448 Report of the Department of Entomology of the 



The experiments which the Station has conducted have con- 

 clusively shown that the numbers of the psylla can be reduced 

 to insignificant proportions through the adoption of spraying practices 

 against the " flies " or the eggs. In most cooperative efforts orchard- 

 ists have been able by one thorough application of a spray made 

 against either of these stages to destroy a large part of the infesta- 

 tion, which has resulted in comparative freedom of the trees from the 

 insects during the remainder of the season. In cases of severe 

 infestations other pear-growers have found it advisable to make 

 sprayings for both the " flies " and the eggs. But through attention 

 to the habits of the psyllas and care on the part of the orchardists 

 in making the applications a single treatment has usually proven 

 sufficient for the control of the insect in either of these stages. 



The control of the pear psylla through spraying for the hibernating 

 adults and their eggs is accomplished with comparative ease in 

 isolated orchards or small plantings. In localities where orchards 

 adjoin or are somewhat closely situated the control of this 

 pest is usually attended with greater difficulties. Very often a 

 neglected plantation in the neighborhood of well-sprayed orchards 

 serves as a source of infestation. Such a situation provides 

 conditions under which individual orchardists may fail to secure 

 good results from spraying. This difficulty can best be overcome 

 by cooperation among the growers affected, who should act as a 

 unit in carrying out repressive and remedial measures. The chief 

 factors which make for efficient work against hibernating " flies " 

 and their eggs are (1) a knowledge on the part of the grower of the 

 habits of the " flies " and an acquaintance with the eggs; (2) an 

 understanding of the conditions under which these stages are most 

 vulnerable to sprays; (3) thorough work in spraying. 



METHODS OF TREATMENT. 



SPRAYING MIXTURES AND FORMULAS. 



Formula 1. Tobacco Extract. 



Tobacco extract (40 per ct. nicotine) f pt. 



Water 100 gals. 



Soap 3 to 5 lbs. 



Formula 2. Fish-oil Soap. 



Fish-oil soap 20 lbs. 



Water 100 gals. 



These are recommended for fall or spring spraying to destroy the 

 " flies." 



