JCNE 7, 1917. 



The Florists^ Review 



19 



HE investigations covered 

 more or less briefly in this 

 report were begun August 

 1, 1916. During the first 

 four months much time was 

 spent in visiting rose plant- 

 ings in northeastern United 

 States, making a survey of diseases. 

 This seemed desirable in order to ac- 

 quaint us with the various diseases, to- 

 gether with their range and the extent 

 of injury caused by them in tliis coun- 

 try. With these facts in mind, suitable 

 ])lants and materials have been col- 

 lected for experiments now under way 

 which will prove of the greatest value 

 to growers of roses. 



Old Diseases. 



The survey and correspondence with 

 growers has shown the most important 

 rose diseases, in order oJ importance, to 

 be (1) black spot, (2) mildew, (3) 

 crown gall, (4) stem canker, (5) Phyl- 

 losticta leaf spot, (6) rust, (7) bud rot, 

 (8) other leaf spots. Practically all of 

 these diseases are always present and 

 take from the growers yearly tolls of 

 surjirising magnitude. It is not uncom- 

 mon to find houses with all the plants 

 comjdetely defoliated by black spot. It 

 is unnecessary to mention tlie damage 

 done by mildew, while there is an ever- 

 increasing demand for information re- 

 lating to crown gall, stem canker, rust 

 and bud rot. Unfortunately, little is 

 kudwn regarding the control of most of 

 these diseases and many points remain 

 to be investigated concerning the con- 

 trol of sucli common and well-known 

 diseases as blnck sjiot and mildew. 



A New Disease. 



A new, and wliat appears 

 to 1)0 one of the most im- 

 portant diseases of the rose, 

 has been observed by the 

 writer in visits to rose 

 houses. We are calling it 

 tiie crown canker. Speci- 

 mens have been sent by 

 growers from many parts 

 of eastern United States 

 and from as far west as 

 Missouri. It was first ob- 

 served by the writer in Sep- 

 temlier, 1916, but talks with 

 growers indicate that the 

 disease has been present for 

 possibly four or five years. 

 All varieties seem to be 

 susceptible to the disease. 

 The plant is attacked just 

 below tlie surface of the 

 soil and altliough the dis- 

 ease advances slowly, the 

 death of the })lant is sure, 

 w i t h an ever-decreasing 

 number and quality of flow- 

 ers. 



This disease, which has 

 never been described, is 

 considered of such import- 

 ance that a large jiart of 



the writer's time is being devoted to a 

 study of the life history of the causal 

 fungus and the development of a metliod 

 of control. Several large growers have 

 stated that unless help is obtained they 

 will be forced out of business. 



Will Soon Be Distributed, 



With the disease already known to be 

 present in the houses of ten large grow 

 ers, it is safe to assume tliat otiier grow- 

 ers liave plants similarly affected and 

 that the disease will be widely distrib- 

 uted and increase rapidly in ini])ortance. 

 Steps must be taken immediately to 

 control this disease. Not only is it im- 

 lK)rtant that growers who already have 

 the disease shall be furnished with con- 

 trol methods, but it is even of greater 

 importance that the method of dissem- 

 ination of the fungus be worked out in 

 order that the further spread of the 

 disease be checked. 



What appear to be other new diseases 

 than the one mentioned above have been 

 brought to the writer's attention, but 

 too little progress has yet been made in 

 this investigation to give definite state 

 ments at this time. 



Work on Leaf Diseases. 



The following investigations are un- 

 der way: 



(a.) Black spot. It is planned to con- 

 duct extensive experiments for the con- 

 trol of this disease during the coming 

 season. Plants at the Cornell test gar- 

 den and at the nursery of Cliase Bros., 

 lloneoye Falls, N. Y., will be treated 

 with various fungicides along the lines 

 of recent develoi)ments in jdant disease 

 control. One of the most im])ortant 

 fungicides to be tried is that of finely 



Statement by Rose Society's Secretary 



l.a-.l ><;ir. in rcsixmsc lo ,i Icfi.i- fn.m I'rc>,i(l« nt r»'nn<>< U, of liic 

 VniiTUiiii l{os«' Soiitl.^. tliir(\-t\\<i tlori^t- miUToiislv (Mini rilml.-d 

 t<iuai<l i\u- iii\csti:;alii>ns in roxc Wiscascs \\lii(li u.To carriiMl oti l.\ 

 l>r. I.. M. Mas>cy, «.f tli.- Dipart nicnt i«t I'lant ratliolofi.v, at ( Orncll 

 I niverwit.v. I»r. AFasscv lias put in ion^idcralilc work ou tliis [irotil.ni 

 Wniini; tlio las» >,.ar an<l lias s<>\.ral lines of iincsl i;jatlon well under 

 \\;\\. M is the feelinj; of llie ollleeis of the American Hose SoeietA thai 

 l>r. ^lassev shoiiM conliniie his work diirin;; the eoniiiifj year, as \va>- 

 oiitlined in tlu- iiro.ject <if a year ai;(). At (hat lime it was Htated that 

 it was expe<'t<'d the inveslia;ation would he on a two-.\ear ay^rcement. 

