i68 Bulletin 235. 



II. FINAL DEMONSTRATION OF THE EFFICIENCY OF A 

 POISON SPRAY FOR CONTROLLING THE GRAPE 



ROOT-WORM 



During the past four years I have made extensive investigations on 

 the insect pests of the grape in the vineyards of the Chautauqua grape 

 belt. Each year the grape root-worm has received a large share of at- 

 tention and success has crowned the efforts made to find a practicable 

 and effective method for controlling it. 



As the adult insects or beetles feed quite extensively on the grape 

 foliage, theoretically th^^ should succumb to a poison spray. Under my 

 direction extensive experiments have been made in several vineyards with 

 a poison spray each year since 1902, and other vineyardists have also 

 cooperated in such experiments in their own vineyards. The results up 

 to the present year have been recorded in Bulletins Nos. 208 and 224. In 

 1903 and 1904 the results were very striking and effective, but it was de- 

 cided to make a further and final test of the poison spray method in 1905 

 in the same large vineyard that was sprayed the previous year. The vine- 

 yard was found to be considerably infested, as from 15 to 40 grubs and 

 pupse could be easily found in the soil near each vine examined. 



Mr. R. S. Woglum, an expert student assistant, was placed in charge 

 of the experiment, and the first application was made July 3rd. The 

 spraying was done with a Niagara carbonic-acid gas sprayer, and arsen- 

 ate of lead (Disparene) was used at the rate of 8 pounds in 100 gallons 

 of water. One cylinder of the compressed carbonic-acid gas furnished 

 sufficient power to throw out 500 gallons of this spray under a pressure 

 of 80 pounds, thus making a very fine spray from each of the 8 nozzles. 

 The machine in operation is shown in Fig. 43. A second application of 

 the same spray was made on July 13th. It required 900 gallons of the 

 mixture at each application on about 8^4 acres. The total expense was 

 about $3.25 an acre for each spraying. 



The results were equally as satisfactory as those obtained in the 

 previous years' work. On July loth, I carefully examined 15 vines in 

 different sections of the vineyard for eggs of the root-worm beetles. On 

 the first 5 vines I found no eggs ; on 5 other vines near the center of the 

 vineyard, 2 egg-clu.sters were found : and on 5 vines in one corner, 17 

 egg-clusters were found; the 15 vines thus yielding only 19 egg-clusters. 

 In another infested vineyard which has been well cared for but was not 

 sprayed, I found 11 egg-clusters on the first vine examined at random. 



