444 Report of the Department of Entomology of the 



the eggs had hatched. A few nymphs hatched on sprayed trees 

 but the infestation was slight, and was not sufficient to affect appre- 

 ciably foliage, yield of pears, or development of the buds for the 

 next year's crop of fruit. The percentage of eggs destroyed by 

 the treatment is given in Table XI. 



Experiment No. 8. — During the week of May 2, 1911, 400 Kieffer 

 pear trees were sprayed with the homemade concentrated lime- 

 sulphur solution, 26° B., at a dilution of one gallon of the concentrate 

 to six gallons of water. At this time the cluster buds were separating 

 at the tips and the young leaves were unrolling. In making the 

 application care was used to coat thoroughly, with the spray, the 

 bud spurs and smaller limbs and especially the under sides of the 

 branches, for in these situations the eggs were largely deposited. 

 Some eggs were laid on the trees after the spraying was accomplished 

 and late appearing " flies " continued to oviposit on the trees despite 

 the application of the lime-sulphur wash. 



Results on eggs. — The destructive effects of the concentrated 

 lime-sulphur solution on psylla eggs was most strikingly demon- 

 strated in this orchard. Collapsed and discolored eggs were abundant 

 on all the trees within a short time after the spraying operations 

 were completed. Eggs deposited on bud spurs after the trees were 

 sprayed hatched and were apparently not affected by the wash 

 which was upon the trees. The percentage of the eggs destroyed 

 by the treatment in this orchard is given in Table XL 



Effects on cluster buds and foliage. — There was a slight amount of 

 burning on young leaves and fruit stems wherever sediment was used 

 in the lime-sulphur, which resulted in the dropping of occasional 

 young blossom stems. The fruit clusters set full and in June there 

 was no noticeable reduction in the numbers of the maturing pears 

 on the sprayed trees. Applications of the clear solution did not 

 harm the fruit clusters and caused only a slight discoloration of the 

 tips of the leaves. No harmful effects to the trees resulted from 

 these injuries to the young foliage, which made a luxuriant growth, 

 and the trees developed plenty of blossom buds for the following 

 year's crop of fruit. 



Experiment No. 4- — A block of about 300 Kieffer pear trees 

 received an application of commercial concentrated lime-sulphur 

 solution, 32° B., in the proportion of one gallon of the concentrate 

 to eight gallons of water. The trees were plentifully stocked with 



