1919 



ENTOMOLOGICAL SOCIETY. 



89 



Artificial Contiwl. 



The fact that a combination of the delayed dormant spray of lime sulphur 

 and the post blossom application of nicotine extract will control the psylla was 

 demonstrated this year in a twelve-acre orchard of Bartlett, Duchess, Anjou and 

 Flemish Beauty pears near Beamsville. This orchard had been subject to serious 

 })sylla injury for a number of years and last year it was very heavily infested. 

 This spring myriads of hibernating adults were found in it on the twigs and 

 branches and a very large deposition of eggs was made. 



The dormant spray of lime sulphur (winter strength) was delayed until 

 shortly before the blossoms opened (Eig. 21) and it was then applied with great 

 thoroughness, care being taken to coat every part of the tree. At this stage, the 



Fij 



Fig. 21. — Sliowins stage of fruit 

 bud development at the time 

 of "first application. 



22. — Blossoms fallen; time of second 

 application. 



vast majority of the eggs had been deposited and many of the earliest laid eggs 

 had hatched. After the blossoms fell (Eig. 22), the trees were again thoroughly 

 sprayed with lime sulphur and arsenate of lead (for scab and codling worm) and 

 Black Leaf 40, % P^- to 80 gals, of spray mixture, the latter of course being 

 added to destroy the psylla nymphs. At this stage an odd winter adult and a very 

 few belated eggs were still present on the trees. 



Besults: About two weeks after the delayed dormant spray was applied, an 

 examination of the orchard was made and it was observed that although the vast 

 bulk of the eggs and recently hatched nymphs had been destroyed, too many 

 nymphs were still present. In other words, we found that the spray for the eggs 

 would not by itself give us satisfactory control. The orchard was frequently 

 inspected after the post blossom application and up to the time the Elemish 

 ]^eauty pears were picked the trees were found to be practically free of psylla. 

 Early in July, we examined trees situated in different parts of the orchard and 

 on as much of the tree as could be conveniently looked over, we found from two 



