ALBERT R. MANN 
 LIBRARY 
 
 New York State Colleges 
 
 OF 
 
 Agriculture and Home Economics 
 
 AT 
 
 Cornell University 
 
DEPARTMENT OE AGRICULTURE, VICJORIA. 
 
 FUNGUS DISEASES 
 
 CABBAGE AND CAULFLOWER IN 
 YICTOEIA, AND THEIE TEEATMEWT, 
 
 WITH SIX COLOUEED PLATES .AND FIGURES. 
 
 D. Mc ALPINE, 
 
 GOVERNMENT VEGETABLE PATHOLOGIST. 
 
 JANUARY, 190i; 
 
 ROBT. S. BRAIN, GOVERNMENT. PKINTEE, MELBOURNE. 
 11179. 
 
The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924002904864 
 
n)EPAKTMENT OF 
 
 FUNGUS DISEASES 
 
 CABBAGE Am CAULIFLOWEB IN 
 TICTOEIA, km THEIR TBEATME^^T, 
 
 WITH SIX COLOURED PLATES AND FIGURES. 
 
 2D. MoALFINE, 
 
 -GOVERNMENT VEGETABLE PATHOLOGIST. 
 
 JANUARY, 1901. 
 
 ROBT. S. BKAIN GOVERNMENT PRINTER, MELBOtJRNE. 
 
 ■;in79. 
 
ERRATUM. 
 
 Explanation of Plates, page 35. 
 Plate VIII., fig. 7, for ( x 1,000) read ( x 600). 
 
CONTENTS. 
 
 Paiye 
 
 Introduction ... ... ... ... ... ... 5 
 
 Manuring ... ... ... ... ... . g 
 
 Varieties ... ... ... ... ... .. 7 
 
 Selection of Seed ... ... ... ... g 
 
 General Treatment ... ... ... ... ... g 
 
 I. Black Leg or Foot-rot — 
 
 Iniroductory ... ... ... ... ... ., ij 
 
 Distribution .. ... ... ... ... ... 12 
 
 Host-plants and parts affected ... ... ... ... 12 
 
 Symptoms ... ... ... ... ... ... 12 
 
 Effects ... ... ... ... ... ... 12 
 
 Cause ... ... ... ... ... ... ... 12 
 
 Treatment ... ... ... ., ... ... 12 
 
 II. Club-root or Botch — 
 
 Introductory ... ... ... ... ... ... 15 
 
 Host-plants and parts attacked ... ... ... ... I5 
 
 Symptoms ... ... ... ... ... ... 15 
 
 Conditions favouring the disease ... ... ... ... 16 
 
 Cause ... ... ... ... ... ... ... 17 
 
 Life-history of Club Fungus ... ... ... ... ig 
 
 Infection Experiments ... ... ... ... ... 19 
 
 Preventive Measures ... ... ... ... ... 19 
 
 an. White Rust- 
 Introductory ... ... ... ... ... ... 23 
 
 Host-plants and parts attacked ... ... ... ... 23 
 
 Distribution ... ... ... ... ... ... 23 
 
 Symptoms ... ■-. ... ... ... ... 23 
 
 Effects ... ... ... ... 24 
 
 Cause... ... ... ... ... ... ... 24 
 
 Treatment ... ... ... ... ... ... 25 
 
 IV. Ring-spot of Leaf — 
 
 Introductory ... ... ... • ... ... ... 27 
 
 Parts attacked ... ... ... ... ... ... 27 
 
 Distribution ... ... ... ... ... ... 27 
 
 Symptoms ... ... •-■ ... ... ... 27 
 
 Effects ... ... ... ... 27 
 
 Cause... ... ... ... •■. ... ... 27 
 
 Treatment ... ... ... ... ... ... 28 
 
 V. Putrefactive Mildew^ 
 
 Introductory ... ... ■•. ■■■ ■•■ ... 33 
 
 Plants and parts attacked ... ... ... .... 33 
 
 Distribution ... ... .. ... ... ... 33 
 
 SvmBtoms ... ... ... ... ... ... 33 
 
 Cause... ... ... ... ... "• ••• 34 
 
 Treatment " ... ... ... ... ... ... 34 
 
 Explanation of Plates ... ... ,-. . ... 35 
 
 Appendix — Report on Garbage Destructor, by J. Monash, M.C.B. 36 
 
INTRODUCTION. 
 
 Considerable loss to market gardeners in the neighbour- 
 hood of Melbourne has been caused for a number of years 
 past by various diseases in the cabbage and cauliflower 
 crops. I refer more particularly to the Brighton district, 
 where this industry has attained large proportions and 
 gives employment to a great number 'of people, and since 
 there is a considerable export trade in these products, it is de- 
 sirable that everything which interferes with its proper de- 
 velopment should be removed. I have not returns for these 
 particular crops, but I find, according to the records of the 
 Department of Trade and Customs, that the export of fresh 
 vegetables in 1899 was valued at £4,740. The diseases of 
 the cabbage and cauliflower are generally considered to be 
 due to insects, and, no doubt, they do a deal of damage in 
 favorable seasons, but I have also found that quite a number 
 of serious diseases are caused by fungi, and the following 
 Report deals with such diseases. Only the principal diseases 
 are dealt with, and they are as follows ; — 
 
 1. Black Leg or Foot-rot. 
 
 2. Club-root or Botch. 
 
 3. White Rust. 
 
 4. Ring-spot of Leaf. 
 
 o. Putrefactive Mildew. 
 
 The "Black Leg" is perhaps the most serious trouble with 
 which the grower has to contend, and the neglect of it for a 
 number of years past, combined with the encouragement 
 given to its spread by ignorantly ploughing in the diseased 
 portions, has given it a strong foothold in the district. 
 The Club-root is also very prevalent in some seasons and the 
 too common practice of allowing the diseased plants to rot 
 in the ground or to be thrown on the manure heap, cannot 
 be too strongly condemned. 
 
 Of course, the grower is more immediately concerned in 
 the methods of treatment — how to get rid of or how to 
 prevent the disease — but he ought to know that a rational 
 
system of treatment cannot be devised until a thorough, 
 knowledge of the nature and life-history of the fmigus 
 concerned has been acquired. 
 
 In short, the disease has to be diagnosed before remedial 
 or preventive measures can be intelligently applied. And 
 just as the laws of health have to be observed among our- 
 selves in order that the body may be fully and properly 
 developed, so there is a plant hygiene requiring that it be 
 surrounded with healthy conditions and provided with suit- 
 able food, if it is to thrive properly. Hence attention has 
 to be paid to the cultivation of the soil, to drainage, to 
 manuring, and to the selection of varieties suited to the 
 district, as well as direct treatment for the specific disease. 
 
 The plant must have all its needs supplied if it is to grow 
 up vigorous and healthy, and the frequent stirring of the 
 soil is necessary in order that the roots may be well aerated, 
 that they may act freely in absorbing nourishment, and that 
 the soil constituents may be rendered readily available. 
 Good cultivation, in short, will produce proper aeration of 
 the soil, will conserve the moisture by forming a surface 
 mulch to prevent rapid evaporation, and will destroy the 
 weeds, wliich not only rob the soil of valuable plant-food, 
 but are in many cases harboring disease. Cold, wet, sour 
 land is unfavorable for growth, and drainage is necessary 
 in such cases. It also increases the effect of manures, or, as 
 the growers say, manures act better with drainage, because 
 they are more thoroughly dissolved and reach the feeding 
 roots of the plant. 
 
