138 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



if the soil is known to be infested, disinfection is sometimes practiced 

 before planting out young vines. This is done by an application of 

 carbon bisulfid to the soil. Trap plants have also been used, these being 

 annuals that are pulled up before the nematodes escape. In time it 

 may be found that resistant stock is the solution of the problem. In 

 the bulletin already referred to it is stated that the Isabella is slightly 

 resistant, while Vitis riparia has shown no nodules after the first year. 

 This fact is interesting as a suggestion that both phylloxera and 

 nematodes may be controlled by the same resistant. 



