A- a; an. tmanaasfi * :5 TEXAS AGRICULTURAL EIZPERIMENT STATION R. D. LEWIS, Director COLLEGE STATION, TEXAS BULLETIN 701 JULY 1948 ‘The Control of Transit and Storage Deeays in Texas Lemons .1-‘ 14,- < ¢' . w , ' ‘ , ,_r‘;, r‘ ~*-. ».. ‘I '-. .~ r‘ * ‘ > ~ ‘ ' G. H. GODFREY and A. L. RYALL l1 AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS a GIBB GILCHRIST, President J53-748-3M-L180 2 x ' § \: n- é: 4t P: 3 CONTENTS Page Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Tests With Soaps and Fruit Cleansers . . . . . . . . . . . . . . . . . . . . . . . .. 9 Stem-end Treatments With Chemicals . . . . . . . . . . . . . . . . . . . . . . . . .. 10 Fruit Dip Treatments With Chemicals . . . . . . . . . . . . . . . . . . . . . . . . .. 11 Borax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. l3 Sodium Metaborate (Metbor) .p . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13 Sodium Ortho-phenylphenate (Dowicide A) . . . . . . . . . . . . . . .. 14 v Ineffective Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 17 Diphenyl Tissue Wraps as Supplemental Treatment . . . . . . . . . . .. 17 The Control of Penicillium (Green Mold) Decay . . . . . . . . . . . . . . . .. 19 Diphenyl-Impregnated Tissue Wraps for Green Mold Control. . 20 Fumigation With Nitrogen Trichloride (Decco) . . . . . . . . . . . . . . . .. 21 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 24 ma? .Pnfi%ce _ Citrus fruits, particularly lemons and early oranges, are subject . to transit and storage decays. Sometimes when conditions are ;.i;very bad, decays range up to 85 percent g weeks after harvest. L» Stem-end decay caused principally by the fungus Diplodia nata- EQIensis is the principal source of loss from midsummer to late fall Ila-in the Lower Rio Grande Valley. The green mold, Penicillium l-Ttdigitatum, and to a less extent the blue mold, P. italicum, are the leading causes of decay in the winter months. . Experimental work conducted on lemons at the Lower Rio ‘Grande ValleyStation (Substation No. 15) from 193g to-1g46 lhas shown that these losses can be controlled, usually from o to 5 percent decay, by chemical dip treatments. Materials found gifective for the dip treatment are sodium metaborate (Metbor) Sat 5 percent concentration, and sodium ortho-phenylphenate :(D0wicide A) at 1.2 percent concentration, each with specific ualifications mentioned in the body of this bulletin. , The effectiveness of these chemicals in periods of high inci- aence of decay is increased by wrapping the fruits in diphenyl- pregnated tissue wraps. Control in such periods can also be creased by following the chemical dip treatment with exposure >0 0.03 parts per million nitrogen trichloride gas in the ethylene i is coloring room, or even in the car after loading (Decco l‘ rocess) . ' ‘ l. The series of experiments reported herein have consistently . ‘_ own that the serious losses frequently occurring in the ship- gents of non-treated fruit can be avoided by proper use of the “7 ommended treatments. 23§G'73 Figure 1. Stem-end rot, (Diplodia naitalensis) in Meyer lemons. A, an early stage, about 24 hours after the first symptom; an irregular tan discoloration, is barely evident extending i to é inch from the stem button. B, a more advanced stage with about half the fruit discolored in irregular bands which are usually slightly flattened. C, the entire fruit is involved, but the fruit is still intact; up to this stage there is no surface mold on the fruit. D, the fruit is entirely black and somewhat mummified; at this stage the spore-bearing bodies of the fungus may frequently be found imbedded in the rind in the form of very small globular bodies filled With the White spore mass. QLETIN 701 JULY 194s The Control of Transit and Storage Decoys l ' in Texas- Lemons .26 ,H. GODFREY, Plant Pathologist, Substation No. 15, Weslaco, Texas, and _A. L. RYALL, Horticulturist, Division of Fruits and Vegetable Crops and Diseases, Bureau of Plant Industry, Soils and é Agricultural Engineering, U. S. Department of Agriculture Stem-end rot, due chiefly t0 the fungus Diplodia mztalensis, has pg been the source 0f serious loss to citrus growers in the Lower i: Grande Valley 0f Texas. Lemons,‘ mostly of the Eureka and yer varieties maturing in-summer and fall, are particularly sub- to these losses (see Figures 1 and 2). Frequently, however, f; s are also encountered in early and late oranges and occasionally grapefruit. Blue and green molds (Penicillium italicum and P. tatum, respectively) sometimes cause large losses in transit and rage during winter (see Figure 3). ecay in citrus fruits has remained a serious problem to the i. ercial packer and shipper, to the broker at the terminal markets, ‘jthe retailer and to the ultimate consumer in spite of the routine llication of standard preventive measures. It is indirectly serious .,t_he grower in that any shipment of fruit from his territory that {elops a high percentage of decayed fruits causes consumer ill- and prejudice against fruit from that locality for a prolonged ‘iod, even though later shipments may be sound. ‘his bulletin reports the results of experiments performed by senior author from 1938 to 1942 and by the two authors jointly 3 1943 to 1946, directed toward the control of these losses in ‘ons. A few tests with oranges are also included. LITERATURE REVIEW is well established (7) that two distinct fungi, Diplodia natal- ,’ Pole-Evans and Diaport/ze eitri (Faw.) Wolf, produce stem- l’ rot, and that the symptoms produced are very similar—a fthery, pliable decaying area encircling the button or stem end, ‘a! colored to brown in color, gradually enlarging in area and i‘ ing darker in color until the entire fruit is involved. With lodiw, the rot culminates in a black color and complete mummifi- 7'0n of the fruit. It is known (2, 21, 23, 24) that with both fungi, l; stage is on dead wood in the tree, where, during a moist period, res are produced abundantly and are deposited on the fruit. Under lorable conditions the spores will germinate, and the hyphae BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION