134 Bulletin 224. 



One hundrod and fifty-ono ego;-cliisters were found on 15 unsprayed 

 vines. 



Eleven egg-clusters were found on 15 vines sprayed twice with 

 arsenate of lead. 



Seven egg-clusters w^ere found on 15 vines sprayed twice with the 

 poison in Bordeaux mixture. 



These results are equally as striking as those we obtained in 1903. 

 Instead of an average of over 10 egg-clusters of the root- worm beetles 

 on each vine, the poison spray reduced the number to about one-half 

 f,n egg-cluster to a vine. And furthermore, it was also noted that the 

 egg-clusters on the sprayed vines were only about one-half as large as 

 those on the untreated vines; the average number in each cluster on 

 the former was about 15 and on the latter over 30, thus further cor- 

 roborating the previous season's work. Where no eggs are laid there 

 surely can be no grubs to eat the roots and kill the vines. It is rarely 

 that such remarkably favorable results are obtained with insecticides 

 in experiments against any injurious insect. We believe our results 

 are decisive and conclusive, and we consider it demonstrated that the 

 grape root-icorm can he effectively fought and controlled with a poison 

 spray. 



In all of our experiments against the root -worm, we have used the 

 arsenate of lead or "Disparene" poison, because it sticks well and 

 can be used much stronger than the other poisons without danger of 

 injuring the vines. However, it is probable that very effective work 

 can be done against the beetles with Paris green (1 lb. in 50 gals.) or 

 arsenite of soda or lime (1 lb. of the white arsenic in 100 gals.) 

 when used with Bordeaux mixture; if used alone in water these 

 poisons might burn the foliage severely. We recommend the use of 

 four pounds of the arsenate of lead or "Disparene" in 50 gallons of 

 water or Bordeaux mixture. Make two very thorough applications 

 of this poison, the first as soon as the first beetles are seen in the 

 vineyard, or about June 20 to 25, and the second a week or 10 days 

 later. These applications will reach the grape berry-moth (as 

 described in Bulletin 223), and if Bordeaux mixture is used, the 

 fungous diseases also will be checked. For the root-worm beetles the 

 spray should be aimed at the upper surfaces of the leaves, for there 

 is where the beetles feed, and the more thoroughly every leaf is 

 covered with a fog-like spray of poison, the more effective it will be. 

 We doubt if the grape root-worm can he so cheaply and effectively fought 

 and controlled hy any othei' method. 



In further confirmation of the above conclusions, it is a pleasure to 

 quote the following from a letter received last August from a promi- 

 nent vineyardist in the infested region: 



