dZ .050-_.E00 .:000 000 00:0000D|.0 050E .00E00Z 300.? 00.53% E9: :50 00m? 0:00 000:0 00.0 00:E0:0 006E 5 000v? .00:E0:0 006E 5 000.00.... 50:00.3 0:0 500m 00 >001: 0.00.0003 00000.05 300E m0 . . . . . . .000 :000 E9: 00E: .0. M002 .0 0:5. 0:: 0:00: 5 00:00:00 .~...0.6w..0 00000050 0000mm mm *.500 00 5.5 0:00:00? 000000.00: 200E m0 . . . . . . .000 0.000 E9: 00E: J0 one .0. 0050. 0:: 0000:: 0: 00:00:50 00.09:: 05.00%.“ 0005mm hm . . .000:00005 00003 :0..3 0:: 5.5 00000.00: 3000:0005 0000 0?. . . . . . .. .000 :000 500.0 00E: .00 wfifl .0 0:3. 50:03 0000:: 000:: 05.2w 0000000000 0000:m m0 . 00:00:: 00 000000 5500005 0:00:00 M53050 m . . . . . . .000 :000 500.0 CE: .00 M0200 .0 0.50. 0:0:003 0:0 0000:: 0005.... 050E :0 000000.50 02200 W0 .0000 00.500::: 00 000000000 :50.0005 000000.: 0000 o0 00.3000 00: 0000 E9: 0:005 .0. M22 .m 05.0. .1206: 0505.: 0:0 0000:: :m:00:0 00:00.5: 00m o0 .0000 00505:: o0 00500000 003000.00: 0000005 0000 m0 0000: c000 E000: E9: 0:00:50: m5: .m 0:3. 0.05000. 05.5.05. 0:0 0000:: :m:00:0 .0.500::: hm m0 .0000 00.50005: 0000500000 :00000.05 00000.05 0000 0m . . . . . . . . . .0000 E9: 0:00? .00 x000 .0. 0.5:. 0.0.0.000 050:5: 0:0 $0.5: 0000950 00:00:00 Em 0N 0000005 >0:m:000:0. 0000 o0 . . . . . . . 000300 E000 00E: .0. M050 {m 0.50 *0500m 0505.5 0:0 0000:: :m:00:0 00:00:50 hm m0 00000.05 0000:0005 0000 on . . .000:00m0E0: E000 EE: .00 M002 .m 0:00. 0.05.000 055.05 0:0 3.00:: 00.60.: 00:00.5: 00m mm 0000005 >0:m:o00:0 0000 0N . . . . . . . . .0::00: E9: 0E: .00 M050 .m 00:0. 0.050000 05.505 0:0 00.00:: :0.60:0 00:00:30 0mm: mm .00000.0:: >_:m.:000:0 0000 m0 . . . 10:0: 0.00000 E9... 00E: Aw m0m0 .m 0:5. *0....000 @5505 0:0 0000:: :m..00:0 00:00:00: hm .2 0000005 3000500900 0000 0m 0000: F00 E0. 0: E9: 00E: .00 M050 1m 0:5. 0.05000 00000.5 0:0 0000:: 00.62: 00:00:50 >m hm .000000..: Z:m:00o:0 0000 m0 . . . .0500 :00:00 500.0 00E: .00 M023 .m 0:3. 0.050% 0550.5 0:0 0000:: 00.60.: 00:00:20 00m mm 00000.05 0.0.0.602: 0000. i. . . . . . . . . . 500:0 E9: 00E: .000 002$ .m 0:3. 0.0505 05.50.: 0:0 0000:: :m:00:0 00:00:50 >m~ 00 0000005 00.00.600.00 0000 ow . . . . . . .:000 000 E9: 00E: .00 M02: .m 0.5a 0.05000 M5505 0:0 0000:: :m:00:0 00:00:50 hm mm 200D 3:03P 0000< :0000_:00:~ .00 00:00.00 000D 5:030:04 .00 095cm 0000050000 :0000_:00:0 00 00:00.02 00005005 .00 000D 000M 00 .02 020M000 5:05 .9000 00H 00:0000Q||.m 050m. 13 A STUDY OF BLACK AND YELLOW MOLDS OF EAR CoRN. .0500 00.23 000. 0090000 02000 0m 000v? . - - . . -< -¢~.->-.-.-|..- . . . ¢ - . . - ¢ $.00 000x v00 :0 E 000/0500 00500000 0Z . . . . . . .0000 .000 E000 000.00 Ax n22 0m 400w 0x000 .0000 001000 0003000 .000 030000 00005 m0 .9500 00300.05 0Z . . . . . . .0000 000 000.: 000.00 .< M22 .NN 000m m0 00000.5 000 000000.000 000000 0300000000 0000i Z .2500 $00000 00 B0000 00 00300.05 1000000000 .00 0003M. . . . . . . .0000 000 06¢ 000.00 .< M32 .om 000m m0 00000.5 000 00080000 202m 030022 $10G m“ ‘M00300 00 006000000 M5002 $030M 00 30000 00 00500000 300000000 .00 0022B . . . . . . .0000 000 000.5 000.5 Ax M32 6N 400m |000 00003 0:030 E 0000mm .000 000/0800 0x003 o0 . 000000.000 00 000 00300000 0Z . . . . . . . . . .0200 000$ 000.00 Ax wflfi 5m 000m 0020 000 0x000 0003000 000000 005000 302005 a 0058.00.00 00 000 .0033?“ 0Z . . . . . . . .000 0.000 000C 000.00 .0‘ wfifi .3 400m 0020 000 0x000 0003002 000000 000000 0:05.010 mm 02000000 0Z . . . . . . .000 0.30 000$ 000.00 4x wfimfi .m~ 000w 100000 0000.00 000 0x000 000005 0.0000000 am 0N .00B00.~0@ oz . . . . . . .000 0000 000G 000.20 AN M32 .m 000m *m0@00m 00000.00 v00 .0060: 0003.0 00000000 %m_ 0% .00$0_000E .00 0050 00 0030.5 03:96.54 00 0000B . . . . .. . ..J00000 000C 000.00 JN wfimfi in. 000m “E5000 00000.00“ 000 0x000 0000.05 00000000 hm 0N .00S0_0000m 00 000E 00 0030.5 005000030 .00 000C. . . . . . . .000 0.000 000$ 000.0: A‘. M32 .m 000m 000000.00 M00215 100 0x000 0w00b$ 00000000 >0 m: .0000? ZEN .0084 005200000 00 800000» 000D 005000004 H0 030cm 003200000 00320005 .00 00502 00220005 . .00 000G 0.00M .00 .0Z 00000? >200 0000 000 w0n030fll.m 050E 14 TEXAS AGRICULTURAL EXPERIMENT STATION. The younger the ear during infection, the darker it is when harvested because at this early stage the fungus has had an ideal medium on which to grow. Furthermore, the moisture under the husk of the young ear seems t0 favor the fruiting of A. niger and A. flcwus, both of which readily shed their spores, giving the characteristic black or yellow dusty appearance to the affected ears. When infection takes place at an early stage of the development of the ear, Aspergillus mlger, especially, may also gain access to the interior of the cob and give it a black charred appearance. The black color of the cob is brought about primarily by the color of the spores of the fungus, the latter of which sporulates profusely in the interior of the tissue just as readily as it does. on the surface of the grains under the husks. The mycelium of both species of Aspergillus is white to yellowish. Sporulation seldom takes place on the outer surface of the husk, for which reason it is not always easy to tell the amount of ear-mold infection until after harvesting and shucking. 1s BLACK MOLD A STORAGE DISEASE? To further determine whether or not both the yellow and the black molds may be spread to healthy mature corn in the crib, the following ex- periment was carried out during the winters of 1918 and 1919: In each case, 10 bushels "of healthy ear corn in the husk were secured from Prairie View, Texas. This corn grew on good land and developed into normal, well-formed ears. The corn was also well matured, as it was allowed to stay in the field until late in the fall and was gathered when there was no rain. These ears, having been husked and stored in a crib, were arranged into layers of (a) healthy, and (b) infected layers. The ears in each layer were properly counted and allowed to remain undisturbed during the entire winter in a crib well protected from rain. Early in the spring, the corn was taken out and carefully examined. It was found that the same number of healthy as well as black moldy ears were taken out as were originally placed in the crib. This proved conclusively that the black mold of ear corn does not spread in the crib even though diseased ears are intermixed with healthy ones, provided the corn is kept dry. Similarly, three bushels of healthy mature corn secured from Prairie View were intermingled with dis- eased ears affected withthe black mold and stored away in a crib. The corn was sprinkled with water once every two weeks, so as to keep it moist, and the ears were left undisturbed during the entire winter. Early-in the spring, they were taken out and examined. It was found that numerous species of Fusaria and Aspergillus niger were growing on the exterior husks giving them a somewhat black, dusty appearance. Aspergillus, however, did not penetrate the interior as to injure the ears, which were fairly ruined by Fusarium. This indicated that moisture does not seriously encourage black mold on mature corn as it does Fusaria. This also agrees with the results of the artificial inocu- lations as reported in Table 5, and with. field observations. In the field, mature corn when exposed to wet-weather conditions mav be ruined by Fusaria, but not by Aspergillus. It is not intended here to» give the impression that there is no harm in keeping stored corn under moist conditions. Such a practice is never carried out. The point brought out mainly is that the black mold of corn does not spread in the corn crib under dry storage conditions. This further strengthens the proof-that black mold is a disease which follows insect injury in the field, and A STUDY or BLACK AND YELLOW MOLDS or EAR CORN. 15 _infection only takes place When the ears are in a milky stage and not after they are well matured. CARRIERS OF BLACK MOLD O11‘ EAR CORN T0 