Figure 2. Stem-end rot (Diplodia natalensis) in Meyer lemons showing the advance of decay. The dark lines indicate the margin as it was 42 hours before the photograph was taken. The fruits were held"at room temperature (minimum, 76°, maximum, 96° F.) Sep- tember 10 to <12, 1947. Figure 3. Blue mold (Penicillium italicum) and green mold (Peni- cillium digita-tum) on Valencia oranges. A, blue mold; note the dark spore-bearing central region surrounded by a rather narrow white belt of fungus mycelium, then a narrow zone of water-soaked rind, the advancing edge of which is indicated by the dark line drawn on the fruit. B, green mold; aside from the difference in color, this being olive green instead of blue, this usually has a broader band of white mycelium, and a much broader band of water-soaked rind surrounding the mold. The blue mold, known also as blue contact mold, has a greater tendency to spread from fruit to fruit in the container. THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS i r n vluviciilfir/iflf-RV 1 - ' A i C a» Figure 4. Stem-end rot (Diplodia, natwleazsis) in Meyer lemons, howing relative proportions of sound and decayed fruits 10 days to " weeks after harvest in non-treated and treated lots of fruit. A, non- _‘_eated, 50 percent decay (right). B, illustrating a typical result from tyne of the recommended treatments, with only 5 percent decay. Fre- ently much lower percentages than this are attained. penetrate into the fruit tissues through the stem or through i; rindin the vicinity of the stem, thereby initiating the rapidly ‘eloping fruit decay. Winston (21) has dealt comprehensively jh the factors influencing fruit decay. Pruning off all dead wood the orchard reduces the sources of infection and the problem of patrol (23). Spraying the trees with a fungicide likewise reduces amount of potential infective material and thereby reduces the 'dence of decay (23). Pulling the fruit, instead of clipping it, id (23, 24) to reduce the amount of stem-end rot, but possibly 3' crease the blue and green molds (Io) because of breaks in the Dis-buttoning (removing the stem base after harvest) also puces decay (II, 22, 24) but thus far no practicable meanshave developed for doing this uniformly and economically in time }be of value. The ethylene gas degreening process causes the of buttons, but by the time this processing is completed (h infection has already occurred. As is well known, exposure in coloring room predisposes the fruits to stem-end rot, since it 7 8 BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION acts as a favorable incubationchamber for the fungi causing decay; ethylene gas even appears to stimulate the germination of Diplodia spores (2, 3). Extensive experimental work for at least 30 years has been done on the treatment of citrus fruits at the packing house for prevention of decay. Borax was found as early as I923 (I, 8) to be not only an effective fruit wash but also to have disinfectant qualities that resulted in reduction in stem-end rots and blue and green mold rots. For greatest effectiveness it had to be used in a warm, saturated solution (about 110° which permitted a higher concentration than is possible in a cold solution. Sodium metaborate (Metbor) was found to be almost as effective in cold water at a 4% or 5% con- centration (20). Brooks (2, 3) and Miller at al. (I2) give the results of extensive experimental work with sodium ortho-phenylphenate (Dowicide A) concluding that 1.2% is the most effective concentration, that the fruit must be rinsed after treatment to avoid chemical injury, and that stem-end decay control was probably somewhat better than with borax. Brooks (2) reports that including 1.2% Dowicide A in the water phase of a water-wax emulsion at 100° F. caused no injury and gave good control. Childs and Siegler (4, 5, 6) also gave a concise but comprehensive review of the facts known about citrus fruit decays, and detailed accounts of experimental work with the organic chemicals thiourea, thioacetamide, 2-aminothiazone and quinosol (8 hydroxyquinoline sulfate). The first two at 5% aqueous solution and quinosol at 8% reduced decay from 40% to 2% or less. Combinations of these treatments with a waxing process were de- A veloped and gave satisfactory results. The practicability of com- mercial treatments with any of these newer-chemicals remains to i be solved. Work with diphenyl (Io, I3, I4, I5, I6, I9) has indicated that this material used by special methods may fill a place in the handling of citrus fruits. Fruit wrapping tissues and box liners im- pregnated with this chemical reduce decay to a marked degree. They are already in extensive use in some fruit packing houses. In a- separate paper (I7) the authors reported remarkably good results in tests with nitrogen trichloride, and with various chemical treat- ments followed by nitrogen trichloride gas treatments. A new approach to control of decays was recently presented by Siegler and Childs (I8) with water-insoluble chemicals—diphenyl sulfoxide, benzhydrol and phenylurethane in isopropanol. While fairly good control of stem-end rot was obtained, commercial prac- ticability is not yet demonstrated. A THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 9 EXPERIMENTAL METHODS ' The earlier tests were directed largely toward finding a promising eatment that might prove superior to the standard commercial _ eatments, which were far from satisfactory. Attempts were made i.» improve the efliciency of borax and of sodium metaborate by ad- jtions of iodine or other materials. In testing new materials, a i dard treatment such as with borax was frequently included as asis of comparison. 