88 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



gradually disappear as a pest; but frequently the following season will 

 favor the growth and development of vast numbers of hoppers, which 

 the grower is generally unprepared to combat. 



During the seasons of 1920 and 1921 the hoppers have caused great 

 damage to hundreds of acres of grapes in this section, and naturally 

 the areas most severely attacked were those closely approximating 

 woodlands. The serious damage caused by these pests can be realized 

 more fully when it is known that foliage severely attacked dried pre- 

 maturely and curled up before the grapes had ripened. Consequently 

 many growers were refused markets for their grapes in 1920 at the 

 Welch grape juice plant on account of the red appearance and sour flavor 

 of the partially ripened fruit. 



Many of the growers with a large acreage of grapes were totally un- 

 prepared to spray when the nymphs appeared in great abundance, and 

 the leaves began to turn yellow. One of the most progressive growers 

 stated that he had neither sufficient length of time, nor enough men to 

 spray with the customary trailer nozzles, and that if he attempted to do 

 so other fruits must go unsprayed. Furthermore, a large percentage of 

 the hoppers would become adults by the time the spray could be applied. 



For many years attempts to combat the Grape Leaf hopper and Grape 

 Berry moth with the customary "set nozzles" have been made with 

 varying success. In the old type of sprayer the nozzles are so arranged 

 that the halves of two rows are sprayed simultaneously, thereby per- 

 mitting the hoppers to escape from the row by way of the unsprayed 

 portion, many of them flying to safety before the spray. In this type 

 the nozzles were set horizontally to the vine on vertical rods at either 

 side of the tank. This arrangement of nozzles had a tendency to push 

 the leaves downward instead of exposing and treating the under surface 

 where the hoppers usually feed. 



The boom system with the arrangement of nozzles for spraying one 

 row at a time from both sides and above has been previously used but 

 the nozzles in that case were placed horizontally to the vine and machines 

 were being delivered to the growers in that condition in 1921. Further- 

 more the lower nozzle was two or three feet above the ground when the 

 spray was applied and the nozzles were all set in the same plane. In 

 view of the unsatisfactory results obtained from this type of set nozzle 

 a rearrangement of nozzles w^as devised which has given very satisfactory 

 results. This arrangement permitted the operator to be seated on the 

 spray tank holding a f inch horizontal pipe about seven feet long, con- 

 nected with the spray tank and extending over the top of the row. From 

 this horizontal piece of pipe a three foot pipe connected by three feet 

 of rubber hose extended vertically almost to the ground on either side 

 of the row at a distance of about three and one-half feet apart. 