 Manuring. — There are few soils, if any, sufficiently fertile 
 to grow perfect crops of cabbage and cauliflower, and when 
 not properly fertilized they give evidence of it in small 
 heads and late ripening, so that a good marketable com- 
 modity is not produced. In order to obtain profitable crops, 
 the land must be fertilized systematically, and the question 
 arises — What is the most effective and most economical 
 manure to apply ? Stable manure is considered the best for 
 this crop, but commercial fertilizers may also be used. 
 Experiments would require to be carried out in order to 
 determine the most economical manure to employ in a given 
 district, but there is already a large body of information to 
 draw upon to guide us. Mr. Pearson, the Government 
 Agricultural Chemist, informs me that he has recommended 
 
lime to be applied to the soil just before planting with good 
 results, and to those asking advice he has always suggested 
 .a mixture per acre of about — 
 
 2 cwt. Sulphate of Ammonia ; 
 2 „ Nitrate of Soda ; 
 3 or 4 „ good ordinary Superphosphate ; 
 1 „ Potash Chloride. 
 
 'This to be applied to the la,nd before planting, and occa- 
 sionally watering afterwards with a solution of about 3 or 4 
 ounces nitrate of soda to 10 gallons of water. 
 
 The cauliflower is even more exacting than the cabbage 
 in this respect, and requires exceedingly fertile soil. In the 
 "New Horticulture," by Mr. StringJFellow, the following 
 advice is given: — "The ground can scarcely be made too 
 rich for this crop, and should always contain a full supply 
 of potash and salt. The latter is a special addition for 
 "both cauliflower and cabbage, and should never be omitted, 
 for, though it does not seem to stimulate growth at all, it 
 is for certain plants a wonderful tonic, so to speak." To 
 many plants Salt is what might be called an appetizer, en- 
 abling them more readily to absorb and assimilate their food, 
 .and it must not be forgotten that in this instance it is 
 natural. The common cabbage is fouiid in its wild state on 
 the rocks by the sea-shore, and is a coast plant, from which 
 "the cultivated varieties have originated. In the case of the 
 turnip crop a considerable increase was obtained by the 
 addition of 4 cwt. of salt to 30 carts of dung per acre, and for 
 cabbage a manure consisting of 25 to 80 tons of well-made 
 farm-yard manure, with the addition of 2 to 3 cwt. of super- 
 phosphate and 2 to 4 cwt. of common salt, was very beneficial. 
 Deep cultivation and heavy manuring are absolutely essen- 
 tial to success. 
 
 Varieties. — The choice of varieties is very important both 
 irom the point of view of yield and the liability to disease. 
 The mere fact that a Club-proof turnip has been secured 
 'shows that a variety of cabbage or cauliflower might be 
 obtained resistant to the Black Leg, for instance. It has 
 been observed in the Brighton district that some varieties 
 •of the cauliflower are less liable to the disease than others, 
 :and the careful selection of seed from s'uch plants should be 
 jnade. By picking out the first formed seeds and sowing 
 
them alongside those developed later a strain might be- 
 obtained suited to the district and more or less resistant to- 
 Black Leg. 
 
 Selection of Seed. — Experience has proved that the best 
 seed is obtained from cabbages with the finest heads. It 
 has also been found that seed gathered from the central 
 stem produces plants which ripen a fortnight earlier than 
 those from seed of the lateral flowering stems. It has been 
 noted by C. L. Allen that specialists on Long Island,. 
 America, who pay great attention to growing cabbage for- 
 seed, always carefully examine each plant before cutting, 
 and if the seed is of large size it is rejected, because they hold 
 that such seed will make leaves instead of heads. Besides 
 that, these men will not use seed until it is at least three 
 years old, for the same reason. 
 
 General Treatment. — While each particular disease will 
 be fully described, and preventive measures given, still there 
 are several precautions which are generally apj)licable, and 
 which may be noted here. 
 
 1. Clean cultivation is of first importance, and it is 
 particularly necessary that all cruciferqus weeds should be 
 destroyed, since they often harbour the fungus diseases which, 
 readily plass to cultivated plants. 
 
 2. As the refuse from diseased plants contains the germs 
 of many diseases, it should not be added to the manure heap, 
 but destroyed by burning or buried deep in some out of the 
 way corner. 
 
 3. Sincethe fungi recorded here generally confine themselves, 
 to plants of the Crucifer family, and since the soil may become 
 infected by them, a change of crop 'is desirable in order that 
 the fungus may be starved out. The successive growing of 
 cabbages and cauliflowers in the same soil tends to weaken 
 the plant, and predispose it to disease. 
 
 4. As certain varieties are found to be less liable to disease 
 than others, such varieties should be chosen, other things 
 being eq[ual. 
 
 5. Since the fungus generally attacks the young and tender 
 plant in the seed-bed, some fungicide might be added prepa- 
 ratory to sowing, which would not hav§ an injurious effect 
 ,upon the seed. Sulphate of copper and Bordeaux mixture are; 
 both being tried during the present season. 
 
6. Too much attention cannot be paid to the care and. 
 selection of a suitable seed-bed. 
 
 A good seed-bed should always be prepared in fresh groiuid,. 
 and the plants should not be allowed to become crowded, in. 
 order that only well-developed and perfectly healthy plants 
 may be available for transplanting. It is considered good 
 practice to strew the land to be used for a seed-bed with dry 
 brush-wood, and burn it over before ploughing. 
 
 A strict watch should be kept for the slightest trace of 
 disease in the seed-bed, and any such dis.eased plant should 
 be promptly destroyed. 
 
 With reference to » the plates illustrating this work, the 
 figures representing the various diseases have been drawn 
 by Mr. C. 0. Brittlebank, who has, with his usual skill, 
 pourtrayed them in a life-like manner, and the handsome 
 series of photomicrographs reproduced were executed by my 
 assistant, Mr. G. H. Robinson, who has made a specialty of 
 this particular class of microscopic work. 
 
PLATE I. 
 
 Blaok Leg of Cauliflowkb and Cabbage. 
 
 {TPhoma brassiccs.) 
 
 This Cauliflower Stump shows the minute punctiform black 
 peritliecia studding it in immense numbers, and was taken from 
 the ground on 16th August, 1900. 
 
Plate I. 
 
 BLACK LEG 
 <Phoma brassioae, Thuem.J 
 
11 
 
 I. "BLACK LEG" OR " FOOT-EOT " OF 
 CAULIFLOWERS AND CABBAGE. 
 
 {Fhonia brassicce Thuem.) 
 
 This is a disease which is very prevalent in certain districts 
 and causes considerable loss, so much so that some growers 
 regard it as the worst disease with which they have to contend. 
 It was first brought under my notice by Mr. Molineux, secretary 
 to the Agricultural Bureau, Adelaide, who sent specimens of 
 ■diseased cauliflowers with the accompanying note, under date 
 15th October, 1897: — " By present mail I send you some roots 
 ^nd leaves of cauliflowers, grown by W. E. Madden, Auburn, 
 South Australia, and apparently attaelced by a fungus which does 
 not affect cabbage plants grown close by. Twenty -five per cent, 
 ■of the plants died completely, and over 50 per cent, were attacked. 
 Some of the plants produced good heads, but the lower part of 
 "the stems were constricted, shrivelled, lost their bark, and became 
 -cracked and quite dry and brittle. In a few cases the injury ex- 
 tends up the midrib of the lower leaves, causing them to split. 
 In other cases the roots dry and shrivel, and in all cases the cen- 
 tral part of the stem is discoloured." 
 
 In every instance the superficial tissue of the diseased roots 
 and stems showed numerous black punctiform bodies, which did 
 inot usually extend above ground. The fungus evidently caused 
 the roots to rot, and consequently the green parts above ground 
 Buffered more or less according to the period and the virulence of 
 ratiack, and in many cases the plants died completely. 
 