establish the relationship of the corn-ear worm (Ohloridea obso- Zeta) to the black mold of ear corn, the following experiments were tried out: ~A large number of corn-ear worms were collected from acorn field. These worms were gathered from young ta.ssels and young ears, and brought to the laboratory in sterilized test tubes containing ster- ilized water. These were then placed on an. electric revolving machine and shaken for 20 minutes. The water from these vials was then plated out in ordinary petri plates containing agar agar. Of the many organisms isolated Were AspergiZZ/us nigeo" and A. flaivus, Penicillium, Fusarium, and a large number of bacteria. The Aspergillus isolated seemed to be identical with A. niger and A. flaivus originally obtained ‘from diseased ear corn. This proves that the ear worm does carry on the exterior of its body spores of Aspergillus as Well as of other fungi. A large number of ear worms were also collected from the tomato and cotton bolls and treated in the same way as those collected from ear corn. Aspergillus and numerous other organisms were isolated from the water from the worms thus collected and rein-oculated in young ear corn, cotton bolls, and tomato fruit (see Table 6). , Aspergillus flatnts and more especially A. nriger are frequently found on cotton bolls which in the field were previ-ously attacked by the cotton bo-ll worm. The latter often caiises considerable damage to cotton b-olls, and invariably boll rot (Pseuidomonas maloacearum) follows the injury of the boll worm thus causing the boll to become softened and to decay. At this stage, it is very common to find Aspiergillus niger invading the diseased bolls, which turn black, on account of the spores of this fungus, which fruits abundantly on the outer surface as well as in the interior of the boll tissue and lint. Frequently, also, Aspiergillus niger invades the cotton boll immediately after it has been injured by the boll Worm, in» which case the affected bollbecomes semi-dry rotted and later shrivels and blackens. With tomatoes, when the fruit isjnjured by boll worm, Aspergillus nigelr, although frequently found at the place of injury, does not seem to cause a decay as long as the tomatoes are green and in a. growing condition. As shown in Table 6, however, tomato fruit, when detached from the vines, will rot if inoculated in . the laboratory with spores of Aspergillzts niger or A. flatvus. In transit, when the tomatoes are packed poorly or carelessly, or when fruit infested with the ear Worm is shipped they Will often black-rot as a. result of the secondary invasion of Aspergillus ntger. ‘ Hence it is seen, from an economic point of view, that A. niger and A. flaws are important not only as causing the black and the yellow molds of ear corn and broom corn, but also as being a semi-parasite on cotton bolls, tomato fruit and other plants. 16 TEXAS AGRICULTURAL EXPERIMENT STATION. .202 0025.02 2053 525m .202 0.32502 2053 625m .202 ©350m 20253 625m .202 ©2500 20253 525m .52 ©0250» 2553 025m .2202 .25 2 .2202 .202 2.5m .202 2.5m .302» 222222202 .202 2.8m .3022 222255.202 2.5m .25 2 .2202 . .2202 .2202 .2202 .252 .2202 .2202 .2202 .252 .252 .252 .2202 .2202 .252 .52 2.5m $50.2 .52 2.5m .2502 .202 2.20m $502 .202 25m .0522 .202 25w .0502 .202 2.20m .202 25m .202 25m 222222 2522 .202 2.5m 222222 22.222 .202 2.5m 22222.2 2522 .202 2.5m . 222222 22522 .52 2.5m 2222.2 22522 .202 2.5m . . . . . . . . . . . 321m JmOZHOMNZ: - 2 - - n ~ ¢ . - . - - ~ - - . - - ¢ . . - . . - - - - - . - ¢ -. . . . . - - | ¢ - - - . . . . . . . . . . . . . . . . . ....... 22022002222 02 . . . . . . . . . . . . . . . . .........2202200222202 .... . . . . . . . . . . . . . . . . . . . ..22022002222 02 . . . . . . . . . ...............©u20o22222$w2 . . . . . . . . . . . . . . . . . . .......QO$UQZI gom. . . . . . . . . . ...............C02wOQ.Z: . . . . . . . . . . . . . . . . . QAZQZGQZ Rs/ZQNWQZ . . . . . . . . . . . . . . . . QWJZNQZ ZN Jgrsflmwmvz . . . . . . . . . . . . . . . . . ZZN QQ>ZHNuUZ . . . . . . . . . . . . . . . . . ZN .U>ZHNNQZ . . . . . . . . . . . . . . . . . QmZZNOZ ZN JE/ZHGWQZ . . . . . . . . . . . . . . . . . .2WZZNQZ Z6 2Q>sflwvz . . . . . . . . . . . . . . . . . QWSZNQQ ZN .®>sflw0z . . . . . . . . . . . . . . . . . QWZZGUZ ZN XE/sflwwz . . . . . . . . . . . . . . . . . QWSZNQZ ZN RYPSNWQZ . . . . . . . . . . . . . . . . . .>Z..ZNUS ZZN 2U>ZHNmUZ . . . . . . . . . . . . . . . . . QflZwZNQZ ZN .G>ENMQZ . . . . . . . . . . . . . . . . . .>gaZmwQ§ ZN 2U>ZQNwUZ . . . . . . . . . . . . . . . . . .2AHZ.ZWOS Zfl JX/SNWUZ . . . . . . . . . . . . . . . . . .>Q.~ZNQZ. Z5 2U>@.~N%Qz . . . $2225.22 25 4.225502 . . . . . . . . . . $222252 0552 2202202222 2X25 . . . . . . . . . . 52222202 222.252 22022002222 $2.2. . . . . . . . . . . .mH~Z@POH ZZQNH “QQZQUQZQZ . . . . . . . . . . 5222252 22225.2 .22022002222 2R1. . . . . . . . . . . .miZHPQH ZZQGM JBQZHUUZQHZ . . . . . . . . . . . .®:Z.##QH BOZW JhAvZQBvUZQZ . . . . . . . . . . . .mqZ.wgQk RIQZW JMOZHUQ-ZHMZ . . . . . . . . . . . .w=ZH.wOh QIOZD “QQZPUQZHMZ IIIOUQIQOIIIIII%QQZQ® ..-. . . . . . . ..~.-.->.QQZQQ§ZZN ¢@>wwfi Qz . . . . . $222522 25 5225222 . . . . . . . . . . . . . . . . . Jmfifimofi ZN 62222522072 . . . . . . . . . . . .wG2.:02 302m .GO§0®.~C2 2X0~N . . - . . . . . . . . . .xgZw.wok >>>°Zm .QQZQUQ.ZQZ . . . . . . .®-HZ.WGO.~ ZIOZM JMQZQOQZQZ . . . . . . . . . . . .wflZdaOh BOZQ JMQZQUQZQZ . . . . . . . . . . . -wHZ.~.wOh R/OZM JMQZQUQZHZ . . . . . . . . . . . . . . . .22302m 222222 £202.50 0.... . - . . . . . . . . . . - . . . . . . . . . . . . . . . . . .22302w 32222 £20250 ow . . . . . . . . . . . . . . . 2230.5 2:222 £20250 ow . . . . . . . . . . . . . . . .22302m D2222 620250 ow . . . . . . . . . $2.205 @2553 w £22522 222252225 w . . . . . . . . . 2.225 2503 w 6225222 2552225 w . . . . . . . . . . .105 2503 w £22572 22522022 w . . . . . . . . . . . . QMRIORW $wZ5hw ZDNUUM . . . . . . . . . . . . .=2£I°k@ ».#:Jh% ZWNZZW . . . ' . - . . . - ~ I . . . . . . . . . . . . JHKOMW rZURw SwfiDUU . . . . . . . $2.05 2503 m 325222 22222222220 2. . . . . . . . 2.205 2503 m. m222w72 2022222220220 h . . . . . . . 2.05 2503 m 325222 2022222220220 n . . . . . . . .105 9503 m m2255 202222220220 n . - - - . - . - . - . - 2 - - . - . . . . - - 1 - - . - - » . . . - . - ' v - . . . . . . . . . . . . . IQQZR QHZH~H% EQQEfiKYSU . . . . . . . . . . . . . Jvfli fzn-Pw kUQEDOH-w . . . . . . . . . . . . . IQQZH CwZA-ZQ kUQE-Hnvflwu . . . . . . . . 2.205 $503 o2 22225222 052252 w . . . . . . . . 2.225 2553 o2 22225222 0522202 o . . . . . . . . $2.225 $503 o2 22225222 052252 w . . . . . . . . 2.05 2.20503 o2 @2255 0522202 w . . . . . . . . . . . . . . .2222 .2522 2222.22 05:52 mm . . . .- .-. .. ...............UQZH%ZNZQZHYMZOZQEQH . . . . . . . . . . . . . Z2222 .2522 22222.2 0522202 mm . . . . . . . . . . . . . 102.2 .2522 22.2222 052.2202 mm . . . . - ~ - . - - . . - . . - . - - . . . - - - - . . . - - - . - - . - - . - . -».n--. ¢-.-mcoa . - - » . . . - . . . . - . - . - - . - - - - . . - ¢ - - - . . . - - - - . . - . . . . 2.05 222220222 N2 225222 2522 M53020 . . . . 2.05 22225222 m2 225222 2522 M23026 .... 2.205 2222220222 N2 222220 22522 M53020 ‘.2 . . . - . - ‘a....--.-mqoggwogc®xmwkm . . . - . - . - . . . . - - . . . ~ n - - - » - . - - » . . » . - - - . - ¢ . . . . . . - - . . . . . . . . - . . - . . . . . . . . . . . - . . ~ - - . - . . . . . . . . . . . . . . . 122200 22200.5 22202.2 2.25205 .22 - - - - - . . - - - . .-o-.o§.®® . . . . . . . . . . . . . . . . . .w5ifl0Q 50.2.2 ku§~= .5 . . . . . . . . . . . . . . . . . .. 2.20220 80.: kwgzk . . . . . . . . . . . . . . . . ..~N0 GhOU 602.2 M002: .5 .-~.. . . . . . - . - . - n.-.c°rgo .< . . . . . . . . . . . . . . . . .ufl0 ERGO 80.; WBQUZ. . . . . . . . . . . . . 