NOVBMBEK 2, 1916. 



The Florists' Review 



15 



INVESTIGATION OF DISEASES. 



For tlie American Bose Society. 



A special and extensive investigation 

 of the diseases of roses has been under- 

 taken by the department of plant 

 pathology, Cornell University. This 

 work, which was begun August 1, 1916, 

 is being conducted in cooperation with 

 the American Rose Society, whose mem- 

 bers have contributed towards the 

 financial support of the undertaking. 



During the last three months much 

 time has been spent in visiting rose 

 plantings in the northeastern United 

 States, making a survey of diseases. 

 The gardens and greenhouses of some 

 thirty-five rose growers have been vis- 

 ited. The number and extent of the 

 diseases present have been noted and 

 specimens taken for further study. 

 Growers have also materially aided the 

 work by sending in specimens. These 

 specimens have been examined and the 

 grower advised as to the cause and con- 

 trol of the disease so far as onr present 

 knowledge and experience allow. 



Practical Knowledge Sought. 



Unfortunately, nothing is known con- 

 cerning the control of many diseases of 

 tae rose, and but little concerning even 

 some of the most common diseases; and 

 what little is known is mostly of an 

 academic rather than of a practical 

 nature and not accessible to the average 

 grower. Every grower who has en- 

 deavored to obtain much information 

 upon any rose disease has been brought 

 face to face with this unfortunate situa- 

 tion. It is for the correction of this 

 condition that members of the Ameri- 

 can Rose Society have enlisted the ser- 

 vices of a plant pathologist to investi- 

 gate rose diseases and place the in- 

 formation before the growers. 



The preliminary survey has shown 

 that the two most common diseases of 

 the rose are the powdery mildew and 

 the black spot, both on indoor and out- 

 door plants. These diseases have re- 

 ceived the most attention of growers 

 and plant pathologists in the past. It 

 has been proved beyond doubt that 

 they are caused by fungi, the lile-his- 

 tories of the casual organisms have been 

 partially worked out, and various sug- 

 gestions for control offered. Consid- 

 erable work remains to be done to de- 

 termine the conditions which favor the 

 development of these diseases and the 

 best methods of treatment. It is the 

 plan of the writer to publish a short 

 article in the near future upon each 



of these diseases, in which the known 

 facts concerning them will be placed 

 before the growers. 



However, the survey has revealed the 

 fact that other diseases besides mildew 

 and black spot cause rose growers con- 

 siderable losses. In fact, many green- 

 house men claim that these two diseases 

 cause them little worry. 



Root-Bot Observations. 



Ophelia and American Beauty plants 

 affected with a serious root — or crown 

 — rot have been received from growers 

 and observed by the writer, in visits to 

 rose houses. The plant decays just be- 

 low the surface of the soil, usually 

 where the plant breaks, the developing 

 branches being encircled by the rot. 

 Soon the parts of the plant above 

 ground become yellow and of a sickly 

 • appearance, as if starved for moisture 

 or food; and die a more or less linger- 

 ing death. Some growers have kindly 

 furnished samples of plants so affected, 

 and several organisms which may pos- 

 sibly be causing the disease have been 

 isolated from diseased tissue. Inocula- 

 tions will be made to determine which 

 organism is the cause. The life-history 

 of the pathogene will be studied and 

 an attempt made to work out some 

 method of control. This is necessarily 

 a slow process, but will, we trust, re- 

 sult in the discovery of an effective 

 means of controlling the trouble. 



Other diseases which have been noted 

 are: (1) crown gall, caused by a bac- 

 terial pathogene, affecting the roots and 



occasionally the stems of both indoor 

 and outdoor roses; (2) rhyllosticta 

 leaf -spot, affecting outdoor roses, chief- 

 ly ramblers; (3) other leaf-spots and 

 cane diseases of unknown causes. Work 

 upon the cause of the diseases in this 

 last group is now under way. Exten- 

 sive experiments on the control of leaf- 

 spot diseases of indoor and outdoor 

 roses are being planned and will be 

 tested out as quickly as possible. Re- 

 ports of progress will be made from 

 time to time. 



To Send Specimens. 



Some misunderstanding seems to exist 

 among growers in regard to sending 

 specimens for examination. Where de- 

 sirable a postal card will bring to the 

 grower one or more franked tags which 

 will carry specimens by mail postage 

 free; or the grower may pay the postage 

 if he so desires. The specimens will 

 be examined and the sender furnished 

 with all available information regard- 

 ing the cause and control of the disease. 

 Not only members of the American 

 Rose Society, but rose growers in gen- 

 eral, may take advantage of this op- 

 portunity to obtain information relat- 

 ing to rose troubles. By sending speci- 

 mens the grower will not only help him- 

 self, but will be materially aiding the 

 project. Specimens will always be ap- 

 preciated, regardless of whether or not 

 they are of a new or old disease, or of 

 economic importance. It is especially 

 desired at this time to obtain rose 

 plants affected with root diseases. 



Address all correspondence to L. M. 

 Massey, Department of Plant Pathology, 

 Cornell University, Ithaca, N. Y. 



OBTLLO'S GBEENHOUSES. 



The accompanying illustration shows 

 an establishment that is typical of the 

 greater number in this trade. It is that 

 of Nicholas Grille, at Mjlldale, Conn., 

 and was only recently completed. A 

 general stock is grown. 



North Judson, Ind. — C. Vorm, who 

 formerly was located at Hammond, has 

 removed to this place and is doing busi- 

 ness as the American Oak Preserving 

 Co. When the oak season is over it is 

 the plan to prepare other decorative 

 materials. 



New Establishment of Nicholas Grillo, at Milldale, Conn. 