 This cauliflower disease was also met with at Brighton, and 
 Mr. Cronin, inspector under the Vegetation Diseases Act, called 
 :atteation to the serious nature of it in June of this year, stating 
 that fully 90 per cent, of the plants were affected in some in- 
 stances, and estimating the loss in the Brighton district at £5,000, 
 ■one grower alone sustaining a loss of £200, 1 visited this district 
 in August, and found the disease not only in cauliflowers but also 
 in cabbages. This was certainly only found in one garden where 
 the land was well drained, and the cabbage seems hitherto to 
 have largely resisted attack, but as in so many other cases, 
 the fungus extends its ravages to other members of the same 
 ;family when allowed to gain a footing in a district. The smaller 
 losses in cabbage crops hitherto is probably owing to the fact 
 that it is hardier than the cauliflower, is not weakened by flower- 
 ing, nor so liable to injury by frost, and when the main root is 
 attacked it can throw out fresh roots above the point of attack 
 .and thus, partially at least, save the plant, this property not 
 feeing nearly so marked in the cauliflower. 
 
12 
 
 Distribution. — This disease is not con|ined to Australia, but 
 occurs in France and Germany. In France it does considerabl& 
 damage in the west, where cabbages are largely grown for tije- 
 feeding of animals. It probably occurs in other parts of Australia 
 besides Victoria and South Australia, although not recorded. 
 
 Hont-plants and parts affected. — The disease causes the most 
 injurious effects when upon the roots and stems of cauliflower* 
 and cabbages, but it is not uncommon to find it upon the leaves 
 of these plants in summer, as well as upon those of turnip and 
 rape. Its appearance above ground on the leaves will account, 
 for its spread from field to field, and shows the necessity for 
 endeavouring to check it early in the season. It seems to begin 
 at the collar or junction of the stem with the ground atid spread 
 downwards and upwards. 
 
 Symptoms. — A plant attacked by this disease is readily recog- 
 nised; the leaves have a sickly withered look, the stem is shrivelled, 
 and the roots become brown and rotten. If a plant is pulled up,, 
 the underground parts show numerous little black points visible^ 
 to the naked eye, which constitute the fructification of the fungus. 
 Even in the seed-beds plants attacked may be recognised by their 
 sickly appearance. 
 
 Effects. — The effects have already been well described by Mr. 
 Molineux. It is in the root particularly that the worst effects are- 
 produced. The tissue decays in large patches, which become- 
 confluent, and soon spread right round. The interior is also 
 invaded, and the woody fibre becomes blackened, and the plant 
 soon dies. The common names given to the disease indicate the- 
 most striking symptoms, but only when they have become very 
 pronounced. " Black Leg," refers to the blsckened appearance- 
 of the stalk and the black ring which is seen on cutting it across. 
 Foot-rot indicates that the tissue is disorganized, and the root ia^ 
 soon unable to support the plant, which quickly succumbs. 
 
 Nature of Fungus causing disease. — The disease is undoubtedly 
 produced by the fungus and the numerous often densely-crowded 
 perithecia or spore cases at the surface are the fructifications of the- 
 fungus. When a section of the root is made numerous hyphas or 
 threads of the fungus are seen ramifying on the tissues, and thus- 
 disorganization of the cells is produced. The perithecia fall away 
 on the decay of the tissues, and thus the spores of the fungus- 
 winter in the ground. Like most fungi this one thrives best irt 
 wet weather, followed by heat, and the worst cases occur when* 
 the seed is put in late, and the young plants are forced along by- 
 excessive watering. 
 
13 
 
 Treatment. — This disease is known in Europe, particularly in 
 France, and the only advice given to growers tiiere is to remove, 
 without delay, all affected plants and burn them, in order to 
 prevent tlie spread of the disease. While this is a most 
 important measure for getting rid of the disease, the examination 
 ■of a number of gardens in the East Brighton district has shown 
 that other precautionary measures may be taken for the same 
 purpose. 
 
 When the stalks are allowed to remain and rot in the soil the 
 tissues become thoroughly disorganized, and the little black spore 
 sacs are detached from the plant and rest in the soil. In August 
 the spores were being produced in countless myriads, and by this 
 means they are just as effectually sown in the ground as is the 
 seed of the, cauliflower or cabbage. There is every reason to 
 believe that this fuugus can only gain acdess to the young plant, 
 as the disease is observed even in the seed-bed. Certain varieties, 
 too, have been observed to be less liable to the disease than 
 others, and this feature will also receive attention. 
 
 Meanwhile the following suggestions may be made : — 
 
 1. All diseased plants should be removed and burnt as soon 
 
 as the disease is detected. 
 
 2. No refuse from diseased fields should be added to the 
 
 manure heap, since the disease is' thereby spread. 
 
 3, Different varieties resist the disease differently, so seed 
 
 should be selected from those varieties which have been 
 most resistant and less easily succumbed to the disease. 
 
 4, The seed-beds should be treated,. preparatory to sowing, 
 
 with a fungicide such as sulphate .of copper. In dealing 
 with a serious fungus disease of the tobacco plant, I 
 found that treatment of the seed-bed on the same day 
 as the seed was sown was very effectual. A strong 
 solution of bluestone was used, at the rate of 4 lbs. to 
 50 gallons of water ; and Bordeaux mixture, at the 
 rate of 2 lbs. bluestone and 2 lbs. quicklime to 10 gal- 
 lons of water, has likewise been tried. 
 
 (Plate I., Figs. 1, 2, 3, 4.) 
 
PLATE II. 
 
 Club-root ok Botca. 
 
 (^Plasmodia phora brassicae.) 
 
 This specimeii of Cauliflower Eoot was obtained on 7th Sep- 
 tember, 1900, and showed a single large swelling with several- 
 rootlets coming off above it. 
 
Plate II. 
 
 , II 
 
 6X'Bnttlefaartt-,cleL 
 
 V 
 
 CLUB ROOT , 
 
 ■(Plasmodiophora brassicae, Wor. ) 
 
15 
 
 2. CLUB-ROOT OR BOTCH. 
 
 {Plasmodiophora brassiccB, Wor.) 
 
 This disease was fully treated in Bulletin No. 14 of the De- 
 partment of Agriculture, issued in December, 1891, and that 
 report is practically reproduced here, with the addition of the 
 most modern methods of treatment. The distribution of this 
 disease is co-extensive with the plants themselves, and has been 
 known in Europe for over a century, where it has various names 
 besides club-root, such as finger-and-toe, anbury, and hernia, or 
 rupture. Locally it is usually called the botch, because, I pre- 
 sume, the plant is considered to be spoiled, or botched by it. 
 
 Host-plants and parts attacked. — In treating of plant disease 
 due to fungi it is important to recognise the host- plants. The 
 parasitic fungi live at the expense of the plants which they in- 
 fest, and for convenience their feeders are spoken of as their 
 hosts. When we know the various hosts of any particular fungus, 
 then the kind of plants on which it lives are recognised, and the 
 weeds of any such should not be allowed to flourish in the hedge- 
 rows or headland's In this instance the most important are the 
 cabbage and cauliflower, the savoy and kphl-rabi, the turnip and 
 rape, besides other cruciferous plants, such as the stock and candy- 
 tuft, the shepherd's purse, and hedge mustard, &c. This is a 
 disease essentially of the roots, but it is also found on the 
 leaves. 
 
 Symptoms. — The plants soon begin to droop and die when the 
 roots get clubbed. Clubbing may commence in the early spring, 
 even with young seedlings, and the swellings, which sometimes 
 attain the size of the fist, become much larger on the main roots 
 than on the lateral ones. The drooping leaves and Blunted growth 
 above ground plainly indicate a diseased condition, and usually 
 no flowers are produced, although there may be formed occasionally 
 a small brown stunted head of flowers. Exceptional cases are 
 known where the general vigour of the plant was sufficient to 
 overcome the clubbing of the root, and produce a fairly-sized head. 
 The club itself is too well known to those troubled with it to 
 require description. Instead of the well developed and shapely 
 main root, with its numerous rootlets penetrating the soil in 
 search of the necessary food and moisture, there is a swollen mass, 
 which may be either more or less compact or broken up into 
 numerous irregular swellings. The colour of the tissue varies. 
 Early in the season it is whitish, like a mealy potato, later it turns 
 a dirty white and mottled, and towards the middle of winter it 
 becomes darker still. 
 
