140 STATE POMOLOGICAL SOCIETY. 



thoroughly iufested, those of the 1'. Inbrusca in the same row showed no traces 

 of the mildew ; but tea days later both kinds were equally affected, and up to 

 time of writing, September 12th, plants of 1'. cordifoUa var. rijjciria have still 

 escapctl. 



To consider further this point, let us give some of the experience of others. 

 "The fungus which we are now considering is very abundant on Yitis (Bstivalis, 

 Michx. ]'. Jahrusca and all their cultivated varieties; on Y. cordifoUa, on T". 

 vnljnna, and tlic cultivated Catawba grape, and in fact on nearly all varieties 

 of American grapes, althougli we have nut as yet heard of its occurring on the 

 Diana grape. It is probably found throughout the whole United States east 

 of the liocky Mountains, but it has not yet been reported from the west coast. 

 It has been said not to occur on the smooth-leaved species ; but its presence on 

 Y. cordifoUa proves the contrary. It has also been said that it does not occur 

 on the varieties of Y. vinifera growing in this country. As we have not had an 

 opportunity in this region of examining such varieties growing in the open 

 air we cannot controvert this point, but our experiments prove that it can be 

 made to grow on Y. vinifera, and oven more luxuriantly than on American 

 species.''* 



Among the letters received, one from Michigan says: "The Croton was the 

 only variety much affected last year. * * * I do not think I gathered 

 a single perfect bunch; almost the entire crop of this variety was ruined. My 

 Delawares did not seem to be affected to any jDerceptible extent." 



Another party from Indiana tells us "The varieties most affected with us are 

 thin leaved varieties, such as Ilogers' Hybrids, lona, and Diana. Such heavy 

 leaved varieties as Ives' Seedling, Concord, and llartford are scarcely ever 

 affected unless the weather is so bad as to totally destroy other kinds." 



From Ohio comes word that "The Peronospora mildew is more prevalent on 

 varieties from American stock, and the surface mildew or 'Oidium' prefers the 

 European, though under favorable circumstances both may be found on all." 



A 5lassa<;husetts grape grower, among other items, sends the following; "'I 

 grow in quantity only the Concord, whicii shows an average mildew amounting 

 to considerable less than one per cent in depreciation of the crop. The max- 

 imum never being more than two to three per cent. Other varieties are much 

 more prone to mildew, and one that I believe never failed so long as I grew it 

 (until three years ago), was Rogers' No, 15 (Agawam)." 



Let us look at the description of the fungus. "The date of its first aj)pearance 

 with us has always been from the 10th to the 15th of July. It appears as a shin- 

 ing mouldiness upon the peduncle of the berry and extending from its insertion 

 over the berry more or less. It occurs first near the ground, that is, the lower 

 clusters, more especially if densely shaded." This is evidently the Oidium. 

 Further conlirmation was received a short time ago in the shape of the mildew 

 itself. Tlie writer distinguishes the two kinds of mildew, because in the same 

 letter, after speaking of the Concord, he says: "Some of the other varieties 

 are somewhat prone to a form of mildew which is developed not on the berries 

 but exclusively upon the leaves. The Delaware, Croton, and some others are 

 quite liable to it." This is evidently our subject, but it also grows in the ber- 

 ries, as figures, showing the thread and "suckers" in the grape tissue, was 

 drawn from a section through a Concord berry kindly sent by this gentleman. 

 These berries affected by the Peronos})ora are covered by no mouldiness, but 



*Dr. Farlow oa American Grape Milde\v, ia Busscy UuUetin, Vol. I., pp. 421, 42"2. 



