ORCHARD INSECTS OF THE PACIFIC NORTHWEST 



29 



made known by the brownish drops of sap exuding from these punc- 

 tures. This loss of sap causes the buds to dry, and in the case of fruit 

 buds the blossoms may never open, or, if they do, they may be de- 

 formed. When the bugs are sufficiently numerous, the injury is severe 

 (fig. 33) and may result in almost a total failure of the crop. The de- 

 gree of injury is contingent not only on the number of bugs, but on 

 weather conditions. Continued periods of settled warm weather in 

 March or early in April, coming before 

 alfalfa and other ground crops have devel- 

 oped, cause the bugs to feed in the trees; 

 cold, rainy, or windy weather at this time 

 prevents extensive feeding. Pears and 

 Delicious apples are the most susceptible 

 to this injury. The bugs also sometimes 

 feed on the young (fig. 34) and maturing- 

 fruit and cause dry or corky and sunken 

 spots. The tarnished plant bug occurs 

 throughout the Northern Hemisphere; its 

 origin is uncertain. 



LIFE HISTORY 



The adult tarnished plant bugs are nearly 

 one-fourth of an inch long, dirty grayish or 

 greenish, with variable markings. They 

 come out of hibernation during the first 

 warm, sunny days of early spring and feed 

 for a time on fruit-tree buds, and the 

 leguminous cover crops. They are quite 

 active, flying readily or moving around to 

 the opposite side of a twig or bud when 

 approached, and are not easily seen. Eggs 

 are laid in the tender shoots or in the 

 flower heads of a number of plants, and the 

 nymphs, which resemble the adults, except 

 that they are smaller and have no wings, 

 feed chiefly on cover crops and weeds. 

 Growth is attained in less than a month, 

 nymphs going through a series of molts as 

 they increase in size. There are three or 

 four broods during the season, and the bugs 

 are often very numerous in the fall. Large 

 numbers of these bugs die when the first 

 cold weather comes and the mortality among those hibernating is 

 apparently high. 



CONTROL 



No very satisfactory method of controlling the tarnished plant 

 bug has been devised. Something can be accomplished by cleaning 

 up and burning trash which may accumulate about buildings, and 

 burning grass and leaves along fence rows. Burning should be done 

 during cold weather in order to destroy the bugs before they can escape. 

 It must be done with great care about orchards, as trees are very easily 

 injured by fires near them, and fires sometimes escape into the orchards 

 themselves. Destruction of trash in the orchard by this means is 

 not advised, for the trash usually forms part of the orchard mulch 



Figure 32. — Tarnished plant 

 bug feeding on peach bud. 

 X 2. 