122.200 22200222 22202.2 22:52.2 2x . . . . . . . . . . . . . .2250 22200222 222022 §5§ .22 - . . » - . . . . . . . - - - - . . . . . . . . ............25225 22202.2 25.222 .2‘. . . . . . . . . . . . . . . - . -H@Q CMHMU E°¢m% HU§-~= -< . . . - . - . . . ~ . ..~....=°Z=° .< . . . . . . . . . . . . . . . . KZWQ i200 E02.“ xwhmi . - . - . . | - - . . . . . . . . . . . . . . . . . . . .2250 22200222 22202.2 2:5? .52 . . . . . . . . . . . . . .2250 22200222 22202.2 2552.2 .22 . - . . . . - - - - . . . . . . . . - . . - . - - . . . \ ' - . - - ¢< . . . . . . . . . . . . . . . - -MQQ ckcnv 1w. . - - . . | . . - . . - . . . . . . . . . . . . . . . 122200 2220022 222022 w==0§ .22 . . . . . . . . . . . . . .2250 22200222 22202.2 0:20? .2‘. . - ~ ~ - . . . . . . - . . - . . . . . . . . . . . . . .... .. 220225 2252.2 222.222 .2‘. . . . . . . . . . . . . . . - . ¢ -< . . . . . . . . . . . . . ................mx025mm - - . . . . . - . . . . . . . . ‘i. . . . . . . . - . . . - . . . . - . . . . . . . . . . . . . . . . . . . .§UNQQ EOM% v2=§~w§ .<. ...............ZZQQc°€€°nvEoH%M-=§Q§.< . . . . . . . . . . . . . . . . . JSGGUQ E02.“ wBbU~\. JN - . - - . . . . . . . . . . . -< . . . . . . . . . . . . . .2250 22200222 2220.22 2.2205 2.2 . - . . . . . < . . - - - . . . n< . . . . . . . ......................32025mm -|... . . - - - -.-.n..uchcmwrfifi@go-Zkmz§uq¢.i . . ¢ . . - - - ' . . - - . - - - - . u.‘ -.. . - . . - . ..-...-..».-.--@@=-fi°mvEo-m.%.NN§k=-< | - - - . . - ¢ . - ~ . - . ~ . - ¢ . -< ----.- ¢ - - - ..-¢-¢:CmmWQEo-fi€-%%u-~=-< . . . . . . . . . . . . COQQOU EOMZ RNQZH .€\ - . - - . - - ¢ - - - - - - - . - O u,‘ 00022220522 m2220222222>m GOSNZUOOGM *0 255m 220522200222 QQOE 22222520 .5 002220m ._..G.2OU .260 Gflflw 2225 @2522 m0 GOZQGZH-OOGM MFZZWQOQM<|HQ QZQNP 17 A STUDY OF BLACK AND YELLOW MOLDS OF EAR CORN. 55055050 .5205 5 550M... £5050 on 00550 05005 5055050050 5055 “x52 .05 >555. 50050550055... .050 75 .050 75 .500 55om|550w .50.. 55om|550w .505 550£550m 05075 05025 500500555 .50.- 505 52052 .0502» UQQOQE: J05 @553 .5502 05025 00500.55 .500 50.505 52052 050055 500500555 .500 5505 52052 05025 500500555 .500 5505 52035 05025 500500555 .505 50005 52052 .0502» 500500555 .505 5.505 52052 5555 50 005000 50550 50 50.5 5.500|550m 5555 .50 005000 00550 .50 50.. 5500550w 5555 50 005000 00550 .50 500 050m|550m 5555 50 005000 000.50 .50 500 5.500-550w .5555 .50 005000 50550 .50 50.. 5500|550w .5555 .50 005000 50550 .50 500 550m550m .050 Z 05075 .................Q°@HU@%=@ C: .U>@H—N%Uz .................-Q@HUU.@=@ C; .U>@.~Nwnwz . . . . . . . . . . . . . . Qwok QIQ@W \GO@QUQ.@~H@ . - . . . . . . . . . .MQ@Q#OH $01G =H~Q@#UU%§@ . - . . . . . . . . . .@fil.wwok 3Q@m ~M~Q@.~.Unw%:.@ . . . . . . . . . . . . . .5558; 5 0250002 $00 55 $00 $00 $00 $5.0 565825 $00 505500.555 .505500555 00M? 505500.55 .505500.55 . . . . . . . . . . . .wfiia.wnvh 3O.—fl Jmnvfiwnvptum . . . . . . . . . . . .MG$wOh 305m .CO$QO.~G@ . . . . . . . . . . . .%H:H#Oh anlm -~O@HUQ%H: . . . . . . . . . . ~ .MQ@#QQM anvfim .=Q@HUU%~H@ . . . . . . . . . . - .%H~5QHQH aoym -=°@PQU%=@ - ~ - - v ~ . - - - . '."-..-.-w=.@€§o-M3°>m . . . . 5530.. 5555005 B050 . . . . $55500 3050 555505 . . . . @5300 B050 5555005 . . . 55550.5 3050 5555005 . . . . . . . .005 305m 5555005 505500.555 . . . . . . . .505 305m 555505 505500.55 505M555 . . . . . . . . . . . . . . . . icofitvnyiuw Oflflmz/fiwflumvz ~ - - - - - - - - - - - - n . . . . . . . . . . . . . . . x WJQQaWmQCWAQNQQCM - - . . . . . . . - - - . - 1 . - . - . . . . . - . - < ~ - . - - - . -.-.-----¢--mwog.@mwgw@xmwrgofi 505w 550555035 00> £0050505 52.55 0.50 55 mm 500.. 550555035 50> 50050505 52.55 50555 mm .520 5055502 50> £0050505 52.55 50555 mm .5005. 5055052 50> £0050505 52.55 0.50 55 mm .5000 5505502 50> £0050505 52.55 50555 mm .5005 550555035 50> £0050505 52.55 50555 mm .5005 550555035 50> £03505 52.55 0505.55 mm 500.5 50555052 50> 400050505 52.55 0.50550 mm . . . . . . . . . . 05555 5300M 5555.5 £50550 mm . . . . . . . . . . $5555 535w 5555.5 £50550 mm . . . . . . . . . . 05555 0320 >555 £50550 mm . . . . . . . . . . 05555 58000 5555.5 £50550 mm . . . . . . . . . . £5555 0320 D555 £50550 mm . . . . . . . . . . 05555 5305M 55555 £50550 mm . . . . . . . . . . 05555 5520 >555» £50550 mm . . . . . . . . . . 05555 5305M 5555.5 £50550 mm . - . . . . . . . . . . . . . Y-ghavnw HNQ EQR.# HUQ.~= .< . . . . . . . . . . . . . . . . .=-OU Hmwmw 80.3% WH~§U§ w . . . . . . . . . . . . . . . . .QHQU hNQ EO.~% Mwwfiwv: ..€\ . . . . . . . . . . . . . . . . .=H°U HUU EQ¢~% KN§.~: .<1 . . . . . . . . . . . . . . . . . . . .:°@H~° Envvfw HU§.~= -< .. 40.050050 mm . . . . . . . . . . . . . .5500 500.5 500.5 050055. 5. . . . . . . . . . . . . . .. 1.500 500 5005 0.550% .5\ . . . . . . . . . . . . . . . ....055005 50.5 500.5 5x . . . . . . . . . . . . . . 11250550 50.5 500.5 .5.» . . . ihOfi-OO 60.5w 000.5 . . . . . . . . . . . . . . . . . . 5.5.500 5N0 80.: NU§.~Q . . . . . . . . . . . . 0505950505 50.55 505.5 . . . . . . . . . . . . . .05050._w0505 5005 500.5 - - . . . ~ - - . . . . . . - - - . - . . . . - . . - - . - - - - . - . . | . . . . - - - a n n - . . . . . . . . . . . . . . . . .k@U CHOU Envh.% NNQ-zh . 5 0 <<<<< 0 5 . . . . . . . .5555 50550 50.5.5 500.5 . . . . . . . . . . . . Z1500 5.50 500.5 05505075 . . . . . . . . . . . . . .5000 50005 50.5.5 0550i Aw 18 TEXAS AGRICULTURAL "EXPERIMENT STATION. AIR AND DUST CARRIERS OF ASPERGILLUS SPORES. From the foregoing discussion, it is evident that the boll Worm or corn-ear worm and possibly other insects not experimented With, not only open the Way to Aspergillus infection, but that they are also carriers of the spores of these fungi. These Worms undoubtedly gather the spores from the dust on the plant With which their bodies come in con- tact. That dust does contain spores of Aspergillus Was proved by the following experiment: Immediately after a wind storm, dust Was carefully gathered, With a sterilized camePs hair brush, into a sterilized test tube, from various foliage of truck plants in the garden, more especially from corn, tomatoes and beans. Some of this dust was then plated out in the usual way and, among the numerous organisms which appeared in the plate cultures, at least one-fifth of the growth was Asper- gillus. Furthermore, the air itself carries with it among many other organisms, spores of Aspergillus niger as well as A. flaws. To deter- mine this, 5O poured petri plates were made and after properly cooling and solidifying, were taken out in the open and the lids removed for one-half minute. After a period of 24 hours incubation, these plates showed a varied mycological flora, among which was also Aspergtllus niger as Well as A. flaous. From this it is easy to realize that as soon as Worms cause an injury to the corn ears or to any other plant mate- rial Which they attack, a way is opened to p-ossible secondary infection from Aspergillus and other fungi. With the yellow mold, A. flavus, as already stated, the fungus seems to attack only the tips 0f ears of those varieties which grow upright. In this case it is very easy for deW or rain water to lodge in the husk, and any spores of Aspiergillus flavus which may have been introduced with the dust Will find an ideal medium to start growth. SUSGEPTIBLE HOSTS. ' As already referred to on page 3, and from a study of Table 6, it Will be seen that besides the corn and broom corn, both zEiSPGTQiZZUS niger and A. flavus are capable of infecting a large number of hosts. Mention has already been made (5, 18, 19, 20, 24, 33, 3'7, and 38) that Aspergillus niger is responsible for diseases on various plants. In Texas the pomegranate is seriously attacked by Aspergillus, but this fruit is not grown to any extent to make it of sufficient economic importance. Nevertheless, the plant is grown for ornamental purposes on a scale large enough to Warrant consideration. During dry seasons, and as soon as the p-omegranates become partly mature, a