16 
 
 Conditions favnuring the Disease. — Theconditions under which 
 ■club-root is deyeloped are not too well defined, so it will be in- 
 -structive to describe them as they occur in a large market-gar- 
 -deaing district sucli as East Brighton. 
 
 (o) Natvre of Soil. — Where the soil was of a deep and some- 
 what moist black sandy nature, and free from stagnant water, there 
 was generally no club, but in heavy shallow land with a clay 
 bottom and stagnant water allowed to remain there the club was 
 Tery prevalent. I met with a striking illustration of this on one 
 of my visits. At a particular portion of the field a couple of rows 
 of cauliflowers were badly clubbed for a short distance, causing 
 the spot to look comparatively bare, while all around and beyond 
 in the same rows there was a vigorous growth. On inquiring 
 the reason of this, 1 found tbat in making a ditch at the bottom 
 of the field the clay dug out was spread over this particular spot. 
 The clubbed roots were positively plastered up with clay, and 
 .a healthy growth was impossible under such circumstances. Of 
 the value of drainage it is unnecessary to speak in its two-fold 
 •character of aerating the soil and allowing the sun's rays to act 
 upon it, instead of being simply absorbed by the stagnant water. 
 Moreover, the presence of oxygen in the soil increases the depth 
 to which roots will penetrate in search of food. The drained land 
 has the advantage even with the club, although some land in this 
 district thoroughly drained is still troubled with the disease. 
 
 (6) Kind of Manure. — Stable manure is that generally applied. 
 Superphosphate is also used with beneficial results, the report 
 being that club is not nearly so bad wherever it is used. This is 
 ■contrary to the experience of Professor Jamieson of Aberdeen, 
 who found that manures containing sulphur and chlorine favoured 
 the fungus. Some interesting experiments carried out by him 
 went to show that club-root in turnip is encouraged by sulphur, 
 since the resting-spore of the club-fungus finds its most congenial 
 pabulum in the sulphur of the manure. This is contrary to the 
 generally received opinion of sulphur being always inimical to 
 the growth of fungi, and the combination of lime and sulphur, 
 which has been suggested for combating the disease, would not 
 seem to be applicable. Although the experience here tends to 
 show that superphosphate keeps down the disease, in his experi- 
 ments the superphosphated plot was the worst of the lot. 
 
 (c) Time of appearance of Disease. — It generally appears about 
 the beginning of March, in a form readily recognised by the 
 grower, associated with the early rains, arid lasts until the latter 
 end of June or beginning of July. It may, however, occur much 
 later, as the specimen drawn was taken from a field in September. 
 
17 
 
 (d) Preceding Crops. — In one garden visited farming opera- 
 tions liad been previously carried on, and only hay and potatoes 
 grown. On planting cauliflower one part of the land developed 
 club, while another part was free from it without any evident 
 cause. 
 
 (e) Variety of Plant. — It appears that it is immaterial whether 
 the varieties are early or late as far as the club is concerned, but 
 the discovery of a club-proof turnip should direct attention to the 
 selection of varieties of cabbage and cauliflower with the same 
 object in view. 
 
 I have received a small quantity of the seed of the so-called 
 club-proof turnip for trial through the kindness of Professor 
 Wright, of the West of Scotland Agricultural College; and he 
 remarks^" This turnip was put on the market a few years ago 
 which was said to be proof against the disease. Our trials 
 showed it to be, more resistant to the attack of the fungus than 
 other turnips, but not quite proof against it, and in other respects 
 it was rather an inferior turnip. 
 
 The conditions of the development of the disease naturally lead 
 us to consider its cause. 
 
 Cause of Disease. — It need hardly be said that various causes 
 have been assigned for this disease, but only a few need be 
 selected for consideration. It is sometimes attributed to insects, 
 and I would not have thought it necessary to notice this discarded 
 notion but for the fact that even in such a standard work as 
 Nicholson's Dictionary/ of Gardening clubbing is said to be due 
 to insects. 
 
 There are sometimes rounded thickenings or galls about the 
 size of a marble on the stems of cabbages, just about the collar 
 or junction with the soil, due to the larvae of a weevil, but this 
 has nothing to do with club-root, although the insect-galls may be 
 found on the same plant. Besides, the galls are hollow and con- 
 tain the grubs, while the " clubbed " parts are solid when young. 
 The decaying roots, which have a very disagreeable smell, soon 
 become breeding places for insects, and thus the mistake may also 
 arise as to their being the cause. It has been generally accepted 
 by farmers that clubbing was due to a degeneration of the plant — 
 a sporting condition, in which the plant reverted to a considerable 
 extent to its original wild form. With good seed and careful 
 cultivation this tendency to reversion or sporting is checked, and 
 the pl^nt is encouraged to produce a single succulent tap-root. 
 Acting on the sound prindiple that the remedy lies in the rempval 
 of the cause, those who looked upon degeneracy as the cause 
 regarded the deficiency of available potash in the soil as being 
 
 U179. B 
 
responsible for this weakness or reversion. Therefore they recom- 
 mended the application of lime, which sets free the potash in the 
 soil for the use of the growin>; plant. But while one set of facts 
 appear to point to degeneracy of the plant as the cause, there is 
 another set which point in the opposite direction. The disease 
 appears frequently where the most approved system of cultiyntion 
 has been adopted, and we hare observed it where the condition of 
 the soil and the practical skill of the cultivator should have been 
 proof against degeneracy. ' 
 
 And this leads me to the second cause assigned — that the 
 disease is due to a fungus, a conclusion borne out by the microscope 
 and various infection experiments. We owe our knowledge of 
 this parasitic fungus to a Eussian botanist named Worouin, who, 
 in 1876, after three years' constant observation and experiment, 
 was able to announce the true cause of clubbing. If a section is 
 made across one of the root swellings sufficiently thin to be 
 examined under the microscope, the view shown in Figs, 5 and 6 
 represent it. 
 
 The fungus does not form innumerable interlacing filaments, as 
 is usually-the case, but a slimy mass of protoplasm, of a yellowish 
 colour, inside the cells of the cauliflower or other plant attacked. 
 It is usually in the form of strings, and the cells are enlarged 
 which contain it. Moreover, the protoplasm has the power of 
 movement, and when it is free can move about as if it were an 
 animal. These fungi are known as Slinie-fungi, and the best 
 known representative is the yellow creamy-like mass found on old 
 tan-pits, and commonly known as "Flowers of Tan," When the 
 spent tan has been applied to plants, this fungus has been known 
 to move up the stem. This naked moving mass of protoplasm is 
 technically known as a Plasmodium, and the name given to this 
 fungus by its discoverer is Plasm odiophora or Plasmodium- 
 bearer. 
 
 Life-history of Cltik Fungus — Beginning with the plasmodium 
 (Fig. o) or mobile mass of protoplasm, which is the living sub- 
 stance, we have seen that it is contained in the cells of the clubbed 
 root, causing them to enlarge considerably, so that the net result 
 is a general swelling or clubbing of the entire mass. Subsequently 
 the Plasmodium breaks up into innumerable rounded spores 
 (Fig. 6), so that the cells hitherto taken up with the slimy proto- 
 plasm are now packed with spores. These spores are reproduc- 
 tive bodies, by means of which the life of the fungus is main- 
 tained till the succeeding season, so that when the next crop ia 
 sown they too are ready to germinate. This takes pkce as shown 
 in Fig. 7, and they are set free in the soil in myriads when the 
 parts containing them decay. 
 