'Each fruit sample for treatment consisted of 200 fruits in most of e tests. To reduce sample variability about IO fruits were taken m each of about 20 field boxes as they were brought in from grove. Applications were made for the stem-end treatment either means of a stamp pad soaked with the chemical in solution, on g 1ch the stem end of the fruit was pressed with a circular motion, ' by a small brush which thoroughly wet the stem or button and i shallow cavity surrounding it. For the complete fruit dip the it, in a mesh bag, was immersed directly into the container of _ution for 2 minutes with constant agitation. Then the fruit was 'ned and poured into crates. If rinsing was required to prevent gmical injury, it was done while the fruit was still wet, usually a hose. The crates of treated fruit were stacked, labeled and cked into the ethylene gas chambers for coloring (degreening). __e period in the coloring room varied from 7 days early in the on when all fruits were completely green, to 2 days or even less en they were already nearly yellow. Degreening was unnecessary some lafe-season tests with well-ripened fruits. it of removal from thecoloring room when the fruit was usually ppped and packed according to standard procedures, and again pier storage at warehouse temperature for about I4 days. Records Qe usually kept separately on duplicate loo-fruit samples. The counts only for the total decay after harvest are reported in bulletin as the average for the duplicate lots. Each table is a densation of the results from several different experiments, as iicated by the dates of treatments. Tests With Soaps and Fruit Cleansers everal fruit cleansing materials were tested for their effectiveness Qpreventing fruit decay. The results are summarized in Table I “ch includes comparable non-treated lots. appears obvious from this table that, for the more important i it rots, the washing compounds alone, in reasonable concentration, {Records of decay development were usually made twice; first at the‘ 10 BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION Table 1. Effects of soaps and fruit washing compounds on decay in Meyer lemons . Duration Concen- Decay, percent Date of days* Material used tration, No. of -— ———— treat- ' percent fruits Stem- ment A B end Other 9/20/38 0 20 Brownsville soap . . . . , . . . . . . . . . . . 1 100 64. 0 . . . . . . . . 12/31/42 4 9 WCC fruit cleanser . . . . . . . . . . . . 1 100 19 8 l/14/43 0 l3 WCC sulfamatachloride . . . . . . . . . 0.25 100 19 15 1/14/43 0 13 WCC sulfamatachloride plus fruit cleanser . . . . . . . . . . . . . . . . . . . . . 0.25 0 . 1 100 25 l4 9/——/38 5 8 Wyandotte fruit cleanser . . . . . . . 2T 25 4 . . . . . . . . 9/20/38 0 20 Wyandotte fruit cleanser . . . . . . . 1 100 60 . . . . . . . . 9/20/38 0 20 Zelco fruit cleanser . . . . . . . . . . . . 0. 4 100 67 . . . . . . . . 9/20/38 0 20 Zellner fruit cleanser. . .. . . . . . . . 0.133 100 83 . . . . . . .. 9/20/38 0 20 Zellner fruit cleanser . . . . . . . . . . . 0.25 100 60 . . . . . . . . Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 31.0 15 *A—time in coloring room; B—-time held at room temperature. TChemical injury and wilting were severe at this concentration. are not effective in preventing decay. It is necessary to use a strong, penetrating disinfectant. This report is not meant, however, to be derogatory to the cleansing agents tested, as such. Stem-end Treatments with Chemicals Some of the early exploratory tests showed that a stem-end treat- ment alone with certain disinfectants gave good control of stem-end decay A number of tests with different chemicals were con- ducted by this method. Only two of the many materials tested showed some promise. Fruit treated with diphenylamine 10% in a mixture of 93% alcohol i and acetone (90 to I0) showed no decay while the corresponding check showed 28%. This material at 1% or less, however, showed no value, with stem-end rot as high as 90%in some of the trials. Tetrachloro-para-benzoquinone (Spergon) saturated in a light min- eral oil to which 10% lanolin had been added to increase its pene- trating power, completely prevented decay; and as saturated in the alcohol-acetone 8o to 2o mixture reduced stem-end rot t0 4% while the check showed 10%. Diphenylamine is an effective disinfectant used in veterinary medicine. Spergon is one of the organic seed disinfectants. ' Many other chemicals were found to be ineffective, or nearly so. The incidence of stem-end rot ranged from 10 to as high as 88%. The ineffective chemicals are listed below as a matter of record. Alcohol, denatured. - Benzoic acid, from 0.1 up to 6% in alcohol (severe chemical injury at 4 and 6%,). ' Borax, 10% in alcohol-glycerin 50-50. Boric acid, 2% in alcohol. THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 11 Hydroxyquinoline, from 0.01 to 0.1% in alcohol, alcohol-glycerin and ' i’ alcohol-acetone, 90- 1 o. Y Iodine, 0.1% in alcohol. Malachite green, 0.1 and 0.05% in water and 50% in alcohol. Mercresin, 0.1% aqueous and 0.02 and 0.04% in 10% acetone. Phenol salicylate, 1 and 4%. Salicylic acid, 0.1, 0.5 and 1% in alcohol and 1% in alcohol-acetone. Undecylic acid, 0.01 and 0.05%. Zinc acetate, 0.5% in 50% alcohol. Octylphenol, 1% in alcohol-acetone. The corresponding checks ranged from 19 t0 86% decay. . The stem-swab method of treating fruit has not been considered eseriously for commercial use 0n citrus fruit as it has on melons. It is, however, a quick means of testing new chemicals that may be ' available only in small quantities. Furthermore, such tests may pro- . vide a lead to materials for treatment by the entire-fruit-dip method. Should the stem-swab treatment prove effective, it may then be fol- . lowed by experimental fruit-dip treatments with the same and closely fallied chemicals. Fruit Dip Treatmentwith Chemicals i‘. __ The preferred method of fruit treatment with a chemical in liquid iform for decay control is the entire-fruit dip. The fruit is brought in from the field in lugs, dumped into the large tank containing the chemical in solution and, after about 2 minutes soaking, is carried gout of the solution by endless chain devices to further processing. iThe coloring (degreening) process when required must be given gprior to the application of any waxing treatment. Consequently, 5 treatment for decay prevention before coloring is an extra process l‘ requiring complete handling of the fruit——dumping, dipping, re- iiboxing, stacking and trucking to the coloring room—before the ‘regular preparation-for-packing procedures are applied. Most of the JJreatments given in this series of experiments from 1938 to 1946 ere by the entire-fruit-dip method. 