large percentage of them split open and immediately rot from Aspergillus (Figure 4, a and b). The splitting of the fruit is common during dry Weather. The Aspergillus fungus, no doubt, enters the fruit through mechanical or insect injury. As regards the onion, Aspergillus niger is of consid- erable economic importance in Texas. This is true not so much as a field trouble but more so in storage or in transit. The disease is espe- cially serious on the large Spanish type of Denia onions. The black mold first appears as blackened areas on the upper two or three layers of the bulb scales (Figure 4, e), When carefully examining these dark areas, one will find that they consist of deadened tissue, the surface of which has been blackened With loose spores of Aspergillus niger. As the diseased area increases, larger numbers of the bulb scales become A STUDY OF BLACK AND YELLOW MoLns OF EAR CORN. 19 FIGURE 4. a. Healthy pomegranate. b. Pomegranate affected by black mold (natural infection). c. Peach_ artificially inoculated with Aspergillus niger. d. and f. Peach fruit destroyed by A. niger 1n transit. e. Young onion bulbs spotted by A. niger. g. Young bee colony the larvae of which were apparently killed by A. niger and A. flavus. 20 TExAs AGRICULTURAL EXPERIMENT STATION. involved and in time the entire onion shrivels and blackens and is then worthless. Frequently, also, a soft rot follows the opening ma.de by Aspergillus niger in which case the bulb rapidly soft-rots. The black mold of onions is seldom serious in the field under Laredo conditions, but it is severe when the crop is dug during a wet spell and when shipped under poor conditions of ventilation. Onions dug during wet weather become gorged with moisture and it is such bulbs that are very» susceptible- to the black mold. According to Wayne (37 and 38), Aspergillus niger inOhio attacks not only the mature onions, but also causes considerable damage to both seeds and sets. This, as already stated, is not the case in Texas and it is probably due to our peculiar spil and climatic conditions, which are different from those of Ohio. - “On the peanut, black mold does not seem to be of any importance as a field disease in Texas. It often, however, causes serious loss in: storage or in transit. With this crop, black mold is to be looked for when the peanut crop is harvested and given no opportunity to dry properly before it is stored or shipped. Numerous instances have come to the attention; of the author wherein car loads of shipped peanuts have been spoiled during transit and in such cases it has been determined that the peanuts were not properly dried prior to loading and shipping. Here the exterior of the peanut shells becomes blackened and coated with a dark powder which consists of the spores of Aépergillus niger. In extreme cases, the causal fungus also invades the inside of the nuts, causing them to blacken and to shrivel thus becoming unfit for seed or for oil purposes. In general, however, oil mills refuse altogether to accept peanuts which show infection on the exterior of the hull. l Although of no considerable economic importance, Aspiergillus niger if frequently found to injure Irish potatoes in Texas, causing a semi-dry rot. Here the fungus seems able to penetrate the tuber only through a cut or bruise and it frequently becomes serious in transit or under p-oor storage conditions. In referring to Table 6, one will see that under laboratory conditions. Aspergillus is able to cause a rot on de- tached bean and pea pods, as well as on apples, peaches, (Figure 4, c, d and f), plums, and carrots (Figure 5, h). In the field, it is not uncommon to find pea pods (Figure 5, c) especially those of black-eyed peas and bean pods (Figure 5, d and e), thoroughly rotted by Asper- gillm niiger. In this case, however, the fungus is- not able to attack sound pods but only follows insect injury, especially that of the boll worm, which, in Texas, feeds on a large number of hosts. As to peaches, the author does not know of a single case wherein Aspergillus niger was found to cause a rot on- peaches in the orchard, although it commonly follows brown rot, Sclerotinia fructigena, in transit. Never- theless, as seen from Table 6 and Figure 4, c, d, and f, Asgrerg/illus niger will readily grow on green as well as on mature detached peaches and cause them to rot. Infected peaches are at first water-soaked and then shrink and become blackened. Frequently the fruit melts away, owing no doubt, to the invasion of secondary organisms. The same is true of apples, which become rotted although the tissue remains more or less firm and the fungus seems to fruit more in the interior of the tissue than on the outside. This does not seem the case with the affected peaches as the fungus fruits abundantly on- the outer surface of the fruit only. From a- consideration of the trucking industry, A. niger is economically important in the sense that it produces a. serious rot of squashes and pumpkins in the field. Affected squashes become soft- A STUDY OF BLACK AND YELLOW MoLns OF EAR CoRN. 21 FIGURE 5. A. flavus o_n hard potato agar. b. A. flqvus on hard_bean agalr. c. Garden pea pod grtificjally inoc- ed by A. mger. d. Bea_n pod grtlfiqally moculated w1_th A. mger. e. Boan. pod_art1fic1al1y lnoculgted Lflavus. f. Tomato frult artlficxally lnoculated by A. Inger. h. k arrot art1fic1ally lnoculated by A. nlger. 22 TEXAs AGRICULTURAL EXPERIMENT STATION. rotted, water-soaked, and in a day or two are black, owing to the appearance of thefruiting heads of the fungus. Infection, no doubt, follows insect injury or starts on the dead corolla where A. mlger begins as a saprophyte and Winds up as a parasite. Not only does the Aspergillus group contain species which are harm- ful to plants, but there are also those which are capable of producing serious diseases in farm animals. According to Mayo (23) Enzootic cerebritis of horses in Kansas is attributed to Aspergillus gZau-cus. This is likewise supported by Dalrymple (9) and by Schoenleber (32), who claim that cerebritis of horses is probably the result of feeding moldy corn which is afiected with Aspergillus glauous. Haslam (17) claims that blind staggers (Meningoeucephalitis) in Kansas is caused by feeding moldy corn. Bayer (1) cites a case of cattle poisoning due to feeding of moldy clover invaded by Aspergillus glaucus. Pearson and Ravenel (2’7)_ report a case of Pneumomycosis due to Aspiergillus fumi- gaitus. Mohler and Buckley (26) report a case of pulmonary mycosis on birds attributed to Aspergillus fumigatus. They also claim that this same fungus would cause a disease in chickens, pigeons, rabbits,-and guinea pigs. Likewise, Savouré (30) attributes a_ serious tubercular lesion (internal mycosis) in animals, to Aspergillzts fumigatus, A. oryzae, and A. sulphurus. Likewise, Bodin and Savouré (4) claim to have tested out Aspiergillus fumigatus, Aspergillus niger and Sterigmatocystis pseudonigra on guinea pigs and found that A. fumigatus alone was pathogenic. Moreover, Sartory and Jourde (29) also found Aspergillus fumigatus and Sterigmatocystis spp. to be pathogenic to rabbits. It is interesting to note in this connection that the pathogenicity of some species of Aspergillus may be utilized in the control of insect pests. Valerio and Jongh (10 and 11) have tested out the effect of Aspergillus niiger and Asperg/illus glauicus on the control of mosquito larvae, CuleX and Anapheles. They found that species of Aspergillus were pathogenic to mo-squito larvae, but that in practice it did not pay to use these organisms on a large scale. Garrett (13) found an Asper- gillus species to be pathogenic on the sugar cane mealy bug (Pseudo- cocous cialceolariae) in Louisiana. Harshberger (16) states that Aspar- gillus flaous is capable of causing a disease on silk worm cocoons. In