New Yokk Agricultural Experiment Station. 445 



eggs which had been deposited, for the most part, on the under 

 side of the twigs and smaller branches. The spray was applied 

 during the week of May 2, 1911, at the time when the cluster buds 

 were just beginning to break apart at the tips. The trees were 

 thoroughly drenched with the spray and care was exercised to cover 

 the under sides of the limbs. 



Results on eggs. — Few eggs survived the action of the spray. 

 Some nymphs were found on the opening buds but the trees, for 

 the most part, were free from the young insects. The natural 

 increase of psyllas which hatched from eggs not destroyed by the 

 spray was slow and the resulting infestation was inconsiderable. 

 On unsprayed pears an abundance of nymphs hatched from the eggs 

 and the trees were wet with honey dew during the remainder of 

 the growing season. 



Effects on cluster buds and foliage. — A slight blackening of the 

 tips of the young leaves occurred which was of small importance. 

 No noticeable injuries resulted to the blossom petioles, and young 

 fruits were numerous. The foliage was healthy during the summer 

 and fruit buds developed in goodly numbers. The crop of pears 

 was not large on treated or untreated plats, which was due primarily 

 to the failure of the trees to form fruit buds during the previous 

 year owning to their weakened conditions from earlier psylla 

 attacks. 



Experiment No. 5. — In this experiment 2400 Angouleme pears 

 were sprayed with lime-sulphur solution, 32° B., at a dilution 

 of 1-8. Eggs were very abundant on the trees and the deposition 

 had practically ceased when the spraying operations commenced. 

 The applications were made during the period of April 25-28 at 

 which time the blossom clusters were beginning to separate. The 

 small size of the trees permitted a most thorough coating of the 

 limbs and smaller branches with the spray. 



Results on eggs.— The treatment resulted in an almost total 

 destruction of the eggs. Owing to their protected situations a 

 small percentage of the eggs which were not hit by the spray hatched 

 and occasional nymphs appeared on the blossom clusters. These 

 larvae did not increase in numbers and the few infested fruit spurs 

 were subsequently removed before the nymphal instars were com- 

 pleted and the summer brood of " flies " emerged. In August 

 this planting was quite free from psyllas. 



