942 Popular Editions of Station Bulletins of the 



In lime-sulphur solution, however, a spray seems to have been 

 found both efficient and safe. 



In 1910 and 1911 five careful tests were made by the Station in 

 pear orchards near Lockport and Medina, using either the home- 

 made or concentrated lime-sulphur sprays. Both forms of the 

 mixture proved destructive to the eggs or so weakened or repelled 

 the minute nymphs that did hatch that few of them reached the 

 young leaves. Other insecticides used had little or no effect on eggs 

 or young larvse and could not be counted on to control the pest. 

 The results of these tests are summarized in Table I. 



Table I. — Effect of Various Insecticides on Psylla Eggs. 



Treatment. 



Lime-sulphur 



Lime-sulphur 



Lime-sulphur 



Fish-oil soap 



Kerosene emulsion 



Miscible oil 



Black leaf extract . 



Black leaf 40 



Checks 



Dilution of spray. 



(Concentrate 1-8) . . 

 (Concentrate 1-6) . . 

 (Formula 15-20-50) 



(1-5) 



d-8) 



(1-15) 



(1-30) 



(1-40) 



(1-1000) 



Unsprayed 



Bud 



spurs 

 counted, 



90 

 75 

 102 

 100 

 100 

 100 

 100 

 100 

 100 

 100 



Eggs Counted. 



Sound. 



39 

 18 



1,806 

 232 

 900 

 800 

 824 

 920 

 810 



2,522 



Col- 

 lapsed. 



2,082 



339 



564 



20 



52 



45 



64 



48 



61 



175 



Eggs 

 killed. 



Per ct. 



98 



94 



*24 



8 



5.6 

 5.8 

 ' 7.2 

 5 

 7 

 7 



I 



* The small percentage of eggs destroyed in this test was presumably due to the 

 lower amount of sulphur in solution in the wash. 



Cooperative tests in twenty-five other orchards were made in 1911, 

 using lime-sulphur only as this had proved most effective in the 

 preliminary tests. In all cases where care was used to make the 

 treatments thorough and to apply the solution at the right time, 

 practically all of the eggs were destroyed. The owners who were 

 careful were highly pleased with the results of their work and have 

 come to depend almost entirely on this method for controlling the 

 psylla. 



To secure these good results it is essential to watch closely the 

 development of the pear buds and spray just when the cluster buds 

 are opening at the tips. 



Thus the problem of psylla control is reduced 



Conclusions. to a comparatively simple one — to make a 



thorough " clean-up " of the adult " flies " just 



before they enter or just before they emerge from winter hibernation, 