Texas, the author has repeatedly isolated Aspergillus niger and Aspar- gillus flavus from dead bee larvae obtained from diseased bee hives (Figure 4, g). The pathogenicity of these two organisms on bees, how- ever, was not tried out. Gilruth (14) rep-orts a red discoloration of butter due to Asperrgillus nidulans. Likewise, Butjagin (6) reports the spoiling of meat due to Aspergillus niger. From the above discussion of the literature, it is seen that there are strong evidences that Aspergillus glaucus is the cause of serious com- plications in animals and in but one instance is it claimed specifically that A. niger induces a disease on mosquito larvae. Inasmuch as the black mold of ear corn and broom corn i11 Texas is caused by Aspergifllus WtQOT, it isinot certain whether such corn, when fed to horses, would bring about a disease similar to that produced by Aspergillus glaucus, as is reported by Mayo (23) and others to occur in Kansas. This being a veterinary question, no attempt was made, t0 determine the effect of feeding blackmoldy corn to horses. The author, however, may state definitely that he has fed corn infected with black mold to adult _. chickens ‘for more than two months WltllOllt any apparent harmful if A STUDY or BLAoK Ann YELLOW MoLDs or EAR CORN. 23 effect to their health. The general belief among farmers is that when moldy corn is fed to horses, it will give them the heaves. Others claim that it will be the cause of serious coughs. The author takes no re- spon.sibility for these statements. Beed and Barber (28) express the belief that Aspergillus fumigatus is not responsible for stock poisoning when this fungus occurs on moldy silage. PH1YSIOLOGIC=AL SPECIES . It has already been stated that the black mold of corn is caused by a fungus, Aspergillus nligev", which can gain entrance to the ear only through a puncture and especially when the ear is in its milky stage. In the field, the injury which favors infection is that caused by the corn-ear worm and other agencies mentioned on pages 15 and 18. It has been further stated that Aspergillus niger also causes a mold on peanuts, onions, and other crops. The author has repeatedly isolated Aspergillus ' niger not only from ea.r corn, but also from peanuts, cotton bolls, cowpea pods, onions, pomegranates, lrish potato tubers, squashes and broom corn. It became necessary, therefore, to determine Whether or not strains of the black Aspergillus isolated from the various hosts mentioned above are distinct or physiological species, or whether they are one and the same as Aspergillus niger, which causes the black mold of corn. Ac- cordingly, strains isolated from the above hosts were inoculated in ear corn, the method of inoculation being indicated in Table 6, which . shows that strains of Aspergillus niger isolated from peanuts, onions, pomegranates, cotton bolls, cowpeas, Irish potatoes, squashes and broom corn will produce a black mold on ear corn when inoculated in its milky stage as readily as will the strain of Aspergillus isolated from the ear corn itself. This seems to prove that there does not exist any physiological species or strains in the fungus known as Aspergillus niger. CONDITIONS FAVORING INFECTION. It has been. made clear that ear mold of corn is caused by the fungus Asperg/illus niger and that this organism can only invade the ear during its milky stage and when it. has been injured by the ea.r worm. Since black mold in the field depends primarily on the injury of the ear worm or other insects, it follows therefore that the severity of the black mold will be correlated with the severity of the presence of the» ear worm. Garman and Jewett (12) claim that the ear worm is not as common in some seasons as it is in others. It may, in fact, be prevalent in one locality one season and yet be practically rare another season. This seems to be the condition in Texas, where the ear worm is more preva- lent during dry seasons. During 1917 and 1918, two dry summers, the ear worn was unusually severe and as a result, the injury from the black mold of corn was in the same proportion. On the other hand, during ‘ 1919, which was practically a Wet season, there was very little ear worm and consequently correspondingly very little black mold. Bishop (3), on the other hand, states that throughout the entire country '70 to 90 per cent. of the ears of field corn: are attacked (referring to the ear- Worm). Following this injury, molds frequently gain access to the ears and ‘damage them still further. This is especially true during wet seasons. Bishop does not state which molds he has in mind. It is, of course, conceivable that during wet weather, various molds should 24 a TEXAS AGRICULTURAL EXPERIMENT STATION. attack corn ears which were previously injured by the ear worm 0r by other insects. As far as the black mo-ld of corn is concerned, dry- weather conditions do not prevent infection of Aspergillus niger, since the latter directly follows the injury made by the ear worm. It seems plain. that the greatest amount of black mold of corn should be looked for during dry seasons. Moreover, during wet we-ather, the co-rn—ear worm, although prevalent, is parasitized by numerous other insects and fungi which tend to keep it in check. This also indirectly results in reduced losses from black mold. As to the yellow mold, as already stated, infection depends directly on the amount of moisture which is able to collect at the tip end of the ear as "it stands erect on the stalk. 25 A STUDY OF BLACK AND YELLOW MOLDS OF EAR CORN. flow 5 woxho? CB: A.» .3 muhoam Mo htwqasv .53 >513: 53h . . . . . . . 5cm E wvxao? sou wcsouw >513: duo hstmo: 52h . . éouiéowz: wan wfivfihnm .:m5m 552m duo wofiofi: Zwmm .$u.5 wzzwuémwfl 53 wuwmz: 3355a was wonoxfiin new 5Q _ME.~OG Zwcobwaam 312m 53 wowoofifi ~¢-¢--...»-» - - - . - - . .-..-----»-m-HN®%:€@“QAE°-Mm , $535 was M5323» 635:3 w55ooon “Eu an 125.8: wmczwuow oofi om w 3250 >532 $>o 503x35? @2238. ooH om N“ 6mm wzfi. 5w pm mcrnw J13? mmcswoww Q 3 N om wv $53. was @355.“ M55035 mzmswcu>w ~13? mwczwuwm wv om z . ._m5~oZ o2 on 2 533920 we 525M GOSNGUMZUU 5cm $5 uwvm mEiP we Mo 58 5am we 5:522 502522 wwow .8 ofisom doom Eco >305 was amino: we gbobmlkh QEFH FIGURE 6. a. Check pot planted with healthy corn seed. b. Pot planted with corn seed taken from an apparently healthy ear but with cob affected by A. niger. c. Pot planted with seed from a badly blackened ear in which both cob and seed were invaded by A. niger. d. Pot planted with healthy seed in which crushed up cob from a healthy ear was worked in. _ e. Pot planted with healthy corn_ seed in which crushed cob from a diseased ear was worked 1n. f, g, h, z and i. The same as a, b, c, d and e except that the plantsare one week older. Notice the weakseedlings in pot g. and the same 1n pot h. There seems also a slight stimulation in pot i. and a checking of rowth 1n pot 1. k, I, m, n, and 0, the same as f, g, h, i, and i, except _t at the plants are two weeks older. Notice the healthy check plants 1n pot k and decided stimulation of growth in pot n, and the dying of the plants in pots l, m, and o. A STUDY or BLACK AND YELLOW MoLns or EAR CoRN. 27 . USE OF BLACK MOLDY SEED CORN. It has been frequently asked Whether or not it is safe to plant corn affected with black mold. Experiments have been carried out to de- termine Whether or not such a practice is desirable or safe. It is taken for granted that no one will ever use seed corn that cam-e from badly diseased and shriveled ears. Nevertheless, there are cases of late infection, Where the ears were but slightly injured by the black mold, infection being confined to the place of injury from the ear worm and resulting in an ear more or less normally developed and apparently containing well nourished and fully developed grains, although their surface may be covered