5 Borax and other materials containing boron, particularly sodium inetaborate (Metbor) have probably been used more extensively in e past several years for the control of various kinds of decay i citrus fruits than any other materials. One or the other was used requently in the series of tests reported in this paper, either as a irect test to determine its value under Lower Rio Grande Valley inditions, or as a_ basis of comparison with other materials. Results tained with borax and sodium metaborate are given in Tables 2 12 BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION 63E; Enmmmfiomw .E5cmu._w E:.~=.8.~=».N 333,2. .w.;.=»~c_:.= Eweiim? . . . . . .. 92 n; .. . . . . .. mi ewa ...... . . . . . . . . . . . . . . ....m:.$Eo_aa:m :23 .o.:3a._om:~o@ E06.- “a 3:25.33 03m . . . . . . .. ... . ...................................M@§QEuflQHuNfl.-Q§ QhnnaflhmwfisQfilsnvQ-nQQ-nnmfi . . . . . . . . . . . M.“ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DuQQw =fi .»m.flOQmv QNGLQ>N QQQ Qu@:h% mfiwQvF mvwnhr»: ©3430? Q w m.®N CON m.Q m.nw AvQN . . . . . . . . . . . . . . . . . . . . . . . ......'H0mO~ Jmmmv JJE N ~§@ fiw m mfixmn .. . 9mm 9m 2: . . . . . V ..Q::E2_E2 :33 8&9? 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Moon» MGHZuOfimQP-OU 29G waanokr wcofiofi E 35cc“. hwuow How v8.3a we wcofifiom E wpnmsbmwnp mmw-fishm mo wfismwm .~.. 289w THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 13 Borax The three cold (room temperature) saturated-borax treatments shown in Table 2 gave very good control of stem-end rot with an r average of only 3.4% decay, while the corresponding checks av- eraged 13.6%. Five treatments at room temperature with additional materials gave 4.8% decay, with the same checks as before. The ; addition of iodine at 0.02 to 0.03% did not give any improvement. Iodine at 0.04% was beneficial in a single test. Borax treatment 80f lemons has a slight corrosive action on the rind of the fruit that _f tends to reduce its brightness. It also hastens the wilting or shrivel- i ing of the fruit. This may be overcome in part by waxing as soon as the fruit is yellow. In a single case in which the borax was used at a high concentration (8% in water heated to 116° to 120° F. in line with some Florida usage), there was 6% decay when the cor- responding check showed 86% decay 21 days after harvest. However, there was extreme wilting in the thin-skinned Meyer lemon used, and the treatment must be considered impracticable forlthat variety i least. In general, the room temperature treatment with a satu— frated solution would appear to justify its recommendation for the control of stem-end rot in late summer and, early fall seasons when - this decay is most active. Borax treatment did not give satisfactory ntrol of green mold in the November tests. sodium metaboratel (Metbor) a l Sodium metaborate, in 14 miscellaneous tests in which the material iiwas used as a basis of comparison with newer materials from Sep- tember 1939 to January 1943, consistently reduced stem-end decay compared with checks, and usually reduced green mold. The _, rest showing was made with 4% solution on a lot of 5o fruits .; September 1939, when 52% stem-end decay developed, as com- red with 86% in the check. Better results in general were obtained 5%. The reduction in 6 treatments with 850 fruits was to an yerage of 6.7% decay as compared with 15.5% in the checks. The dition of iodine at 0.02% (dissolved in a solution of potassium 'ide) appeared to bring about some increased reduction in stem- id rot, thus justifying further experimentation with this material. uctions in green mold were not consistent. In some cases the fcidence of this decay was actually greater in the treated than the non-treated lots. FBI-An effort was made to determine the proper role of sodium metabo- Je for the treatment of citrus fruits in Texas in an extended series ' identical treatments conducted at approximately monthly intervals a July to December 1943. The chemical was used at room tempera- 14 BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION ture, or in some cases, at approximately 85° F., 70° F. and 65° F., in near-saturated solution, mostly 5%. Tests were run in the same series with Vatsol OS added as a wetting agent adapted to use in alkaline solutions, with and without iodine. In this series, 33 lots of 20o fruits each were treated. Since no consistent difference was evident due to either temperature or to month of application, the results are condensed into a single table, Table 3. Results with the Eureka and Meyer varieties are recorded separately. Table 3. Results of sodium metaborate treatments for the control of decay in lemons, July to November 1943 Treated fruit Corresponding checks Variety Treatment Av. decay % and rangei Av. decay % and r No. of ——-——¥—— —-——————— No. of fruits Dipl.* Penic.1' fruits Dipl.* Eureka 5%, 2 min., 85° F . . . . . . .. 1200 22.6 3.9 1000 39.6 (3.5-37.5) (0.5-6.5) (8-68.0) Eureka 5%, + Vatsol, 0.1% . . . . . . 1200 19.0 2. 1000 39.6 (5. 5-35) (0-7. 0) (9-68. 0) Eureka 5% +Vatsol +Iodine 0.02% 1200 14.0 9.1 1200 35.9 (4.5-27) (0-47 l) (8-84) Meyer 5%, 2 min . . . . . . .. . . . . . . . . 1000 5.8 5. 800 40.8 v ’ (0.5-l4.7) (143.5) (l6.0-69.5) Meyer 5% + Vatsol . . . . . . . . . . . .. A 1000 14.8 5. 800 40.8 (3-33) (l-9. 0) (l6. 