19 
 
 The contents of each spore, when moisture is present, bursts 
 through Mild ultimately becomes free, leaving its case behind. 
 It is now able to move about by means of a projecting delicate 
 thread-like piece, of its substance, called a ciliutn, and from its 
 animal-like movements gets the name of zoospore. Without 
 moisture, of course, this process of germination could not take 
 place. These zoospores cannot long remain free, since from 
 their unprotected condition they must either find a host or 
 perish. So Coming into contact with the young roots of the 
 crucifer they find their way inside, m6st probably through the 
 root-hairs. Tlie tissues must be tender in order to allow of the 
 entrance of the spore-mass, and it is said that the plants are most 
 susceptible to disease during the first three weeks after germina- 
 tion. Once within the tissues the plasihodia tbrive upon the 
 material which the young plant intended for its own use, and 
 so the disease arises, and may be propagated in a similar fashion 
 from year to year. In dry material the spore can retain its vitality 
 for more than a year (some say several years), so that the completa 
 life-history — plaemodium, spore, zoospore, and plasmodium again 
 — need not necessarily occur in the one season. Every practical 
 cultivator will now see that if club-root refuse is left on the field 
 or allowed to rot as manure and used, he is as effectually sowing 
 the seed of the disease as in sowing wheat he produces a crop of 
 grain. The spores become scattered through the soil, and are 
 ready under favorable conditions to infect any young plants 
 grown there. 
 
 Injection Experiments. — In treating of the cause of this 
 disease it may have occurred to some that because the fungus is 
 found in club-root, it does not necessarily follow that it is the 
 cause of the disease. It may rather have been a consequence 
 due to the fungus taking up its abode there after the root had 
 become disorganized. To answer such questions infection experi- 
 ments are undertaken, whereby otherwise healthy plants are 
 infected and the disease produced. Thus Woronin, already 
 referred to, sowed cabbage seed in soil containing decayed club- 
 roots, and watered them with water containing the spores as 
 well. In almost every instance the roots were clubbed, while 
 similar plants in pure soil and v^atered with distilled water 
 showed no trace of the disease. Such experiments have been 
 often repeated in various forms with the same result ; and the 
 conclusion to be drawn is that the fungus is necessary to the 
 production of the disease, and where there is no such fungus 
 there will be no such disease. 
 
 Preventive Measures."^^ ow that we know the nature and life- 
 history of the parasite causing the disease, we are in a position 
 
 B 2 
 
20 
 
 to suggest some means of warding off the attack ; and It is found 
 that to leave cabbage stumps in the field, to feed them to live 
 stock, or to throw them on the manure-heap are three of the best 
 possible methods for propagating and spreading the disease. 
 
 1. The application of unslacked or recently slacked lime at 
 the rate of from 35 to 75 bushels per acre will considerably 
 reduce or altogether prevent the disease. It is found that 
 " clubbing " seldom occurs on soils rich in lime unless diseased 
 plants have been_transplanted to it, while in sandy and clay soils 
 deficient in lime the disease is often very severe. When lime is 
 applied in the drills shortly before the sowing of the seed the 
 attack is considerably modified, though dressings given not less 
 than two years before the growth of the crop generally act as an 
 efficient preventive. 
 
 2. All diseased and decaying plants are a possible source of 
 infection, and should be removed and burnt as soon as possible, 
 or at least placed in some out-of-the-way corner where they will 
 not afterwards be transferred to the cultivated ground. Ploughing 
 in the refuse is simply perpetuating the disease, and on no 
 account should diseased plants be added to the manure-heap. 
 
 3. Seedlings and young plants affected with the disease should 
 be removed and burnt as early as possible, in order to prevent 
 the formation of spores. Start with healthy plants, and only 
 plant from beds in which the disease does not occur. Plants 
 examined on 14th May showed only plasmodia in their cells, 
 while plants from the same field examined a month later showed 
 only spores. 
 
 4. Alternation of crops should be adopted, thus introducing 
 some other kind of plant on which the fungus does not prey. It 
 is not always convenient to adopt this plan, but where " clubbing " 
 is bad it is desirable to crop with other than cruciferous plants 
 for two or three seasons. It is generally recognised by market 
 gardeners that planting the same crop too often on the same 
 groilnd encourages the disease, and the reason is evident from 
 the disease being spread by means of spores in the soil. This 
 disease is seldom troublesome ou land which has not grown 
 cabbages and cauliflowers or allied plants for a few years. 
 
 ^ 5. Clean cultivation should be rigorously carried out, for the 
 disease may start in cruciferous weeds such as hedge mustard, 
 charlock or wild mustard, &c., and thus become established in 
 the soil and spread to cultivated plants. 
 
 6. Land affected with this disease should be isolated as much 
 as possible, until a good dressing of lime ia applied to it ; for it 
 has been proved that infected soil may be carried to uninfected 
 land on tools, cart wheels, and even the boots of the workmen. 
 
21 
 
 Sour soil encourages the disease, and the best kind of 
 manure to use to check it is a matter to be settled by carefully 
 conducted experiments. But the important thing, after all, is that 
 the intelligent market gardener may be led to try such ways and 
 means of coping with the pest as are suggested by the nature of 
 the disease and the life-history of the parasite. 
 
 (Plate II., and Figs. 5, 6, 7.) 
 
PLATE III. 
 
 White Eust. 
 
 {Albugo Candida,') 
 
 The Cabbage Leaf is seen to be plastered over with white 
 patches, at first porcslain-like and polished until the skin bursts, 
 when they become powdery. 
 
Plate III. 
 
 CCBnttlebank,del 
 
 WHITE RUST 
 < Albugo Candida, Kun|;z.) 
 
23 
 
 8. WHITE BUST. 
 
 (Albugo Candida, Kuntz. Cystopus oandidus, Lev.) 
 
 This fungus is very common, and attacks cruciferous plants alj 
 over the world ; but it is not regarded as a serious disease with 
 us, and will therefore be briefly treated. It is very common on 
 weeds here, such as the shepherd's purse and hedge mustard, 
 and it is principally the cabbage which is affected, especially 
 when growing in moist situations. If there is a dry March, 
 which weakens the plants, followed by good rains, then this 
 fungus is likely to occur. 
 
 Although commonly called White Rust, the fungus concerned 
 does not belong to the Rust family, but is rather related to the 
 division which includes the Potato Diseiase and the so-called 
 "Blue Mould" of tobacco. 
 
 Host-plants, and parts attacked, — This fungus attacks all 
 parts of the plant above ground, and usuajly causes them to be 
 much swollen and distorted, so that they are easily recognised, 
 both from their appearance and white colour. The stems, leaves, 
 flowers, and fruit are all liable to attack, but it is the leaves 
 which attract most attention from the grower. 
 
 Among cultivated plants it occurs on the cabbage and cauli- 
 flower, the turnip and radish, and it is very common on cruciferous 
 weeds, such as shepherd's purse. 
 
 Distribution. — It is world-wide in its distribution, and wherever 
 the cabbage family is grown there it flourishes. The " Kerguelen 
 Island cabbage" is exempt from it in its native home, probably 
 on account of the unfavorable climatic conditions, but whenever 
 it is grown elsewhere it suffers severely from the disease. 
 
 Symptoms. — Perhaps there is no fungus disease more familiarly 
 known than this one. Wherever there iff a kitchen garden it is 
 liable to appear, and the appearance of the leaves, as if sprinkled 
 with whitewash, at once arrests attention. 
 
 If the stem is attacked it is swollen and distorted, and covered 
 more or less with white streaks and blotches. The leaves are 
 also splashed with white, and these elongated swollen patches are 
 at first porcelain-like and polished in appearance, from the fungus 
 being produced beneath and raising the epidermis. The skin at 
 length bursts, owing to the pressure from beneath, and a fine 
 white powder escapes, consisting of the conidia, or reproductive 
 bodies of the fungus. 
 