with spores of Aspiergillus niger. The ques- tion Ihight, therefore", be asked whether such gra.ins are safe for plant- ing purposes. To determine this the following experiments Were plan- ned: Seed from moldy corn was secured from various sources and arranged as follows: (1) seeds from healthy ears; (2) seed corn apparently normal, but taken from an ear Whose cob was thoroughly blackened and invaded by Aspergillus niger; (3) seed corn taken from ears which were badly affected and shriveled as a result of black mold. The seeds from these three sources were each planted separately in pots in order t-o determine their germination. In connection with this, healthy seed corn was planted in pots into which was Worked healthy ground cob. Finally m-ore healthyseed corn was secured and planted in pots in soil into which was worked a large amount of spores of Aspergillzas n-iger secured from diseased ear corn. The results of this experiment are shown in Table 7. In studying Table 7 and in referring to Figure 6, a to e, one will see that check pot Figure- 6 a was normal in germination. In pot b, germination was normal, but the seedlings were Weak. In pct c, the germination was poor and there Was a very weak stand; pot d, normal germination. and apparent slight stimula- tion ; pot e, normal germination and apparent slight stimulation in some of the seedlings. In further reference to Figure‘ 6, f to j, it is seen that as the seedlings progressed in age, they lagged in pot g, while those in pot h Were decidedly dwarfed. The seedlings in pot i Were apparently‘ the strongest of all, owing, it seems, to the addition of the ground healthy corn cob. Whether the cob in this case acted as a fertilizer or not has not been determined. In further reference to Figure, 6 k to o,. it is seen that the check in pot k made considerable headway and the- plants in pot n were still leading. On the other hand, the seedlings- in pots l and m were practically dead, whereas seedlings in pot o were partly dead. This clearly demonstrates that for seed purposes, only grains from healthy ears should be secured. Furthermore, no matter how sound a. grain appears, it should never be taken for seed if it came from an ear which had the least infection or if the cob has been decayed from black mold. . Furthermore, at no time should seed corn be taken from badly diseased ears, as in this case not only will the germination be very inferior, but the few seed that will germinate will produce weak plants which will eventually die. Finally, when spores of Aspar- gillus niger or black powder residue from diseased black moldy corn, is added to the soil, the grain corn although healthy when planted will result in Weak seedlings which eventually die from rotting of the roots by Asprergillus niger. This was the case when the roots of the plants from pot o were examined. It was found that most of them were destroyed and blackened and, upon culturing, proved to be Aspergillus 28 TEXAS AGRICULTURAL EXPERIMENT STATION. niger. As a conclusion, it must therefore be definitely stated that for seed purposes, only healthy seed of absolutely healthy ears should be secured. . SYSTEMATIC RELATIONSHIP. In dealing with so variable a group of fungi as Aspergillus it is necessary to define the gene-ric relationship of the two species, Asper- gillus niger and A. flamts, with which the present bulletin is concerned. In studying over the literature on Aspergillus, we find that Van Tieg- hem (39) has accepted the name of Aspergillus niger for the black species of Aspergillus. That Aspergillus was confused with other fungi, especially with Ascophora, was due mainly to a misconception of some French mycologists who preceded Van Tieghem. Fortunately, however, the studies of Robin and others on Aspergillus species which cause ear diseases in humans, have led up to the possibility of distinctly separating the black species of Aspergillus from the black Mucors. Cramer (7) named some forms of Aspergillus, Sterigmatocystis. The author agrees with Thom (36) that there is nothing to justify the exist- ence of the separate generic name of Sterigmatocystis and that all species of that genus should be referred to as Aspergillus. In our present Work, all species of Sterigmatocystis are referred to as Asper- gillus. [According to Thom’s classification of the black Aspergillus group, which the Writer accepts as correct, Aspiergillus niger is a form with both primary and secondary sterigmata, the primary sterigmata being 20-30 u in length] In referring to page 18 we will see that McMurran (24) as well as Hodgson (18 to 20) mention a pomegranate rot due to Sterigmatocystis castan-ea. The Aspergillus fungus which attacks pomegranates in Texas does not seem to differ from Asper- gillus niger, which we- have repeatedly isolated from ear mold of corn and both of which readily cross from one host to the other. Hence, as already stated, the genus Sterigmatocystis is untenable and the fungus which causes the rot of pomegranates in Texas is referred to in this work as Aspergillus niger. The same is also true for the strains of black Aspergillus isolated from cotton bolls, peanut, squash, black-eyed pea pods, Irish potato tubers, and dead bee larvae. All of the species are morphologically similar. As to the yellow Aspergillus, namely, A. flavus Link, it is believed that its generic and specific relationship requires no mo-dificatio-n. CULTURE WORK. All the strains of Aspergillus mentioned in the previous discussion were at first grown on a variety of media. The writer has, however, finally decided on two media, namely, hard potato agar and hard bean agar*. Numerous strains were tried out as to their morphology and physiology. In referring to Figure '7, a to g, we will see that three-day-old plate cultures of Aspergillusrziger from squash, onion, corn, peanuts, and cotton, on hard potato agar, showed practically no morphological dif- ference in growth. Young colonies of these strains, as is seen from *By hard agar is here meant the addition of 30 grams of agar agar to each 1,000 cc. of media. A STUDY OF BLACK AND YELLOW MOLDS OF EAR CoRN. 29 ' FIGURE 7. Young plate cultures on hard potato agar of: a_. Aspergillus niger frpm cotton bolls. b. A. niger fro_m w onlon bulbs. c. A. nzger from ear corn‘ A. nzger from squash frult. e. A. mger from peanut frult. '1 .A. flavus from ear corn. g. A. flavus from dead bee larvae, 3O TEXAS AGRICULTURAL EXPERIMENT STATION. ».,..¢@..<4_...< L. s. xi.“ r 1.‘. m. .< “ "“‘ - FIGURE 8. a. and b. Advanced plate cultures of Aspergillus niger from onion bulb. To the left, on hard potato agar. To the right, on hard bean agar. c. and d. Advanced plate cultures of A. niger from cotton bolls. To the left, on hard potato agar. To the rlght, on hard bean agar. e. and f. A. flavus from broom corn. To t e left, on hard potato agar. To the right, on hard bean agar. A STUDY or BLACK AND YELLoW MoLns OF EAR OoRN. 31 Figure '7, a to e, are compactly zonate with dense numbers of fruiting heads. Likewise, as is seen from Figure 7, f and g, young colonies of Aspergillus flamus, isolated-from yell-ow mold of corn, and from dead bee larvae, alike, 0n hard potato agar are distinctly zonate a.nd the growth not as dense as is the case with Aspergillus niger. As the col- onies of A. niger increase in age, growth becomes more distinctly zonate with a formation of an abundance of spore heads on potato agar. On bean agar, growth is more luxuriant and more distinctly zonate, but with smaller numbers of fruiting heads in the zones (see Figure 8, a to .f). Finally, as the same plate cultures become ten to fifteen days “old, the outer edge of the colonies on potato agar ceases apparently to zonate, growth becoming irregular, and spore-production apparently ceases or becomes scarce (Figure 9, a to f). This, however, is not the case