0459.5) Meyer 5% +Vatsol +Iodine 0.02% 800 8.5 3.8 800 34.5 (2.5-l5.5) ( 5-8) (16-53) *Dipl0dia natalerisis. _ _ TMostly Penicillzum dlgzlatum. ' . IRange is shown in parentheses below the average. Sodium metaborate at 5% did not give satisfactory control of stem-end rot in Eureka lemons. There was 5.8% stem-end decay with the thin-skinned Meyer variety as compared with 40.8% decay in the corresponding checks. There was no substantial benefit from the addition of the wetting agent, Vatsol, or of Vatsol and iodine. Recommendation of the use of 5% Metbor for the control of stem- end decay in Meyer lemons during the summer and fall months would be justified. i Sodium ortho-phenylphenate (Dowicide A) - Preliminary tests conducted in I942 and in January 1943 with sodium ortho-phenylphenate indicated good control of decay in lemons. It was very satisfactory at 1.0% with reduction to I and 2%-stem-end decay, but gave poor control of green mold. In line with results reported elsewhere (3, I2), 1.2% was adopted as the standard concentration for an extended series of tests conducted at approximately monthly intervals beginning in July 1943. It had THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 15 already been shown that this treatment alone resulted in chemical burning of the rind in spots where the chemical dried; and this was further verified by special trials in the extended series. Consequently, it was found necessary to rinse the fruits with tap water after treatment. The addition of formaldehyde to the treatment solution did not eliminate this burning as it did in Florida tests (I2), and rinsing was also necessary to prevent injury. Results of all -tests _ with sodium ortho-phenylphenate are shown in Table 4. Results in the control of stem-end decay with sodium ortho- phenylphenate were extremely erratic, with decay ranging from o to 54%. The treatments did not give satisfactory control with Eureka lemons in a comparable summer and early fall series of tests with immature fruits that required a considerable period in the coloring room. The average of 2 treatments with straight Dowicide A showed 48.2% stem-end rot; 3 treatments in late summer and fall with Vatsol added showed 17.8%, which is a considerable reduction and indicates a value for the added wetting agent. The corresponding 2 checks for each showed 76.0% and 40.7% stem-end decay, re- spectively. The best of these treatments, Dowicide A with Vatsol, did not show sufficient control to be considered practicable. Results were better with the Meyer lemon. There/was an average of 9% stem-end decay in October and November treatments as com- - pared with 57% decay in the checks. With Vatsol added in August, September and October treatments, there was an average of only 1.8% stem-end decay as compared with 31.2% in the checks. Here again the added wetting agent appeared to have real value. Taking the two varieties together, the average stem-end decay in the critical late summer and fall months when losses are nor- mally greatest, was reduced by Dowicide A to an average of 8.2% as compared with 48.7% in the checks. In the absence of a con- sistently better treatment, then, on the basis of this evidence, the use of Dowicide A with a wetting agent added would appear to merit recommendation. The situation is complicated, however, by the need for rinsing, which involves an additional step in the processing. Attention should be called to the single case in November I944 T when Dowicide A was used at 2% concentration on Eureka lemons with reduction of stem-end rot to 0.5% when the check showed 58.5%. There was severe burning with this treatment. Unfortunately, i a corresponding duplication of the treatment with rinsing was not included in the test. 1s BULLETIN 101, TEXAS AGRICULTURAL EXPERIMENT STATION .000... 500-550 0:500 v.50 000.5250 :0 000.... 00550.5 00 5.0.. 55. 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A0005... 00.05.... 5000.. 000.02. ...... 0...... .395. 0000.02. 5.05.5303 0.5. 0.05. 2K 0... 0.0.. 2K . . . . . . .....02.... .... 00.. $00K. 55.1.5.5... + 00K. 5.5 ... .... v1.5 0.55 0.0.. 3K 2.. 0.0K 2K . . . . . . . . . . . . . .505 00.. £00K. ......05..0..5 + $25 w ... 0 $.25 0.5. 0.... 2K 2K 255 2K . . . . . . . . . . . . . . . . . . ....02... J5 00.. :55 K £025 m ... 0 0355 0 0 00 2K 0 0.0 2K .......§....S.....5..P.5+ 002K m. ... 0 .3155 2.. 0.2. 2K 0.0 2K 2K . . . . . . . . . . . . . . . . . . .5002... .... O00 :55 K £02. E K5 K 0155 0K 200 2K 0.. 2K0 2K . . . . . . . . . . . . . . . . . .2002... r... O00 .....5 K £02. 5.. K. 0 05.25 0.0 0 .5. 2K 0.0 2.5 2K . . . . . . . . . . ... . . . . . .562... .... OE. ...-...: K e025 5>. K5 ... 0.105 0 2.... 2K 0... 05.0 2K . . . . . . . . . ... . . . . . . 3.002.... .... 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K5 01.. -|--.. a .... . - ¢ . . . .- c‘? . . ‘ » . - . - - . - - - . - - . . - - . - - . -..-..--UQW:T.—Q&N.F 2 a ...... . . . . - ... . . . . . . .. @.N ...... . . . . . . . . . . . . . . . . ...@mw@h@ QvnMHQuQW-hmk ngAw-M S Aw m . . . . - . - - . - - - . - - - . - - - - - - . . - . - - . - - 2 a n - - ---¢ . - - - ...: a.“ Q - - - . - . - - . . - - - . - . . . . - . -..-..-.%‘o@:1h€°:nm$°-? S a Q @ . . . . . . . . . . . . . . . . . . . . . . . . . . . ..%@QW:@B 6°: 0&@.@ S 40w W 0.50.. 0.50.. .3000 5.0.0.5. 0...... .2535 5.0.0.55 0...... villi! .... dz i: [ill ... .075 ...... .050. 52.. .00. .... 5550000.. £000G 5.500000 $30G 0.5032200 5.550 550.505.500.500 0. 5500M 50-00 050G 50> 00-00550 95.100.500.000 0.55.... 00500.5. .0...§0..0-0... 0.0.8.00 0.. 50.5.5 0.50.50.00.50. .0..0..50. .5. 0505.00 >003. 50w 3.. 0.20.325 000c0s..§>..0s.5-05.0.50 0555.00 m0 0.50.0030 .5. 05.005005... 0.0-0.050 we 00.550005 .5... 030E ywwfimvvy rwjgwqrv m. THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 17 N0 tests were conducted with sodium ortho-phenylphenate 1.2% in the water phase of a water-wax emulsion at 100° F., which has been reported by Brooks (2) and more recently by Winston (cor- respondence) as giving good control without the hazard of chemical injury to fruit. It would seem well established that this method for treatment with Dowicide A is safe and reliable. It should not be used before coloring, however, as the wax coating greatly retards yellow- ing in the coloring room. Ineffective chemicals Among the many chemicals tried by the fruit-dip method, several did not show promise at the concentrations tested. The treatments showing more than 10% decay are as follows: G-4-40, monosodium salt of 5-chloro-2-hydroxyphenyl methane, 1 % aqueous. G-11, bis-(3,5,6-trichloro-2-hydroxyphenyl) methane, 0.5 and 0.2%. Copper sulphate,, 0.125% (resulted in apparent stimulation of stem-end decay). Dihydroxydiphenyldimethyl methane, 1.2%. Diphenylamine, saturated aqueous. Dithane, liquid, y; and 1%. F ermate (ferric dimethyl dithiocarbamate), 0.125%. Hyamine 1622, 25% aqueous, (di-isobutylphenoxyethoxyethyl dimethyl benzyl ammonium chloride), at 0.2, 0.4 and 1%. 