110 INSECTS AFFECTING THE PEAR AND QUINCE 



year, and may at times cause severe injury in an orchard by 

 weakening the trees and stunting the fruit. A sweet " honey dew" 

 is secreted by them, which drops upon the leaves below, much in 

 the same way as in the case of the hop aphis, and woolly louse 

 of the alder, affording a fine culture for a black fungus, which gives 

 a blighted appearance to the foliage. 



Control Measures. This insect may be kept in check by up- 

 to-date orchard practice. Weeds and rubbish should be kept off 

 the ground and the rough bark scraped from the trunks and larger 

 branches. Spraying the trees on warm days in early spring with a 

 tobacco extract will kill many. Use one pint of nicotine sulfate 

 in fifty to seventy-five gallons of water, to which four pounds 

 of soap are added. The dormant spray as used for scale will kill 

 some, as well as the eggs of the first brood if present. Later, when 

 nymphs are on petioles, the above spray of tobacco extract and 

 soap may be employed, using it a little weaker (one pint of nico- 

 tine sulfate in one hundred gallons of water). 



FIG. 133. Blister mite. Greatly enlarged. (After Parrott, Hodgkiss and Schoene, Geneva 



Bull., 283.) 



Pear-leaf Blister-mite. Pear leaves with rusty blotches upon 

 them are likely to be found infested with this tiny mite (Fig. 133) 

 (not an insect), which lives within the leaf tissue. It is some- 

 times known as the plum gall-mite (Eriophyes pyri Pagen). See 

 page 118.) The eggs of the mite are deposited within a raised 

 blister or gall, which precedes the rust-like appearance above 

 alluded to, the young migrating from one leaf to another. Young 

 fruit may also be attacked. 



Control Measures. Spray in winter with lime-sulfur as prac- 

 ticed against scale insects. 



Pear Blight Beetle (Xyleborus dispar Fab.). The adult of 

 this insect is a very small brownish beetle, one-eighth to one- 

 sixteenth of an inch long, the round head nearly concealed by the 

 thorax (Fig. 134). The female bores in small branches and twigs, 

 causing the tips to die and to present a blighted appearance, hence 

 the name of the insect (Fig. 135) . The group of beetles to which 



