36 



CIRCULAR 270, U.S. DEPARTMENT OF AGRICULTURE 



in April and early May and the small white hoppers commence to 

 feed at once on the new foliage, remaining among the pubescence 



Figure 42.— Flat-headed apple-tree 

 borer (adult). Three times natural 

 size. 



Figure 43.— Flat-headed apple-tree 

 borer. Slightly enlarged. 



m 



of the underside of the leaves. Growth is attained in three or four 

 weeks, and the adults live for a month or more. Eggs are laid in the 

 tissue of the leaves from May to July, and do not hatch for over two 



months. The second brood of 

 young thus appears late in July 

 and in August, and adults are 

 present again from August to 

 November. These lay winter- 

 ing eggs in the bark of the 

 young wood, where they appear 

 as small raised blisters. 



The green apple leaf hopper 

 (Empoasca maligna Walsh) has 

 only one generation a year, 

 starting with the wintering eggs, 

 which are usually laid in the 

 bark of wood 2 or 3 years old. 

 The eggs hatch in April, and 

 the young, which are light green 

 instead of white, feed in the 

 same manner as do the white 

 apple leaf hoppers. The green 

 adults appear in May and some 

 are still present in July. Most 

 of the eggs are deposited in May and June, and these remain in the 

 bark until the following April. Since it has only a single generation 

 annually, this leaf hopper does not become as numerous as the white 

 species. 



CONTROL 



The most effective means of controlling leaf hoppers is the use of a 

 spray of nicotine sulphate (40 percent nicotine) in the proportion of 

 y 2 pint to 100 gallons, used with an oil emulsion, or with 2 or 3 pounds 



Figure 44.— Work of a shot-hole borer, Scolytus 

 rugulosus. 