24 
 
 Effects. — The swelling and distortion produced by the fuagus 
 is an unhealthy state of the tissues, and unfits whatever part is 
 attacked for the proper performance of its functions. The leaves 
 turn yellow around the diseased patches, and ultimately premature 
 decay sets in. Infection only takes place during the seedling 
 stage, and it is sometimes so severe as to sweep them off, while 
 if the flpwer ifi attacked there is no formation of seed. The 
 fungus invariably damages the affected plants and diminishes the 
 yield, whether it be of leaf or flowers or seed. 
 
 Nature of Fungus causing Disease^ — The fungus producing 
 the well-known appearance has long been known and studied, 
 It has a very interesting life-history, which it is necessary 
 to understand for the proper treatment of the disease. The 
 white pustules are caused by the cojiidia being produced, 
 in dense masses beneath the epidermis at these spots. 
 They are in chains, and finally becoming free, rupture the 
 epidermis and appear on the surface as a delicate white powder. 
 This light white powder is readily carried by the wind or rain, or 
 even birds and insects, to fresh plants, and thus the disease i." 
 spread. The contents of each conidium, when it is mature and in 
 the presence of moisture, breaks up into several portions, each of 
 which is able to move about in the damp' by means of delicate 
 projecting threads, called cilia. When these moving bodies, 
 known as zoospores, reach the tissue of seedling plants, they enter 
 in by means of the little mouths or stomata, and thus start the 
 disease. 
 
 This fungus has another means of reproducing itself in order 
 to tide over the winter and be prepared to start afresh in the 
 spring. This it does by means of oospores or egg-like bodies, 
 which fall to the ground through the decay of the tissues and 
 remain there during the winter, until wet weather in the spring' 
 causes them to germinate. Zoospores are produced as in the first 
 instance, but in much greater numbers, and finding their way to 
 the seed-leaves of young plants, infect them. Thus the fungus 
 is able to produce spores in the course of the season, as well as 
 in the spring, and these spores, although similar, are produced in' 
 different ways. ■■ . .: 
 
 1. Conidia are produced in chains, which burst through the 
 epidermis, and on germination divide into — 
 
 2. Zoospores, w;hich penetrate the,tissues of seedling plaut^. , 
 
 3. Oospores, or resting spores, are formed later on, and only 
 reach maturity when the plants bearing tliem have decayed. In 
 the spring they give rise tq—r 
 
 4. Zoospores, which behave like the others. 
 
25 
 
 The above life-history shows how well the fungus is provided 
 with means for perpetuating tlie species ; and even if the 
 winter should be severe, the oospore with its thick coat is well 
 able to resist the changes of temperature and remain dormant 
 until the spring. 
 
 Treatment. — 'Since this fungus is produced at first under the 
 skin, and can only scatter its spores by rupturing it, attention 
 should l)e paid to the slightest swelling or distortion, so that 
 diseased plants may be destroyed before the fungus comes to ma- 
 turity. Further, since the fungus can only gain an entrance into 
 young plants, and the spores, in fact, cati only germinate upon 
 seed-leaves, care should betaken to prevent the spores reaching 
 the young plants; and this can only be done by destroying all 
 diseased plants ; and no decaying Cabbage or Cauliflower refuse 
 should be alloTved to remain on the ground during the winter to 
 form a harbor for the fungus. The resting spores have been found 
 on cruciferous weeds, and thus the fungus is tided over the winter. 
 The burning of diseased and decaying plants is the main remedy 
 for preventing the re-appearance of the disease. 
 
 The measures to be adopted may be summarized as follows : — 
 
 1. Destroy all diseased plants as soon as detected, and ako 
 
 all cruciferous weeds. 
 
 2. No Cabbage or Cauliflower refuse should be allowed to 
 
 remain on the ground during the winter. 
 
 3. Change of crop on infected ground to some other family 
 
 of plants than crucifers tends to lesson the White ilust 
 by starving it out, and Cabbages and Cauliflowers 
 should not be grown for two years in succession on 
 ground >vhere the disease is prevalent. 
 
 4. Since infection only takes place in seedlings, the greatest 
 
 care should be taken to plant out only those which show 
 no indications of disease. 
 
 (Plate III. and Fig. 8.) 
 
PLATE IV. 
 
 EiNG-SPOT OF LkaF. 
 
 (Sphaerella brassicicata.) 
 
 The Cabbage Leaf shows the spots on upper surface marked 
 by concentric rings with the minute densely crowded black 
 perithecia. 
 
 Iij the right-hand lower corner a spot is shown slightly 
 enlarged with the concentric rings Tery clearly shown. 
 
' ? 
 
 ^ 
 
 # 
 
 Plate IV.. 
 
 i 
 
 • 
 
 i 
 
 RING SPOT 
 (Sphaerella brassicicola, Ces. and De Not. }■ 
 
27 
 
 4. KING-SPOT OF LEAF. 
 
 {Sphcerella brassicicola, Ces. and De Not., and Pliyllosticta 
 brassioicola, new species.) 
 This is a disease Tvhich is very common on the leaves of both 
 Cabbages and Cauliflowers, but since it only occurs on the older 
 leaves, and especially those which are already fading and wither- 
 ing, it is not regarded as of serious import. The young and fresh 
 leaves of the Cabbage are always free from it, and the head of 
 the Cauliflower seems to attain its full size ; still the outer and 
 older leaves prematurely decay, and therefore the plant is bound 
 to suffer from defective nutrition. 
 
 Parts attacked. — I have only met with it on the leaves, but it 
 is found occasionally on the fruits, on the Continent of Europe. It 
 is essentially a leaf-disease, and occurs generally when the leaves 
 begin to wither. 
 
 Distribution. — It is found in various countries of Europe, 
 France and Germany, Italy and Belgium, and Hungary. Although 
 •only recorded from Victoria, it probably exists in the other 
 ■States wherever Cabbages and Cauliflowers are cultivated on a 
 large scale. 
 
 Symptoms. — It is easily recognised- from the circular patches 
 studding the leaf, and I have named it "Ring-spot" on that account. 
 The spots are generally about three-eighths of an inch in diameter, 
 greenish towards the margin, and of a dirty brown towards tha 
 ■centre. A very conspicuous feature is the ininute densely crowded 
 black points, more or less covering the surface, which constitute 
 the fructifications of the fungus. The spot is also marked by 
 concentric rings, more particularly towards the outer margin, and 
 altogether is so well marked as to be quite distinct from anything 
 «lBe. 
 
 Effects. — The effects of the fungus have already been referred 
 to. It hastens the withering of the leaf and causes it prematurely 
 to fall. Too much work is thrown upon the leaves which 
 remain, and the plant suffers. The disease is so common in 
 many gardens, and is so associated with the older withering 
 leaves, that it is coinmouly regarded as a natural process of decay. 
 
 Nature of Fungus causing Disease. — The fungus associated 
 with the spots is undoubtedly the cause. Like so many other fungi, 
 this one begins at a definite centre and gradually spreads around 
 until a circular patch of tissue is invaded by it. The hyphae or 
 threads of the fungus ramify through the substance of the leaf, 
 then towards the surface they became rauqh divided and bear the 
 innumerable minute black fruit-bodies, or perithecia. These are 
 
28, 
 
 of two kinds—one smaller, containing innumerable short straight 
 spores, and most common in autumn and early winter ; the other 
 somewhat larger, and containing a number of little sacs, in each 
 of which are packed eight spores, and these escape when ripe by 
 a little opening or mouth at the top of the perithecium. 
 
 The one stage of the fungus {Phyllosticta) appears on the 
 still green fnlly formed leaves, and in the late autumn it is the 
 only one present. Then towards the beginning of winter the 
 complete or second stage appears {Sphmrella), intermixed with 
 the other on the dead and often fallen leaves. It is not unusual 
 among fungi to have different reproductive stages adapted for 
 different seasons of the year — iu this case, one to spread the 
 disease among the still green leaves, and the other to form a 
 resting stage, so tliat the fungus may be carried over to next 
 season and start again in the spring. Considering the vast num- 
 bers of the spores, combined with their minute size and lightness, 
 it is not surprising that they are so freely distributed, and that 
 the diseased rings are so very common, sometimes almost over- 
 spreading the entire leaf. 
 
