New York Agricultural Experiment Station. 943 



or to destroy the eggs and young larvae of the first brood while they 

 are still on the branches, stems and fruit spurs or on the unopened 

 cluster buds. 



The first treatment is usually the best one to adopt as it so reduces 

 the number of hibernating flies that few eggs are laid the next spring. 

 Then, if lime-sulphur is to be used in the spring for scale, as is the 

 common practice in many large orchards, its application can be 

 postponed a little and the few psylla eggs that are laid be destroyed. 



Especial pains should be taken to destroy 

 Spraying the pest in this stage, as effective work greatly 



winter flies. reduces the number of eggs deposited on the 

 trees and simplifies subsequent spraying opera- 

 tions. The best means of killing the " flies " is spraying during 

 a period of warm weather, preferably in November or December, 

 or during March or early April. A rise in temperature 

 induces the insects to emerge from their hiding quarters 

 and creep to the portions of the trees exposed to the 

 warm rays of the sun and protected from a cold wind. 

 While the insects are able to crawl they are very sluggish 

 in their movements and do not fly. This habit makes 

 them very vulnerable to treatment and the grower 

 should take full advantage of it by so spraying that 

 YigT^—con- none of the insects be allowed to escape. To kill 

 dition of the flies it is essential to wet thoroughly all portions 

 durfnT the of the trees, and especial pains should be taken to 

 the ay ^iiJ°" force the liquid under loose bark and into all cracks 

 and crevices in the bark. The experiments by this 

 Station have also shown the wisdom of spraying one tree 

 thoroughly before proceeding to another. In balmy weather 

 the flies, like squirrels, may dodge quickly to the opposite side of 

 the tree. By spraying the entire tree they are unable to avoid 

 wetting by the spraying mixture. Treatment late in the fall or 

 early winter is especially recommended as the influence of steadily 

 decreasing temperatures at this season on the movements of the 

 flies makes them especially vulnerable to spraying. In planning for 

 this work select days when there is no danger of the spraying mix- 

 ture freezing on the trees. The most satisfactory spray from the 

 standpoints of safety to fruit and leaf buds and effectiveness against 

 the insect is three-fourths of a pint of tobacco extract to one hundred 

 gallons of water to which are added from three to five pounds of 

 dissolved soap. (Formula 1.) It is also advisable to remove the 

 loose and rough bark to discourage the flies from wintering on the 

 trees and to render them more exposed to spraying mixtures. This 

 operation may be done at a convenient time but the bark is more 

 easily detached following a wet period. To avoid infection with 

 disease care should be taken not to cut into live tissues. 