8-Hydroxquinoline, 0.0 1 % . 8-Hydroxy quinoline sulphate, at 0.5, 0.75 and 1%. Iodine in potassium iodide sol., 0.02 to 0.04%, each in 3 times the con- centration of potassium iodide KI). _ Roccal (brand of Benzalkonium chloride, Winthrop Chemical Co., Inc.), 0.2 to 1 %. Salicylic acid, 0.25%, and same in alcohol 0.2%. Santobrite (sodium pentachlorophenate), 1%. 4 and 9.5% decay, with checks over 4o 0,6. a Sodium dimethyldithiocarbamate, 0.2 % . Sodium hypochlorite, 0.7 5 to 2% as Cl (chlorine). Isothan, 0.2%. Diphenyl Tissue Wraps-as Supplemental Treatment A series of tests were conducted in the summer, fall and winter of I943 and in the fall of 1944 to test the efliciency of diphenyl— impregnated tissue fruit wraps for stem-end rot control. They were used both with and without initial fruit-dip treatments. The benefits obtained were substantial in the summer and fall tests when stem- end rot is normally high. In a series of 7 tests with Metbor on both Eureka and Meyer lemons, there was an average of 11.7% stem-end decay with plain wraps and only 2.8% with diphenyl wraps. In tests with Dowicide A treatments there were averages for Eureka and Meyer together of 7.46% stem-end decay in plain and 4.0% in diphenyl wraps. In the check lots, without prior treatment, there 18 BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION 0030- =30 0E3 0:0 980E m“ a0»? 153:5“. 0-: Gm >000“. 1:04:03 E0 000033; E0500 0n 50E 09-3-0220 0E3 E: 10.20000 E0000 EEEZEUmGQ-Em 0: 005m NwwQGMEuQQOU-Z 2 030.» 0.: ANNE 00$ M5002 0E: E E050 0E 0:0 DEEP:- NE 09-3-0120 E3 05mm E 0N5: E0000: 0E0: 0.5m: 0>EE0u0EE 0E3 0:55P Exit-Noe .E0N0E.. EEEEEEENEESNEMEE ENZNEEENENEZEEN 0.0: P5000 E002 022E 0: < .._0.E0E NE E ENEEEZEEH m2 m?“ NEE. NNN NE N.EN 3N N.E N.EE N3 . . . . . . . . . . . . . . . . QNNNE NNNEN £82. NNNSZ. 2:. N55 130,-. h.mfi fi.N m-E.b N.N QQQN . . . . . . . . . . . . . . . . . Ihfiknvz UQGQIU “E8005 Qwdumzrfl mun-d waif-M fiNeQEF v.00 Qua ENG Nina an: u.» ENE NmQE . . . . . . . . . . . . . . . . . ..00_0.=EH E-uo-Eu £0005 0mNE0>0 0:0 waif-w 130E NNN NNE. N.N N.E EKE. N.N N.N ES. . . . . . . . . . . . . . . . . tSEPEEEH E635. £0000 322E 2:. 5N: ENENE. N.NE| E. N NEE NNE. NNN N.NE NE. NNN ........3EE. N5 ENNEQ H E N ESE NNN E.NE N.N NNN NNNE N.N N.EN NNNE 2.2.5. _N22NE.E =< EE E N ESE N.E ENNNN: 0E» N.E NNN NEE N.N NNN ........E5. N5 E850 NE NE N NENE 0.: N E.E. NE EN NEE NE Eém . . .25. _N22NE.E =< m NE N mENE E....N NNN N.N NNN NNN NE N.N NNN ........E5. N5 ENNEQ E E N NENE NNE. N.NN N.N ENE 3N N.N N.E NNN . . . .25. _NE.E2NE.E =< E E N nEloE EN NNN N NNN NNN N N.N NNN E5. N5 N820 w E N NENE 0E7! ....NN N.N EiNN 3N N.N N.N NNN . . . .25. EucEuEw-EEC =< H E N NENE NNE N.EN NE NNE NNN N N.N NNN IIIIQEEE. N5 N820 E E N NEN N 0.0m E.E N.N 3N E.E N.N 3N .2125. ENNENENNNE =< E E N NEN 3E1 NNN N.N NNN 3N N.E N.N 3N ........EEO N5 .125 m E N NEN NNEI N.N» N.N E.NE 3N N.N N.N 3N IE5. 1.2238 =< EE E N NEN +1 NINE. N NNN 3N NE N.NN 3N ......25. N5 .350 E E N NEN 53 NNN N.E N.N 3N E0 N.N 3N . ..N.5. 122N525: =< E E N NEN 3N! NNN N.N N.NN 3N NE 0E4" 3N ... . . . .25. N5 .320 EE E N NEN 3E| N.N E.E N.N 3N N.N N.N 3N . . . .25. ENNENENNNE =< EE E N NEN IIIIIIIIIII -n-N~|--||-¢|uu =1... . . N - - -.u - - - | . - - - - - . . .- N.-.NN.%QI”°=Q a NEN EtNN NE. E4 3N N E N.N 3N . . . .95. ENENEMEEEC =< H EE NE NE... 6500M 533G 4200M 525G mini 6200M 633G waif-u .050» 500.. 500E 3-00 EN NZ lllall EN NZ 02.22. i. EN .NNN.:$ 59...; NZ 38 EN 30010:. 5:09-05 $80G 25300 $03G 0E E010 wEEQEudQ-EH. 0E 30G 0E 03E x0001 l 10> 0.3% 5.2.3 Ewoa. E0 00.50000» N553 52m N523 EESEEEG EEE00E0G NEENEEENE E MNNNEN mo ENEEEENN 0%. Mom N933 ENE 2.8 E5055. 00025.05 NEENNEENEEEEENO .m 03mm. 1;‘ - 1-'.~»--;-».-.-1~¢ww-3nr.:v.-w:~1~ < w" 1w “w r Pr" “ 1- ' THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 19 was an average of 31.9% decay in plain and 11.0% in diphenyl wraps. The results with all fungicidal dips, with and without di- phenyl wraps, are recorded in Table 5. The results shown in the columns of averages, Table 5, indicate substantial benefit derived from the use of diphenyl wraps. With but one exception, greater reduction of stem-end rot from the use of diphenyl wrap is indicated in the last column. In that exceptional case, a winter treatment with no prior fungicidal dip, the incidence of green mold decay was very high in the plain wraps, 71%, and probably destroyed some fruits that would have developed Diplodia rot. The average of 6 treatments of Eureka lemons with “all fungi- cides” showed 14.3% stem-end decay in plain wraps and 7.4% in diphenyl wraps; “no prior dip” showed reduction of the decay from 25.7% in plain wraps to 17.4% in diphenyl. The average of 3 treatments of Meyer lemons with all fungicides showed 7.5% stem- end decay in plain wraps and 2.4% in diphenyl; the corresponding check lots (no prior dip) showed 31.2% in plain and 11.8% in diphenyl wraps. While reduction of stem-end decay has been shown from the use of diphenyl wraps alone, it has not been sufficient in heavy in- cidence of decay to be considered as giving satisfactory commercial control. When, however, the diphenyl wrap followed a good dip treatment for control of decay, its supplementary effectiveness was usually sufficient for satisfactory commercial control. In all the summer and fall tests reported in this bulletin, the incidence of green mold decay was so low as to be considered neg- ligible. Results of winter tests in which green mold decay was more prominent are included in the section devoted primarily to it. The Control of Penicillium (Green Mold) Decay Up to this point, citrus decay of the stem-end rot type, caused in the Lower Rio Grande Valley chiefly by Diplodia natalensis, has been the main topic. While this is usually the main cause of loss of citrus fruits in transit and storage, there are frequently heavy losses due to the green mold, and