 Treatment. — Although no experiments have been carried out 
 with this particular fung«s, there aro various measures suggested 
 by its nature and life-history which will tend to check its spread 
 and lessen its injurious effects. 
 
 1. Only perfectly healthy plants should be planted out from 
 
 the seed-bed, so that they may be better able to resist 
 the inroads of the disease. 
 
 2. Diseased leaves should be removed and destroyed as soon 
 
 as 'observed, so that the fungus may not be allowed to 
 reach the fruiting stage and scatter spores. 
 
 3. Such litter siiould not be added to the manure heap, for 
 
 there the fungus will reach its full development, and be 
 scattered over a wider area. 
 
 4. Well-draiiied land favours the healthy growth of the 
 
 plant, and is inimical to the fungus,.. while .sour wet 
 badly aerated ground provides the most suitable con- 
 ditions for the growth of the fungus, and at the same 
 time predisposes the plant to attack. 
 
 5. Seed, should only be gathered from such plants as are 
 
 free from disease, and care should be taken that none of 
 the seed-pods are affected. 
 
 By taking such precautions as the above, the disease will be 
 limited in its spread, and may gradually be exterminated. 
 (Plate IV. and Figs. 9, 10, 11.) 
 
PLATE V. 
 
 Putrefactive Mildew. 
 
 {Peronospora parasitica.') 
 
 A. On young plants early in season — These leaves were 
 obtained from young Cabbage plants on 11th September, 1900. 
 
 The top leaves show the effects of the fungus on upper and 
 under surface of still green leaves, and tlie lower leaves are com- 
 .pletely .destroyed by the fungus. 
 
 N.B. — These plants were grown under bell jars, and so were 
 kept continually in moist air. 
 
Plate V. 
 
 PUTREFACTIVE MILDEW 
 (Peronospora parasitica, De By. T 
 
PLATE VI. 
 Putrefactive Mildew. 
 
 {Peronospora parasitica.) 
 B. Appearances on mature plants, though young plants in seed 
 beds present similar symptoms — 
 
 (a) Still green leaf with blackened patches, frayed at the 
 edges, y 
 
 (6) Portion of withered leaf, showing spots with dark- 
 brown or black margins and yellowish or greyish 
 centres. 
 
 (c) Portion of badly diseased leaf much blackened but 
 partly eaten by slugs. 
 
Plate VI 
 
 PUTREFACTIVE MILDEW 
 (Peronospora parasitica, De By.> 
 
33 
 
 5. PUTEEFACTIVE MILDEW. 
 
 (^Peronospora parasitica, De Bary.) 
 
 This is a disease which is very generally distributed on Cruci- 
 ferae, and causes more or less deformation and discoloration of the 
 pans attacked. It may occur along with other fungi, such as 
 the White Rust, and produce putrefaction of the tissues. 
 
 Plants and parts attacked. — A.mong Cultivated plants it is 
 found upon the Cabbage and Cauliflower, Turnip and Badish, 
 Rape and Cress, and on garden plants siich as Wallflower and 
 Nasturtium. It occurs on the leaves and inflorescence, as well 
 as on the stems, as a thin white bloom, and it is confined to 
 cruciferous plants. It is so common on different species of this 
 family that 56 are recorded as being affected with the fungus. 
 
 Distribution. — It is not at all uncommon in Britain and 
 America, and occurs also throughout Europe. 
 
 I have only observed it in Victoria, but it doubtless exists in 
 the other States. ' 
 
 Symptoms. — In early spring it occurs as a delicate white or 
 greyish mould on the under surface of the leaves, the affected 
 parts usually appearing yellowish, apd soon becoming dry and 
 withered. (Plate V".) Later in the season, towards the end of 
 December, the fungus was found presenting cuj-iously different 
 ofEects upon the leaves, which were studdfed with irregular light- 
 coloured spots and patches, with dark margins and occasional 
 black points. The spots sometimes ran together till the whole 
 leaf presented a mottled appearance. Exactly similar appearances 
 (but without any indication of the presence of the fungus) were 
 found on leaves of mature plants in July and August (Plate 
 VI.), and were at first thought to be due to the bacterial disease 
 known as "Black Rot" in America, since at that time only 
 bacteria could be obtained from the spots. These bacteria were 
 found by Dr. Cherry, of the Bacteriological Laboratory, to some- 
 what closely resemble those described by Dr. Erwin F. Smith, 
 Department of Agriculture, U.S.A., as the cause of the "Black 
 Bot." However, on submitting actual specimens to Dr. Smith, 
 he unhesitatingly pronounced the disease to be quite distinct from 
 anything he had previously observed. The discovery in early 
 summer of the fungus in great profusion in extensive seed-beds, 
 as well as in private gardens, in widely-separated parts of the 
 State, constantly upon these spots, and never present without the 
 'spotting and blackening of the leaf, furnished conclusive proof 
 that the so-called Black Rot of our Victorian market-gardeners is 
 merely the after effects of the Peronospora. The variation in the 
 symptoms in spring and summer are probably due to the differing 
 
 11179. ° 
 
u 
 
 Weather couditions. The inability to obtain resting spores is not 
 regarded as of importance, since in this state these bodies, in 
 kindred diseases, are chiefly conspicuous by their absence. 
 
 Nature ■ of Fungus causing Disease. — The cause is a fungus 
 belonging to the same division as the potato disease fungus. 
 If the delicate white mould is examined under the microscope, 
 it is seen to consist of projecting threads which branch 
 repeatedly in a forked manner, and the ultimate branches 
 are pointed and slightly curved. At the apex of each little 
 brancblet a colourless elliptical conidium is produced, giving 
 the appearance of a miuiature tree loaded vs^ith fruit. When ripe 
 they are very easily detached, and the slightest breath of wind 
 will waft them away. The conidia-bearers are so numerous as to 
 give the mould-like appearance to the leaf, and they project 
 through the stomates or breathing-pores of* the leaf. They cor- 
 respond to the fruit-bearing portion of the plant, and if traced 
 inside the leaf they are seen to have their " roots " there. These 
 consist of numerous filaments without any divisions, but branching 
 and spreading everywhere between the cells of the leaf. 
 
 The conidia are ready to germinate as soon as they reach a 
 suitable host, and put forth a germ tube from the side, which 
 penetrates the leaf by piercing the cuticle, and produces the 
 roots and fructification of a new fungus. These conidia are pro- 
 -duced in great profusion during the growing season of the host- 
 plant, commencing at least early in September or the beginning of 
 spring. But the fungus is tided over the winter by means of rest- 
 ing spores known as oospores, or egg-spores, on account of their 
 mode of production. They originate In the interior of the attacked 
 plants from the side of the fungus-filaments, which permeate the 
 tissues and are set free by the rotting of the plant. The resting 
 spores are yellowish-brown in colour, from the membrane which 
 covers them, and they are able to resist the various climatic 
 changes until the spring again comes round, when they wake to 
 new life, germinate, and attack the plants as before. 
 
 Treatment. — 1. The refuse of diseased plants should be de- 
 stroyed, since they harbor the resting spores of the fungus. 
 
 2. Cruciferous weeds should be kept down, since ihey serve as 
 host-plants for the fungus and tend to distribute the disease. In 
 such common weeds as Shepherd's Purse, the resting spores have 
 been found in the decaying remains, so that, both to prevent the 
 spread of the disease during the growing season and its survival 
 during the winter, such weeds should be destroyed as far as 
 possible. 
 
 3. VVhere the disease is detected in young plants, as it may 
 readily be from the yellowing of the leaf on the upper surface, 
 remove the plants gently at once and destroy them by fire. 
 
 (Plates v., VI., and Figs-. 12, 13, 14, 15^ 16, 17, 18, 19.) 
 
