STATE HORTICULTURAL SOCIETY. 43 



two, the growth is the same, and always confined to the surface of 

 the leaves, young shoots and berries; /. e. the growing threads never 

 penetrate the tissues. This mildew, then, is always accessible to a de- 

 structive agent finely dusted over the vine; but the case is wholly dif- 

 ferent with the species known as PrroHosponi rif/i-ohi. the most com- 

 mon one with us. This grows thiough and through the inner tissues 

 of the soft i)arts of the vine, and only sends out its fruiting threads 

 or stems: there is. therefore, no such thing as reaching it with a 

 something externally applied. Some one proposes to stir the sulphur 

 into the soil that it may be taken up by the roots and sent up through 

 the plant — a bright idea, l)ut unfortunately, evolved without proper 

 knowledge of vegetal)le ])hilos()phy. 



Botii of these fungi affect all the green parts of the vine, stems, 

 leaves, tendrils, peduncles and fruit. Both show themselves as 

 minute, white, mealy or cobweljby growths. But they are readily 

 enough distinguished. On the leaves — -where ])rincipally (dj- 

 served — the surface grower is almost entirely confined to the upper 

 side; the inside worker sends its fruit-stems out beneath. The latter 

 are usuallv clustered in spots, the former are more evenly spread over 

 the surface. In the case of the fruit the inside grower may l>e best 

 determined by the purplish-red tint, like a blush^ which appears on 

 the unripe berries. The color is a suffused tint without definite 

 border, and when once recognized can afterwards be readily known. 



Under the microscope the characteristics of the two species are 

 very distinct, so that the merest tyro with the instrument should be 

 able to recognize the form present; but these characteristics need not 

 be given here. When there is any doul)t a])out the matter everyone 

 probiilily knows some one who is familiar with microscopic work and 

 may appeal to him. In fault of other means send specimens to the 

 President or Secretary of this Society, and if he cannot directly 

 answer it, it will be good for him to find out how to distinguish the 

 parasites, after which he can reply. 



The two " rots " are different from the mildews in the fact that 

 thev (the rots) never show anything of the white, mealy, or powdery 

 or cobwebby material which gains the name of niclil-fliaa, •" meal- 

 deAv" or " mildew." As both of the mildews, however, cause the 

 fruit to cease growth, and to finally die and decompose, attention to 

 the berries alone might lead one to incorrect conclusions about the 

 cause. The rots are especiallv to be distinguished by causing well- 

 defined areas of the berry to change color, and in other ways to in- 

 dicate the effects of the parasite in such area, while other parts of 

 the berrv retains the appearance of health and soundness. The sep- 

 arating line ])etween the diseased and hcallliy jjarts is very i)ercei)ti- 

 ble, though the affected spot gradually enlarges and may finally in- 

 clude the whole fruit. When the death of the berry is caused l>y 

 the mildew parasites no such plain boundary of the affected parts is 

 to be seen. 