 I/ast year the American Hose Society pledged ilself to sii|i;>ort Dr 

 Massey while in the tiehl one-fourth of llie time, and that (he eosi 

 would not evoeed SI. (Kid, of whieli sum i^.lOd the first >ear and S.'.ld 

 (he second > «>ar would he for travcliiiir and <i(li<'r special expenses 

 I'he rest of tin- ex|)ensps of the ii.\ est i^at ion ha\e heeii lioriie l>\ 

 Cornell I ni\<'rsity. 



Dr. Masse>- carries on the major part of tlie outside woriv <luriiiu 

 his \a<a(ion periods, when he is free from c<dle!;e duties, and «'an 

 visit commercial ranffes. I.almratorv research is earried on diirinj; the 

 culleKC jcar. 



On (his pa,s;e there appears a summary of a preliminary report of 

 l»r. Massoy's wor(». It will he understo«id from Ihe nature <if the 

 proje<'t that definite resiiKs cannot h»' jiiven in so short a time. It 

 seems, however, that Dr. Masse.v's work durim; the last year has 

 ojii-neil up some won«lerfiilly valuahle lines of investigation, wiiieh 

 slioiilil he continued. 



It is lnii)cd that n lartje numher of men interested in rose srrowinK. 

 who did not contrihiite to the work last >ear. ma> feel intere^ifed to 

 do their part this year. All siihseriptioiis sliould he sent to K. A, 

 AMiite, sjM'relary, American Kose Society, Ithaca. N. Y. 



ground suljiliur ap[)lied in tlic form of 

 dust. Suitul)le plants Iiavc been ob- 

 tained and are now growing in the 

 greenhouse at Cornell for similar experi- 

 ments for the control of black sitot un- 

 der glass. 



(h.) Mildew. Expiirinicnts for the 

 control of mildew tlirough the use of 

 finely ground sulphur used as a dust on 

 hotii indoor and outdoor roses. 



(f.) I'iiylloslicta leal'spot. A study 

 of the life history of the causal organ- 

 ism is now being made. This is one of 

 the most important leaf -spot diseases of 

 ramblers and metliods of control will be 

 tried during tlie coming season. 



Work on Root Diseases. 



(d.) Crown gall. Some 200 healthy 

 plants have been obtaiinMl to be inocu- 

 lated with bacteria causing this dis- 

 ease. These plants will be grown to de- 

 termine the effect of the disease upon 

 the plant, there being a divergence of 

 opinion as to just how much damage is 

 done. 



(e.) The new root or crown disease, 

 crown canker. Extensive experiments 

 for the control of this disease are now 

 under way. It is probable that tiie fun- 

 gus lives in the soil and that successful 

 treatments will be along the line of soil 

 sterilization and the practice of sanita- 

 tion in the houses. Sonic ."lOO rose plants 

 have been obtained and are now grow- 

 ing in the greenhouses at Cornell for 

 these experiments. Much time is being 

 spent in working out tlie life history of 

 the cnusal orgauisni, as such informa- 

 tion is essential for a couiprchensive 

 study of control methods. 



(f.) Fungi and bacteria causing other 

 diseases of roses are lieing stuilied in 

 culture. These organisms 

 lia\e been isolated from 

 diseased material (dit.-iined 

 from growers. Tiieir jiatlio- 

 genicity will be tested and 

 control experiments c, o u - 

 iiu<-t(Ml where the organisms 

 [•rove parasitic and the im- 

 portance of the disease v,-ar- 

 r.ints such action. 



Can't Stop Now. 



It will lie seen from the 

 ;ibo\(' statements that while 

 there is but little yet to re 

 I'l.it ill the line of results in 

 ■eiitri.l, still considerable 

 fu-dgress lias been mad«> and 

 the foundation laid for ex 

 periments for tlie control of 

 diseases which arc of ex 

 treme importance to the 

 growers of ro-<es. There is 

 every reason to expect that 

 another year's work will 

 bring results upon which 

 proved and definite advice 

 may be furnished tlie grow- 

 ers for the solution of their 

 rose-disease problem<^. 1 1 

 is hardly necessary to add 