PLATE VII. 
 
PLATE VIII. 
 
 
 
PLATE IX. 
 
35 
 
 EXPLANATION OF PLATES. 
 
 PLATE VI r. 
 Black Leg or Foot-rot. 
 Fig. I. — Transverse secticsn throngh diseased stem of cauliflower 
 showing perithecia of fungus seated on margin of 
 split caused by tlie fungus ( X 50 j. 
 
 Fig. 2. — Longitudinal section of diseased stem showing group of 
 perithecia ( x 65). 
 
 Fig. 3, — Transverse section of diseased stem showing perithecium 
 bursting through ( x 65). 
 
 Fig. 4. — -Sinailar section showing perithecia wi(h prominent necks 
 still embedded in the tissue ( X 65). 
 
 PLATE VIIL 
 
 Club-root or Botch. 
 
 Fig. 5. — Transverse section through swollen root of cabbage 
 showing distention of cells, some being empty, others 
 filled with the plasmodium of the fungus ( X 100). 
 
 Fjg. 6. — Similar section showing plasmodium breaking up to form 
 spores ( X 100). 
 
 Yig. 7. — Spores germinating and producing motile zoo-spores 
 ( X t^sm). (After W. G. Smith.) 
 
 *" White Rost; 
 
 Fig. 8. — Transverse section of diseased leaf of cabbage showing 
 masses of spores on surface (x 65). 
 
 PLATE IX. 
 
 Ring-spot of Leaf. 
 
 Fio'. 9. —Surface view of fragment of diseased leaf showing the 
 crowded perithecia ( x 50). 
 
 Fig. 10. —Transverse section of diseased leaf showing perithecia 
 of Sphaerella (x 50 . 
 
 Fio-. 11. — Similar section showing single perithecium oi Sphaerella 
 on left and several of the earlier or J'hi/Uosticta stase 
 at right (x 50). 
 
36 
 
 PLATE X. 
 
 Putrefactive Mildew. 
 
 Figs. 12, 13, 14, 15. — Conidiophores bearing conidia from lower 
 surface of diseased cabbage leaf ( X lOO). 
 
 Fig. 16. — Conidiophore more highly magnified (x 200). 
 PLATE XI. 
 
 PCFTKEFACTIVE MiLDEW. 
 
 Fig. 17. — Surface view of diseased leaf showing blackening of 
 cell-walls ( X 50). 
 
 Fig. IS.^Transverse section of diseased leaf showing blackening 
 of cell-walls ( x 50). 
 
 Fig. 19. — Similar section showing blackening of cell-walls and 
 formation of black rounded masses or " plasmodes " 
 (x 100). 
 
 APPENDIX. 
 
 In every case of fungus disease of catbage and cauliflower 
 described in this pamphlet, it is recommended to destroy the refuse 
 by burning, because the spores of the fungus are preserved in the 
 decaying material. Even growers themselves have come to the 
 conclusion that the disease is spread by ploughing in cabbage and 
 cauliflower stumps affected with " Black Leg," and they recognise 
 the necessity of destroying them, if they are to get rid of the 
 disease. There are certainly difficulties in the way of getting 
 rid of such material by burning, but no doubt some means could 
 be devised of doing so after it is sun-dried. There is a possible 
 way of getting rid of the refuse by means of a Garbage Destructor, 
 the idea being suggested to me by Dr. Gresswell, and I had an 
 opportunity of inspecting a model of the apparatus at Mr. 
 Hesse's, South Melbourne. The apparatus is necessarily an ex- 
 pensive one, and the work would require to be carried out on the 
 co-operative principle, possibly in conjunction with the shire 
 councils, but it is a matter worthy of careful consideration as to 
 whether the outlay would be justified by the results. I can only 
 say that the destruction of the decaying refuse, combined with 
 clean cultivation, would go a long way towards stamping out 
 disease. 
 
PLATE X, 
 
 %'%.. 
 
 ^'K^ ^ 
 
 ^syc^ ". 
 
 
 d 
 
mnqj iiihq,.i PLATE XI. 
 
 
 >*! 
 
 # 
 
 V:^^ 
 
 
 
 o 
 
 o 
 
37 
 
 A recent report- on the Garbage Destructor, by John Monash, 
 M.C.E., is here given. 
 
 [Copy.] 
 
 Australian Buildings," 49 Elizabeth-street, 
 Melbourne, 1st August, 1900. 
 — Hesse, Esq., South Melbourne. 
 Dear Sir, 
 
 Having at your request inspected your model of the Garbage 
 Destructor, having a revolving furnace heated by a tar spray, 
 and having been asked by you to express an opinion upon the 
 mechanical efficiency of such an 'arrangement, I beg to report as 
 follows : — 
 
 You have given me to understand that the full size revolving 
 furnace vrill be 24 feet long and 5 feet diameter, constructed of 
 boiler plate, stiffened by angle irons, and lined with fire-brick ; the 
 whole cylinder resting upon a seribs of fixed rollers, and actuated 
 by tooth-gearing, revolved by steam power. The cylinder to be 
 placed with a slight slope in its length. The charge of garbage 
 entering at the upper end and passing downwards along the 
 cylinder through a zone of intense heat, the non-volatilized 
 materials being discharged at the lower end. 
 
 As requested, I am addressing myself only to the mechanical 
 practicability of this arrangement. On this point I am able to 
 express a positive opinion that the process is practicable, without 
 any question. 
 
 The chief points to be considered are ; — Construction, which 
 is as simple as an ordinary boiler ; lining, which presents no 
 difficulty ; speed of revolution, which can be made quite reg- 
 ulable ; longitudinal thrust, which, being very slight, can easily be 
 provided for ; expansion under heat, which will not in any way 
 aflFect the rotation, or the supporting of the furnace ; and the 
 question of removing a furnace for the purpose of re-lining and 
 substituting a spare furnace, which, with suitable gear, can be 
 speedily accomplished. 
 
 In point of fact, the general question of a revolving furnace is 
 no novel idea, and the principle requires no certificate of possi- 
 bility, as it is already a well-known contrivance for other industrial 
 purposes. The revolving furnace under discussion will, together 
 with a fiill load of garbage, weigh under 10 trsns. To indicate 
 that such a furnace is perfectly practicable, I need only point to 
 the processes in use for some years past, for the calcining of 
 copper ores, in which are used revolving furnaces very similar in 
 arrangement to your furnace, 38 feet long, 8 feet diameter, and 
 holding a charge of 30 tons to 40 tons of ore, without allowing 
 for the dead weight of the furnace itself. The best-known types 
 
38 
 
 of such furnaces are the " Bruckner, " thfe " Oxlantl," aud the 
 " Hocking." In these types, even with the much greater 
 weights, the rotation is effected merely by friction, there being 
 ordinary rails circumferentially around the shell resting upon and 
 driven by rotating grooved wheels. In your proposal you have 
 tooth-gearing, which is even more certain, aud less liable to dis- 
 location. I therefore consider that, in view of the existing 
 practice in these matters, the mechanical success of your proposed 
 revolving furnace is quite assured. 
 
 You also called my attention to your proposal to use the heat 
 of the combusting gases, as they escape from your incandescent 
 zone in the uptake, I o apply it for boiler purposes in the pro- 
 duction of steam fgr the plant itself or other subsidiary purposes. 
 This is also a common and well-known expedient, being found in 
 connexion with the waste heap from foundry cupolas, Bessemer 
 Converters, Reverberatory Furnaces, and many roasting processes. 
 
 Yours faithfully, 
 
 JOHN MONASH, M.C.E., 
 
 Assistant M. Inst., C.E. 
 
 Bj Authority: Robt. S. Brain, Government Trinter, Melbourne. 
 
_^_ Cornell University Library 
 
 aV608.C14M2 
 
 ungus diseases of cabbage and cauliflow 
 
 3 1924 002 904 864 
 
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