192 



APPLIED ENTOMOLOGY 



The apple leafhoppers winter as the adults under rubbish and in spring 

 after mating the eggs are laid in the veins of the leaves. Some observers 

 claim that at least a part of the nymphs in spring hatch from eggs laid 

 in apple bark in the fall. The eggs hatch in about a week and the nymphs 

 feed for about 3 weeks, and the adults of these nymphs lay eggs for 

 another generation. In the middle Atlantic States there are three 

 generations each year, but this number may be reduced near the northern 

 limits of their range or increased farther south. 



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FIG. 182. Twigs showing injuries caused by the Buffalo Tree-hopper in laying its eggs. 

 About natural size. (From.Britton, Fifteenth Kept. Conn. Agr. Exp. Sta. 1915.) 



The injury caused by these insects appears to be a curling and check- 

 ing of the growth of the leaves in some cases, particularly those near the 

 tips of the shoots in the case of young apple trees. Older trees suffer 

 less than nursery stock. 



Control. Spraying thoroughly with nicotine sulfate 40 per cent, 

 1 part in 1,400 or 1,500 parts of water, with the addition of soap, is a 

 successful treatment to use for these insects if applied soon after the 

 nymphs appear in the spring, or at least before the leaves have curled. 

 Good results have also been obtained by dipping nursery stock in a 



