28 



CIRCULAR 2 7 0, TJ. S. DEPARTMENT OF AGRICULTURE 



more than 6 or 8 feet above the ground, and young trees are most 

 often attacked. Frequently the growth of such trees is seriously 

 retarded. Injury is practically confined to the current season's 

 growth and to 1 -year-old wood, but the old scars persist for some 

 years. Apple and pear trees are the most subject to injury, although 

 peach, cherry, plum, and quince are occasionally affected. 



LIFE HISTORY 



The whitish, cylindrical eggs of the treehoppers are about one- 

 tenth of an inch long, and from 6 to 20 of them are placed side by side 



in each slit, the ends 

 usually being visible. 

 They are deposited 

 during the period 

 from July to Septem- 

 ber and hatch the 

 following April or 

 May. The young, or 

 nymphs, drop to the 

 ground and feed 

 chiefly on alfalfa, 

 where they are most 

 often found in the 

 center of the crowns. 

 Growth is completed 

 in July. The adult 

 insects are about 

 three-eighths of an 

 inch long, grayish or 

 greenish, and trian- 

 gular, and the com- 

 moner species have 

 projecting pronotal 

 horns, suggesting the 

 appearance of a buf- 

 falo. 



CONTROL 



Clean cultivation 

 is the most obvious 

 and practical control 

 method and should 

 be practiced in young 

 orchards whenever possible. As the trees bec°me older, cover crops 

 may be planted, for the injury is less severe on older trees. Many 

 of the worst-scarred twigs can be pruned off during the winter, and 

 should be burned to destroy the eggs. A thorough dormant spray 

 containing 4 percent of lubricating-oil emulsion kills most of the 

 eggs in the twigs and may reduce the infestation the following year. 



Tarnished Plant Bug 



The tarnished plant bug (Lygus oblineatus (Say)) (fig. 31) appears 

 in the trees early in the spring and punctures the swelling fruit and leaf 

 buds (fig. 32), sucking the sap from them. Its presence is often first 



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Figure 31. — Tarnished plant bug. X 12. 