to a less extent to the blue mold. These molds are usually not much of a factor in the summer and early fall. There is a sudden drop in the incidence of stem-end rot and a rise in green mold decay beginning in November or December. The drop in temperature in the winter months is unfavorable for the development of Diplodia but is favorable for Penicillium. The . increased maturity of the fruits makes them more tender and, there- fore, more susceptible to bruises and rind injuries. Most of the 20 BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION tabulations in this paper give results in the control of green mold. In practically all of them, the only check lots that show green mold decay of 10% or greater are in December and January, and oc- casionally in November and February. There are indications in some of the tables that certain chemicals are of high value for controlling green mold. Results occasionally were inconsistent. In one November test with 4% borax (Table 2) in which there was 19.5% green mold decay in the check, there was a considerably higher percentage in the treated lot. Metbor at in a December test (Table 3), showed only 3% green mold, and Metbor with iodine added showed 2%, when the check gave 1o. 5% green mold. Green mold rot was 6% in another treatment in the same test when the fruit was rinsed afterward. In a January test. next in the series With Metbor, the treatment showed 13% decay. with 19. 5% in the check; and in an identical treatment followed by a standard waxing, the decay was 26% which was higher than the check. In one other winter test, with the check showing 47% green mold decay, the addition of the wetting agent Vatsol did not add to its effectiveness. In general, there was never any indication that the addition of Vatsol or Vatsol and iodine at 0.02% in potassium iodide solution) contributed to the effectiveness of the Metbor treat- ment. In a December test with 1% Dowicide A. there was 5% green mold (Table 4), with the check showing 10.5% decay; but when the treatment was followed by rinsing in tap water to prevent chem- ical injury there was 25% green mold decay, as compared with 19.5% in the checks. In a January treatment with 1.2% Dowicide solution, rinsed, there was 24% decay while the check showed 19.5%. In a November 1944 treatment of the same kind, there was 2.0% decay, with 11.5% in the check. These results in general indicate borax, sodium metaborate and sodium ortho-phenylphenate when used alone are rather unreliable for the control of green mold. Several experiments were conducted in an attempt to reduce Penicillium decay to a point below that obtained with the standard chemical treatments. Diphenyl-impregnated tissue wraps for green mold control Most of the tests with diphenyl wraps were made in the summer and fall when green mold was not a serious factor. In the series of 7 tests including both Eureka and Meyer lemons, there was an average of 2.5% green mold in the plain wrap as compared with 1.5% in the diphenyl wrap. Referring to Table 5, recording “all fungicidal-dips” as against no dip, in the December 1943 test which THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 21 alone shows severe green mold decay, there was a reduction from 44.1% to 11.2% due to the use of diphenyl wrap. There was 52.7% green mold in plain wraps and 10.7% in diphenyl following a stand- ard Metbor treatment. ‘ The value of diphenyl was further demonstrated in tests with another method of application in 1946. Diphenyl was applied in the form of impregnated pads each consisting of 8 sheets of wrapping , tissue 12 by 24 inches in dimensions, which were placed in the bottoms, between each packed layer and on the tops of the packed crates. The fruit was not especially treated for control of decay but went through the regular commercial washing process followed by drying and waxing, and was packed non-wrapped. The tem- perature range during the 2-week holding period was mostly 50° to 60° F. With Temple oranges there was only a slight reduction in green mold, 7.0% in the check and 5.5% in the diphenyl-pad l» crate. The corresponding reduction was from 17.6% to 7.9% with i’ pineapple oranges, which had received the color-added processing. Z Diphenyl alone appears beneficial in that it greatly reduces the ' incidence of green mold; but its greatest practical value is as a _ supplement to a beneficial fruit-dip treatment. Here a consistent f additional reduction of green mold as well as of stem-end rot occurs. Fumigation with Nitrogen Trichloride (Decco)1 Considerable experimental work was done during the fall and winter of 1946 with nitrogen trichloride gas for the control of decay _ in lemons. The detailed results of this work are reported in a sep- arate paper (17). The gas, in concentrations of from .007 to .04 parts per million, was used in the coloring room for periods of 2 to 1 6 hours per treatment. The first fumigation was given as soon as pos- , sible after the fruit'was placed in the coloring room. Subsequent 1 treatments were spaced 24 to 48 hours apart depending on the length of the coloring period. While the nitrogen trichloride treatment Talone did not always give adequate control of stem-end rot, it did reduce the incidence of this decay considerably. When used fol- lilowing chemical dips, it added to the degree of control obtained with 1the dip alone. In cases where such dips as sodium metaborate and l-LQ-quaternary ammonium compounds alone were not sufficient, the {addition of nitrogen trichloride treatments in the coloring room ibrought about satisfactory control. The combination of chemical ‘dip immediately after harvest followed by nitrogen trichloride treat- ' 1 5 1The Decco process and equipment for its application are produced by gWallace & Tiernan Sales Corp., 3630 East Colorado St., East Pasadena, géCalifornia. 