Insects, Diseases and Frost 



277 



Slugs (Empria, several species). 



In April or May, numerous pale, greenish caterpillars, about 

 three-fourths inch long with yellow or brownish heads, eat irregular 

 holes in the foliage 

 (Fig. 22). These are 

 the larvae of a small, 

 black, four-winged 

 saw fly, which lays 

 eggs on the plants 

 about two weeks be- 

 fore the blossoms 

 open. When not 

 feeding they stay on 

 the under side of the 

 leaf, coiled in a spi- 

 ral. Short rotations 

 and spraying with 

 arsenate of lead before 

 the blossoms open are 

 the best control measures 



Fig. 22. — Injury from slugs. 

 After the fruit is set, use hellebore. 



Root worms (Typophorus and Colapsis). 



These are the larvse of several species of common leaf beetles. The 

 adult beetles are black or reddish brown, one-eighth of an inch long. 

 They feed on the opening strawberry leaves in May and June, rid- 

 dhng them. The larvse burrow into the soil and feed on the roots of 

 the strawberry ; frequently they are mistaken for white grubs. The 

 beetles may be killed with arsenical sprays, but a short rotation is 

 the most practicable control measure. 



Crown girdler (Otiorhynchus ovatus). 



Occasionally strawberry plants are girdled an inch or more below 

 the surface of the ground by grubs. These feed on the roots but 

 rarely burrow into the crown as does the white grub. Infested plants 

 wilt and die. There are two generations in a season. The best 

 preventives are a short rotation and to avoid sod land. 



Ground beetles (Harpalus caliginosus and H. Pennsylvanicus) . 



In Pennsylvania, Ohio and New York, the common black ground 

 beetles have been known to destroy an entire strawberry crop in 