with the same older strains when grown on bean agar and as seen in Figure 8 (compare a, c, and e to l, d and_ f). Likexvise, older cul- tures of Aspergillus flavus become more intensely zonate on the potato agar but less so on bean agar as seen in Figure 5, a and b. During the course of our culture work, it was noticed that whenever two different colonies of Aspergillus niger and A. flrwus grew near each other, a dis- tinct inhibition line became apparent, preventing the two colonies from meeting and leaving a distinct line of demarcation between the mar- ginal ends (Figure 10, a to e). This line persisted for a long time, often as long as 10 to 15 weeks, but finally the borders of the colonies would gradually intermix. Similar observations were made by Zeller (41) who found the same tendency of colonies of A, niger to repel each other. - OTHER DISEASES OF EAR CORN AND BROOM CORN To clearly distinguish between the black and. the yellow molds of ear corn considered in the present bulletin, it is necessary to briefly men- tion the other diseases with which these two molds are frequently con- fused. a. Corn Smut. This is a true smut and is caused by a fungus [Tstilago Zeae (Beck) Ung. Corn smut attacks all parts of the plant abo-ve ground, namely, leaves, stalks, tassels, and ears. It is recognized as soft boils of various sizesespecially on the tassels and ears, in which case the male elements, or the grains in the ears, are replaced by large soft bluish-colored swellings. These when ripe crack open and liberate a black dust which constitutes the spores of the causal fungus. Corn smut cannot be controlled by any method of ‘seed treatment because the fungus is carried over in the soil from year to year and infection does not take place when the corn seed germinate in the soil, but occurs when the plant is in a growing condition and the tissue more or less soft and tender. As already stated, when the smut boils break open, the black, dusty powder is shed on the ear giving it a. black, smutty appearance. It is this stage which is likely to be confused with the black mold of ear corn,* the symptoms of which are given on page 5. Of the diseases which ‘attack broom corn and which may be mis- taken for the black mold should be mentioned head smut, which is causedvbyv a fungus Sorosporiurwz reilianunt (Kuhn) McAlp. This *For a descriptioniof corn diseases other than black mold, see (35). 32 TEXAS AGRICULTURAL EXPERIMENT STATION. FIGURE 9. a. and b. Old plate cultures of A. niger from squash fruit. To the left, on hard potato agar c. and d. Advanced plate cultures of A. niger from ear corn. To the left, on hard potato agar To the right, on hard bean agar. e. and f. Advanced plate cultures of A. niger from peanut fruit. To the left, on hard potato agar. To the right, on hard bean agar. g) A STUDY or BLACK AND YELLOW MoLDs OF EAR CORN. 33 FIGURE 10. a. Numer 11s colonies of A. niger from ear corn. To the left, on hard potato agar. To the right, on hard bean agar showing a tendency for the colonies to keep away from each other. b. Same as a. on hard bean agar. c. Small colony of‘ A. flavus and a large colony of A. niger growing in the same petri dish on hard potato agar with the same tendency of the two colomes keeping away from each other. e. Same as a. d. Showing a small yeast colony next to a large colony of A. flvvus, the former prohibiting the encroachment of the latter. 34. TEXAS AGRICULTURAL EXPERIMENT STATION. smut is very prevalent in northwest Texas and is easily distinguished because it is confined to- the head which becomes a soft mass of smutty dust; in this- respect some-what resembling true corn smut. Kafir, broom corn, and sorghums are very susceptible to head smut, while the milo seems to be free from it. Like corn smut, head smut of broom cor cannot be controlled by any form of seed treatment. ' Another smut which attacks broom corn is that known as kernel smut and is induced by two species of fungi, namely: Sp-hacelotlzeca sorghi (Lk.) Cl. and Sphacelotheca cruenta (Kuhn) Potter. Kafir, sorgos, broomcorn, and Sudan grass are subject to this smut. Infected heads bear a great number of false kernels, which are filled with a mass of black dust consisting of the spores of the causal organism. Kernel smut may be controlled by soaking the seed f-or two hours in a solution of formaldehyde made up of one p-int in. 30 gallons of water, or by soaking the seed 1O to 12 minutes in hot water at a. temperature of 142 to 143 degrees Fahrenheit. ixrnrrrons or‘ CONTROL. From the foregoing discussion, it becomes evident that b-lack mold of corn is dependent directly on insect injury to be able to attack the corn ears. Furthermore, infection is only possible during the milky stage of the ears. Hence control methods for the black mold of ear corn is mainly a problem for theentomologist and the plant breeder; i. e., it is necessary to keep the ear worm in check through cultural methods, and in develop- ing resistant varieties. It seems that some varieties are less attractive" to the ear worm and hence are freer from black mold than others. These varieties of corn m-ay be mentioned as Improved Indian Squaw and Surecropper. These two varieties seem also to be ‘more resistant to the _vellow mold. Collins and Kempton (8), in breeding sweet corn resistant to the corn-ear wrorm, have been able to show that a resistant strain‘ of sweet corn may be developed by crossing so as to increase the length and thickness of the husk covering, at the same time reducing the husk leaves. This was accomplished by hybridiza- tion and selection of desired plant characters as already stated. To control _vellow m-old one has only to plant those varieties of corn that have pendant ears. To do so is especially important in localities with heavy rainfall. ' Both the black and the yellow molds on broom corn are also amenable to treatment. Investigations by the Division of Agronomy of the Texas Agricultural Experiment Station have shown that broom corn molds in general, whether black, yrelloyv or white, are more severe on varieties which lack in length of the peduncle. Selections made in this direction have resulted in better broom corn, seeds of which the Division of Agron- omy is now ready to distribute to farmers of Texas. REFERENCE. (1) Bayer. Poisoning of cattle by molds. Wchuschr. Tierheilk u. Viehzucht 49 z793-794, 1905. It is reported that cattle were killed by eating moldy clover covered by .4.sperg1TZZus glazzcus and penicillin/m giaucum... (2) Beille. L. Changes in coffee grains due to Aspergillus. Proc. Verb. Soc. Sci. Phys. et Nat. Bordeaux: 37-38, 1912-1913. ‘ A STUDY or BLACK AND YELLOW MoLDs OF EAR CoRN. 35 Stinking rot of coffee grains induced by Aspergillus nigez‘ and Aspar- gillus flavus. (3) Bishop, F. S. The boll worm or corn-ear worm. U. S. Dept. of Agr. Farmers’ Bul. 872:3-15, 1917. Studies Were made of the corn-ear worm and the fact is recognized that this worm opens up the way to injury from mold fungi. (4) Bodin, E, and Savouré, P. Internal mycoses. Arch. Par. 83110-136, 1904. AlSfVZVQfZZUS fuimigatus, A. iviger and Sterigmatocystis piseudoniigra were inoculated in guinea pigs to test their pathogenicity. Aspergillus . fltmigatuis responded affirmatively. (5) Brooks, C., Fischer, S., and Cooley, J. S. Apple rots (Abstract) Phytopath. 4:403, 1914. Of the many fungi isolated from diseased market and storage apples. Aspergillus niger was one of them. (6) Butjagin, P. W. The chemical changes of meat brought about by mold. Arch. Hyg. 5231-21, 1905. Aspergillus niger and Penicillivim glaucum are reported to be the cause of the spoiling of meat. (7) Cramer, Carl Weber. Eine neue Fadenpilzgattung Sterigma- tocystis. Vrtljschr. Naturf. Gessell, Zurich, Jahrg. 