446 Report of the Department of Entomology of the 



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

 of unopened leaves occurred which caused no noticeable ill effects 

 to the trees or fruit. The trees blossomed full and developed a 

 luxuriant growth of foliage. In midsummer the leaves were green 

 and the fruit buds were strong and gave promise of an excellent 

 crop during the following season. The crop of fruit which set was 

 large and the pears were clean, of excellent size and free from the 

 gummy, blackened appearance which ordinarily accompanies the 

 work of the psylla on pear trees. 



During the spring of 1911 cooperative spraying experiments for 

 the control of the psylla in the egg stage were conducted in twenty- 

 five pear orchards. In these experiments lime-sulphur solution 

 was the only spray applied since this had proven the most efficient 

 of all the materials used in the previous tests on psylla eggs. Appli- 

 cations of the mixture in the different orchards were made during 

 the last week in April or the first week in May, as the cluster buds 

 were separating at the tips. The results bore out the promises of 

 the earlier tests and in the majority of the orchards all of the eggs, 

 so far as could be determined, were destroyed. In occasional 

 plantings where lack of care was exercised in making the applica- 

 tions of the lime-sulphur a small percentage of the eggs hatched 

 and summer treatments were made to protect the pear trees from 

 injuries by the summer broods. Pear-growers who sprayed care- 

 fully were highly pleased with the results obtained from the work 

 and these orchardists have come to depend on the lime-sulphur 

 solution for psylla control in their pear plantings. Other fruit- 

 growers who are each year required to spray for the psylla have 

 adopted this means of control for the insects; and these men, 

 through careful spraying and attention to the egg-laying habits, 

 and to the development of the buds, have secured results which 

 have given them much satisfaction. Pear-growers generally are 

 able through this single spraying for the eggs to protect their 

 crops of pears from the work of the insect during the growing 

 season and insure a good development of the succeeding year's 

 fruit buds. 



Tests with other spraying mixtures. — A number of experiments 

 to test the effects of other insecticides in comparison with lime- 

 sulphur were made during the spring of 1910. The additional 

 materials were kerosene emulsion, fish-oil soap, and nicotine prepara- 



