440 Report of the Department of Entomology of the 



few " flies " emerged and no further applications of sprays were 

 needed to check the operations of the psylla that season. Fall 

 spraying for psylla adults has been repeated in this planting each 

 year since 1911 and is relied on entirely by the owner for the pro- 

 tection of the pear orchard from the pests. 



On the basis of the above results a number of experiments along 

 the same lines have been conducted in succeeding years in coopera- 

 tion with fruit growers. In the main, these later efforts have 

 corroborated the results of the initial tests. Large percentages 

 of the " flies " were invariably destroyed by careful spraying and 

 in isolated orchards, particularly, the work of combating the insect 

 by spring and summer spraying was very much simplified and in 

 some instances was rendered entirely unnecessary. In occasional 

 plantings, because of difficulties due to inclement weather or because 

 of adjoining orchards, these treatments afforded only partial relief 

 and in such cases it was necessary to resort to the usual sprayings 

 the following spring. In none of these tests were miscible or home- 

 made oils applied for fear of damage to the trees. Of the mixtures 

 employed, tobacco extract, soap, and lime-sulphur with tobacco, 

 the tobacco extract (40 per ct. nicotine) has given the most satis- 

 factory results from the standpoints of safeness to the trees and 

 effectiveness against the insects. Applications of soap by a number 

 of growers have given very satisfactory results and have proven 

 somewhat less expensive than the tobacco preparations. 



SPRING SPRAYING AGAINST HIBERNATING ADULTS. 



During the later days of March, 1910, psylla " flies " appeared 

 in unusual numbers on trees in the orchard of the Collamer Bros, 

 at Hilton. At our suggestion a portion of this planting, comprising 

 about 1530 Bartlett, Kieffer, and Seckel pears of twenty years of 

 age, was sprayed with either kerosene emulsion at the rate of one 

 part of the emulsion to twelve parts of water, or with fish-oil soap 

 in the proportion of one pound of the soap to eight gallons of the 

 water. Applications of these sprays were made during the period 

 of March 21-26 at which time the psylla adults were quite active 

 and had spread over the trees. 



The application of the kerosene emulsion did not appreciably 

 lessen the numbers of adults as compared with those on adjoining 

 unsprayed blocks of pears, where there were myriads of the " flies " 