4:325-337, 1859. (8) Collins, G. N, and Kempton, J. H. Breeding sweet corn re- sistant to the corn-ear Worm. U. S. Dept. of Agr. Jo-ur. Agr. Research, 111549-572, 1917. illention is made of the fact that it is possible to breed through cross; ing, strains of sweet corn resistant to the ear worm. (9) Dalrymple, W. H. Report of the Veterinarian. La. Agr. Expt. Sta. Bul. 22, 2d series :724-730, 1893. Cerebritis of horses supposed to be due to the feeding of moldy corn affected with Aspiergillus glaucus. (10) Galli-Valerio, B., and Jeanne Bochaz-de Jongh. The effect of AspergiZZusWz-iger and A. glttucus on the larvae of Culex and Anapheles. Centbl. Bakt. 1 Abt. Orig. 38174-177, 1905. (11) -—-—~—————— -— The action of Aspiergillus niger and A. glaucus 0n the larvae of Culex and Anapheles. Centbl. Bakt. 1 Abt. Orig. 401630-033, 1905. Alspergillus niger and A. gla-ucus are claimed to be pathogenic to mosquito larvae ; however, it was not thought practical to use these two fungi for the treatment of marshes and stagnant water where mos- quitoes are breeding. (12) Garman, H., and Jewett, H. H. The life history and habits of the corn-ear worm (Cider/idea obsoleta) Kentucky Agr. Expt. Sta. Bul. 1873513-591, 1914. A careful study is made of the corn-ear worm injury. The author claims that the worm is responsible for opening up the way to injury from various mold fungi. A (13) Garret, J. B. The sugar cane mealy bug (Pseudococcus cal- ceolariae). La. Agr. Expt. Sta. Bul. 121 :3-19, 1910. A species of Aspergillus was found to parasitize the mealy bug in Louisiana. 1 (14) Gilruth, J. A. Beport of the Division of the Veterinary Science in New Zealand. Dept. of Agr. Bept, zl90-336, 1903. 36 c TEXAS AGRICULTURAL EXPERIMENT STATION. Aspergillus nidulans causing a red discoloration of butter. (15) Hanzawa, J. Fungi and composition of Japanese Tamari Ko-jii. Mycol. Centbl. 1:163-166, 1912. Tamari Kojii is a. Japanese soy bean sauce in which Aspergillus oryzae is the chief fermentative agent. (16) Harshberger, J . W. A text book of Mycology and Plant Pathology, 1917. Blakiston Son and Company, Philadelphia, Pa. Aspergillus flcwus the cause of a disease of silk worm cocoons. (17) Haslam, T. P. Meningo Encephalitis (blind staggers). Kan- - sas Agr. EXpt. Sta. Bul. 1731235-251, 1910. _ Blind staggers in horses in Kansas is apparently caused by feeding corn infected with Aspergillus glaucus. This inferior corn is prevalent in dry weather and is also insect-eaten. (18) Hodgson, B. W. Pomegranate. Cal. Agr. Expt. Sta. Bul. 2761163-192, 1917. Mention is made of Sterigmatocystis castanea Patt. as causing a heart rot of pomegranate. (19) ———————-—~—. Sterigmatocystis smut of figs._ Phytopath. 81545-540, 191s. The White Adriatic fig in California subject to an internal black smut caused by Sterigmatocystis. Infection is claimed to be favored by insects. (20) ———--———. Black smut of figs. Monthly Bul. State a Comm. of Hort. Cal. 7188-189, 1918. A general discussion of black smut oflfigs is given. (21) Kopeloff, Nicholas, and Ko-peloff, Lillian. Deterioration of sugar by fungi. La. Agr. Expt. Sta. Bul. 166 z3-72, 1919. Studies made of the deterioration of cane sugar by fungi, among which Aspergillus plays an important part. (22) ——9- -—- ——. The isolation of fungi from manufactured sugars. Phytopath. 1919. (23) Mayo, N. S. Enzootic cerebritis of horses. Kan. Agr. Expt. Sta. Bul. 241-12, 1891. _ Aspergillus glaucus is claimed to be the cause of mad staggers in horses, attacking the kidneys and liver. It seems that neither mules, cattle nor pigs are attacked by this disease. . (24) McMurran, S. M. A new internal Sterigmat-ocystis rot of pomegranates. Phytopath. 2125-126, 1912. Pomegranate disease found in California, Arizona and Texas due to- Sterigmatocystis castanea Patt. (25) -——_-. B111. Torr. Bot. 0111b 221284, 1900. a (26) Mo-hler, J. R, and Buckley, J. S. Pulmonary mycosis of birds with a report of a case in a. flamingo. U. S. Dept. of Agr. Bureau of Animal In. Bept, 1122-123, 1903. A flamingo bird in the National Zoological Park imp-orted from Cuba apparently killed by Aspergillus fumigatus. The same fungus inocu- lated into chickens, pigeons, rabbits, and guinea pigs proved fatal. (27) Pearson, L., and Ravenal, M. P. Pneumomycosis due to Aspergillus fumigatus. Jour. Comp. Med. and Vet. Arch. 21:451-465, 1909. Aspergillus fumigatus the cause of tuberculosis in cow. (28) Reed, G. M., and Barber, Lena. Micro-organisms in Silage. Mo. Agr. Expt. Sta. Bul. l47z29, 1917. A STUDY or BLACK AND YELLOW MOLDS or EAR OoRN. l 3'7 No evidence that Aspergillus fumigatus was responsible for stock poisoning from moldy silage. (29) Sartory and Jourde. Biologic and pathogenic properties of Sterigmatocystis Zu-tea. Oompt. Bend. Acad. Sci. (Paris) l46z548- 549, 190s. a Sterigmiatocystis lutea and Aspergillus fumigatus pathogenic to rab- bits. " i (30) Savouré, P. Internal mycoses and the micro-organisms which cause them. Arch. Par. 10:5'70, 1905. - Serious tubercular lesions are reported in animals and supposed to be caused by Aspergillus fumiigatus, A. oryzae, A. sulplhurus and other fungi. i (31) Shapovalov, M. Some potential parasites of the potato tuber. Phytopath. 9:36-42, 1919. » . Aspergillus niger a wound parasite on tubers of Irish potatoes. (32) Shoenleber, F. S. Loss of horses in Kansas. Industrialist 32:263-264, 1906. '1 It is reported that, in Kansas, horses were killed by being fed on moldy corn and fodder covered by a fungus, especially Aspergillus glaucus. ' - ‘ (33) Stevenson, J. A. Plant Diseases in‘ Porto Rico. Rept. Bd. Oomrs. Agr. P. R. 4:33-44, 1914-15. . Citrus fruit rots caused by many fungi, among which is mentioned Aspergillus niger. (34) Stoykowitch and Brocqrousseu. A study of some changes occurring in prunes. Rev. Gen. Bot. 22 z70-79, 1910. The deterioration of prunes by molds especially by Aspergillus and Penicillium glaucmn. These two fungi reducing the sugar and acid contents of the prunes. (35) Taubenhaus, J. J. Diseases of grains, sorghums, and millet and their control in Texas. Tex. Agr. Expt. Sta. Bul. 2613-34, 1920. (36) Thom, Charles. Aspergillus nigc-r group. U. S. Dept. of Agr. Jour. Agr. Research '7:1-15‘, 1916. A careful study was made of the Aspergillus niger group. 4 (37) Wayne, Van Pelt. A new fungous disease causing serious damage in storage houses. The Monthly Bul. Ohio Agri. Expt. Sta. 152-156, 1917. Aspergillus niger was recorded as causing a serious rot of stored onions. It is claimed that the spores of Aspergillus are carried on the seeds and if these seeds are planted untreated, their germination is greatly afiected, as much as 50 per cent. failing to come up. Seed treatment withformaldehyde is recommended. (38) Wayne, Van Pelt. Onion diseases as found in Ohio. ‘The Monthly Bul. Agr. Expt. Sta. 3:70-76, 1919. _ Onion mold in storage is attributed to Aspergillus niger causing a. black mold which is frequently mistaken for onion smut. The mold is now re- ported from Ohio, Virginia, Kentucky, New York, Illinois, and Califor- nia. As a control measure it is recommended that the seeds be drilled in a wet drill in which a. drip is attached which drips formaldehyde at the rate of one pint to 25 to 33 gallons of water. As for the onion sets, it is recommended that they be soaked for 6 hours in 1 pint of for- maldehyde to 33 gallons of water or soaked for 6 hours in a solution 38 TEXAS AGRICULTURAL EXPERIMENT STATIoN. made up of 1/2 pound of powdered calcium hypochlorite (ordinary bleaching powder) in one gallon of water. (39) Van Tieghem, P. E. L. Recherohes pour servir a Phistoire physiologique des Mucedinés fermentation gallique. Ann. Sci. Nat. Bot. s. 5t. 8 No. 4:240, 1867. (40) Wehmer, C. Aspergillus oryzge, the fungus of Japanese saki brewing. Centbl. Bakt. und. Par. Allg. 1:150-160 and 209-220, 1895. (41) Zeller, S. M., and Schmitz, H. Studies in ‘the Physiology of the Fungi (8 mixed cultures). Annals Mo. Bot. Gar. 6183-192, 1919.