22 BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION merit in the coloring room appears t0 be a practical method of ma- terially reducing the hazard from stem-end rot and green-mold rot in lemons. RECOMMENDATIONS Even though the type of decay in lemons varies with the season, Diplodia stem-end rot being the principal factor in the summer and fall,’ and blue and green molds in winter, the treatments recom- mended are the same throughout the harvest season, from June to January and February harvests. When a prolonged coloring (de- greening) period is required for early-harvested fruits any treatment involving the use of wax must be deferred until after the fruits are yellow. Late lemons that are already well colored can be waxed im- mediately after treatment. The successive steps for all lemons are as follows: I. Use extreme care to avoid bruising or breaking the rinds at all stages of handling, including picking, placing in lug boxes, hauling to the packing shed, dumping, dipping, re-boxing, stacking in the coloring rooms, and finally the various handling procedures up to packing and shipping. Initial dipping treatments should be given as soon as possible after harvesting and hauling from the field to the packing house. ‘ l ’ 2. The freshly harvested fruits are dumped from lug boxes into the dipping tanks where they receive a I to 2-minute soak in one of the following solutions, at room temperature: a. Sodium metaborate (Metbor), 4.5 to 5 percent. b. Sodium ortho-phenylphenate (Dowicide A), 1.2 percent, with wetting agent added, Vatsol OS at 0.1%. The fruits must be rinsed before stacking in the coloring room in order to avoid the slight chemical burning that occurs otherwise. 3. The next step may be a choice between 3 entirely different treatments. a. While in the coloring room the lemons may be subjected to nitrogen trichloride gas (Decco Process) by injecting a minute quantity of the gas, 0.03 parts per million, into the room from one to three times, for about 4 hours each treatment. b. After coloring, repeat treatment No. 2 above, then follow immediately with a wax-emulsion treatment by one of the var- ious means available, with Dowicide A at 1.2 percent in the water phase of the emulsion. c. After treatment No. 2, a or é, and after the fruits are well colored, follow with aregular waxing treatment, then wrap the fruits individually with diphenyl wraps. i“ THE CONTROL OF TRANSIT AND STORAGE DECAYS IN TEXAS LEMONS 23 n the experiments reported in this bulletin the _recommended tments have consistently reduced decay from percentages rang- from IO to 85 percent down to from o to 5 percent. Where chemical-dip treatment alone has not been satisfactory, as in seasons of high incidence of decay, the supplementary treat- ts suggested have almost invariably brought control of decay a satisfactory range. The supplementary treatments are especial- iss-‘recommended fortEureka lemons with which the chemical-dip fitment alone has frequently failed to give satisfactory control. precaution. It is never wise to wash: fruits unless a disinfectant iintained in the wash water. To do so is very apt to increase the nt of decay, particularly green mold, over what would occur in rocessed fruits. i 24 IO. II. I2. 13. 14. I5. 16. 17. 18. 19. 20. 2I. 22. 23. 24. BULLETIN 701, TEXAS AGRICULTURAL EXPERIMENT STATION LITERATURE CITED Barger, William R. and Lon A. Hawkins. Borax as a disinfectant for citrus fruits. jour. Agr. Res. 3o: 189-192. 1925. Brooks, Charles. Stem-end rot of oranges and factors affecting its con- trol. jour. Agr. Res. 68: 363-381. 1944. Brooks, Charles. Prevention of stem-end rot. The Citrus Industry 24 (1): 3,6-8, january, 1943, and (2): 3,6-8, February, 1943. Childs, j. F. L. and E. A. Siegler. Experimental control of orange decays. Phytopath. 34: 983-985. 1944. Childs, j. F. L. and E. A. Siegler. Compounds for control of orange decays. Science 102: 68. 1945. Childs, j. F. L. and E. A. Siegler. Controlling orange decay. Ind. Eng. Chem. 38: 82. 1946. Fawcett, Howard S. Citrus diseases and their control. McGraw-Hill Book Company, Inc. New York and London. 1936. Fulton, H. R. and j. j. Bowman. Preliminary results with the borax treatment of citrus fruits for the prevention of blue mold rot. jour. Agr. Res. 28: 961-968. 1924. Godfrey, G. H. Stem-end rot control experiments. Tex. Agr. Exper. Sta. Ann. Rpt. 51: 235. 1938. a Hopkins, E. F. and K. W. Loucks. The use of diphenyl in the control of stem-end rot and mold in citrus fruits. The Citruslndustry 28 (Io): 5-9. Oct. 1947. Meckstroth, G. R. Pulling versus clipping of Florida oranges. Citrus Industry 25 (11): 9,12,18. 1944. . Miller, Erston V., j. R. Winston and G. A. Meckstroth. Studies on the use of formaldehyde and sodium ortho-phenylphenate in the control of decay in citrus fruits. Proc.,‘ Florida State Hort. Soc. 57: 144. 1944; also Citrus Ind. 25 (10): $15. 1944. Parkas, A. The practical application of impregnated wrappers against fungal decay of citrus fruit. Hadar 11 (9): 261-267. 1938. Parkas, A. Control of wastage of citrus fruit by impregnating wrappers on a commercial scale. Hadar 12: 227-230. 1939. _ Parkas, A. and j. Aman. The action of diphenyl on Penicillium and Diplodia moulds. Palestine jour. Bot., 2: 38-45. 1940. Ramsey, G. B., M. A. Smith and B. C. Heiberg. Fungistatic action of diphenyl on citrus fruit pathogens. Bot. Gaz. 106: 74-83. 1944. Ryall, A. L. and G. H. Godfrey. The use of nitrogen trichloride gas in reducing decay in citrus. Phytopath. In press. Siegler, E. A. and j. F. L. Childs. Isopropanol-soluble compounds in controlling stem-end decay of oranges. Phytopath. 37: 399-402. 1947. Tompkins, R. G. Report of the food investigational board for the year 1935. Dept. Sci. Indus. Res., London, pp. _129. 1935. Winston, j. R. Reducing decay in citrus fruits with borax. U. S. Dept. Agr. Tech. Bull. 488. 32 pp. 1935. Winston, j. R. Some factors influencing decay in Florida citrus fruits. Fla. State Hort. Soc. Proc. 46: 82-84. 1933. Winston, j. R. A method of harvesting grapefruit to retard stem-end rot. U. S. Dept. Agr. Cir. 396. 8 pp. 1936. Winston, j. R., Harry R. Fulton and john j. Bowman. Commercial control of citrus stem-end rot. U. S. Dept. Agr. Cir. 293, 1o pp. 1923. Winston, j. R. and G. R. Meckstroth. Decay control in Florida lemons. Citr. Ind. 25 (2): 6, 7, 1o, 18, 19, 22. Feb. 1944.