42 TRANSACTIONS OP THE ILLINOIS' 



THE GRAPE ROTS. 

 BY T. J. BURKILL. 



Among the host of parasitic fungi affecting our grape vines 

 there are four species which are specially injurious — two usually 

 called mildews, and two rots. The common names are, however, vari- 

 ously applied for those commonly known as mildews often cause the 

 decay of the berries when growing upon them, and are then spoken 

 of as rots, while the terms grey rot, brown rot, and black rot are now 

 used to designate the effect produced by one of these four species of 

 parasites, now another, again another. Practical cultivators do not 

 ordinarily care much what particular species of fungus injures their 

 crops, or whether it is a fungus or insect or anything else so long as 

 some one method may be used to prevent or cure the difficulty, yet 

 our success would be much more certain, and our accounts of experi- 

 ments far more valuable if such distinctions were carefully made. 

 In the case of these great pests, it is important to know which 

 one of the two mildews is the destructive agent in order to know 

 whether the application of sulphur will be of service or not. In 

 Europe long experience has taught the grape growers the value of 

 flowers of sulphur in destroying mildew, and he who would omit to 

 use the remedy would not be pitied if he lost the season's produce of 

 fruit. So, when men from the old world engage in horticulture 

 work with us, this sulphuring of the vine is one of the established and 

 necessary elements of culture in their opinion. In the same way 

 those who have never crossed the water gain in one way or another 

 the idea that sulphur destroys mildew, and so apply it as an orthodox 

 and essential procedure. Then some one with an observing turn of 

 mind finds that sulphuring does no good, and so reports the hetero- 

 dox opinion to a society where the subject gets variously discussed. 

 A knows that sulphur kills mildew; B knows it does not, andC, a be- 

 ginner in the art that doth mend nature, gets sadly mixed in his un- 

 derstanding. In Europe there has been until recently but one species 

 of fungus which showed itself as jnildew on the leaves, etc., of the 

 grape. In America, besides this one, or another very similar, a very 

 distinct species with widely different habit also occurs as the white 

 material called mildew. Sulphur is of no avail against the latter, 

 and as it, in the West at least, is much more prevalent one year with 

 another than the other species, sulphuring rarely does any good with 

 us. Yet the process goes on, and the instructions of the books are 

 too often followed by disappointment and loss, the latter both in 

 money and confidence. The species fought with sulphur in Europe 

 has long been known as Oid/nin Tuckeri ; ours of like character as 

 Uncinula Spiralis. It seems, however, pretty certain that both names 

 belong to the same species which, with us, reaches a second state of 

 development not yet observed in the old world. Whether one or 



