336 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION. 



Methods of Treatment. Since sulfuring the vines for the treatment of 

 oidium has become general in France, there has been little trouble with 

 erinose. The mite seems as sensitive to the fumes of sulfur as the red 

 spider, and several sulfurings during the late spring and early summer 

 are recommended for the control of the mite. The only vineyards which 

 have been found badly affected in California are those in which little or no 

 sulfuring has been done, or those where the growth of foliage has been 

 so luxuriant as to prevent the evaporation of the sulfur by the sun. 

 In the latter cases the vines are so strong that they practically 

 receive no harm from the disease. Tests made on Tokay vines indicate 

 that the erinose can be easily and readily controlled at any stage in 

 California by sulfuring. In severe cases a winter treatment of the vine 

 stumps is practiced in France. This treatment consists in pouring 

 about one quart of boiling water over the stump. For very large 

 stumps a somewhat greater amount of water is used, and for smaller, 

 vines a proportionate amount. This method is said to be very efficacious, 

 and with the portable boiler constructed for the purpose two men can 

 treat from fifteen hundred to two thousand vines per day. Cuttings 

 taken from affected vines for the purpose of rooting or grafting may be 

 thoroughly disinfected by placing them in hot water (122 F.) for ten 

 minutes. If this is done carefully all the mites and their eggs will be 

 destroyed without injury to the cuttings. 



NEMATODE ROOT GALL. 



(Heterodera radicola (Greef) Mull.) 



Nematodes are not insects, nor are they very closely related to 

 insects. They belong to the class of animals known as Vermes or true 

 worms. The common earthworm is the best known example of the 

 class, although it occupies a position in the group higher than that of 

 the nematodes. There are a good many species of nematodes some 

 living in the ground, a good many are parasites on animals, and a few 

 live parasitically on plants. Often in moist soil, rich in humus, such as 

 vegetable gardens, there may be large numbers of very minute whitish 

 transparent worms. These are nematodes, however, that do no notice- 

 able injury to plants, and it is only the parasitic species, of which the 

 subject of this account is an example, that are of any concern to growers 

 of crops. 



The species of nematode worm that attacks the grapevine in this 

 State according to Dr. Ernst Bessey of the Department of Agricul- 

 ture, who is at present engaged in an investigation of this group is 

 Heterodera radicola (Greef) Mull. This species is widely distributed 



