MARCH 2!i. iswn. 



The Weekly Florists' Review. 



507 



Decorations of the Casket containing the remains of the late W. W. Greene, Watertowr, N. Y. 



and has long been known to the rose 

 growers of Europe. The foliage, when 

 attacked, soon develops the character- 

 istic black spots, and the leaves be- 

 come elsewhere pale and shortly fall 

 to the ground. As a result, rose houses 

 badly infested with the black spot 

 show but few leaves and fewer blooms. 

 The microscopic structure of this 

 fungus has been fully considered, with 

 plates, in the first annual report made 

 by Prof. Scribner as Chief of the Sec- 

 tion of Vegetable Pathology of the 

 United States Department of Agricul- 

 ture for the year 1S87. It only needs 

 to be said here that experiments with 

 this fungus have been carried on suf- 

 ficiently by the New Jersey Station to 

 warrant the assumption that it can 

 be controlled by the proper use of 

 fungicides. This trouble may be held 

 in check by the carbonate of copper 

 compound (cupram), using five ounces 

 of the carbonate of copper to three 

 quarts of ammonia and sixty gallons 

 of water. The spraying should be 

 done once a week, using a hose with 

 a nozzle that gives a fine spray. The 

 point should be to wet every part ot 

 the plant, and yet not drench it. If 

 man^ leaves have fallen from the 

 plants they should be gathered up and 

 burned. 



Some varieties are more liable to 

 the black spot than others. When 

 possible — that is. when all other things 

 remain the same — it is, of course, wise 

 to grow those least susceptible to the 

 disease. It may be said, in passing, 

 that during the year 1S92 the Black 



Spot was observed by the speaker 

 upon a species of wild rose (Rosa hu- 

 milis). where it was causing the leaves 

 to become spotted and yellow. It is 

 not surprising, for the wild plant was 

 growing but a short distance from a 

 neglected estate where garden roses 

 were badly spotted. 



The actinonema is a small genus 

 and some of the species are parasites 

 upon the basswood, beech, ash, vi- 

 burnr.m. The one upon the rose is 

 not found upon plants outside of the 

 genus rosa, and there has its favor- 

 ite species and varieties. This is 

 shown in a remarkable manner with 

 some of the cultivated sorts grown 

 "side by side in the same house. It is 

 often very bail upon the "American 

 Beauty." 



The Rose Leaf Blight. 

 (Sphnerella rosigena Kit) 



A fungus that disfigures and injures 

 the rose leaves almost as badly as the 

 Black Spot is the Sphaerella rosigena 

 Ell., and commonly called the Rose 

 Leaf Blight. A thoroughly diseased 

 leaflet has large irregular blotches of 

 gray color surrounded by a margin of 

 dark purple. The gray dead center 

 of the spot bears a number of pimples 

 or specks — more numerous and con- 

 spicuous near the center, and in these 

 the spores are produced. 



Under the microscope the fungus is 

 very different from the Black Spot, 

 and instead is closely related to the 

 leaf blight of the strawberry, which 

 is due to Sphaerella fragariae Tul. In 



other words, the two blights in ques- 

 tion are as closely related as any two 

 species of the genus rosa. It is im- 

 portant to know these relationships 

 between the various plant diseases, 

 for it is helpful in the struggle in 

 overcoming them. The Leaf Blight of 

 the strawberry is very much more 

 common than that of the rose and any 

 effective remedy found for the former 

 may be of value in checking the rav- 

 ages of the latter. Fruit growers have 

 found this strawberry Leaf Blight a 

 hard one to check, perhaps because of 

 its many forms of spores and the low 

 habit of the plant and the consequent 

 difliculty of readily spraying the foli- 

 age upon the under side. This diffi- 

 culty does not obtain with the rose, 

 and it may be controlled more easily. 

 There is no question but that the 

 standard fungicides should be used 

 when this fungus i.s at work. 



The Black Rot of the grape, due to 

 Laesttadia Bidwellii (Ellis), is a first 

 cousin to the rose disease in hand, and 

 the fact is mentioned because the 

 grape rot trouble is one of the most 

 common and destructive of the whole 

 list of fungous diseases. There is a 

 stubbornness met with in attempts to 

 control this decay that almost baf- 

 fles wine growers, especially during 

 moist months in the growing season. 



The Rose Mildew. 



(Sphaerothera pannosa Wallr.) 



The most familiar fungous enemy of 

 the rose is the mildew (Sphaerotheca 

 pannosa Wallr.). This disease has 



