INSECTS INJURIOUS TO THE GRAPE 497 



the fruit, two applications, one after vintage and the other just 

 before blossoming, giving the best results. It is applied by 

 pouring one-half to three-quarters ounce into holes a foot deep, 

 from IS to 24 inches apart, all over the vineyard, but not nearer 

 than one foot to the vine. The holes may be made with an iron 

 rod or dibble and are closed by packing the soil down with the 

 foot as soon as the liquid is poured in. Where extensively used 

 special injectors are used. Where the vines are much weakened 

 they do not withstand the effect of the bisulfide, and treated 

 vines must be thoroughly fertilized and cultivated; 



One of the best methods of destroying the root-lice where 

 water is available is by submersion. In California the best results 

 are secured by flooding with at least six inches of water for a 

 week or ten days as soon as the vines have ceased active growth 

 in November. A little later two to three weeks' submersion will 

 be necessary and in winter thirty-five to forty days. Flooding 

 for a couple of days in midsummer seems to destroy some, pf the 

 insects, but its main value is in stimulating a vigorous growth 

 of new rootlets. Longer flooding in summer, when., the aphides 

 might be most easily destroyed, injures the vines. 



On very sandy soils vines are uninjured by the phylloxera. All 

 sandy soils are unfavorable to the pes1t*and vines on tlfem die 

 more slowly, but to secure complete immunity there must be at 

 least 60 per cent of siliceous sand. Sands containing clay or 



which form lumps offer less resistance. 

 '. '*.,*, 



The Grapevine Root-borer * 



The larvae of the Grapevine Root-borer feed in the old roots at 

 some little distance from the base of the vine, and as there are 

 no indications of the pest, its presence may easily pass unnoticed. 

 Although not genera' ly recognized as a serious one it has been 

 known as a pest of the grape for fifty years, and has been observed 

 to do considerable damage in Kentucky and West Virginia. 



* Memythrus polistiformis Harris. Family Sesiida. See Fred E. Brooks, 

 Bulletin 110, W. Va. Agr. Exp. Sta. 



