46 Farmers’ Bulletin 1169. 
more abundant in the Middle West than in the East, although it is 
more or less generally distributed east of the 100th meridian. 
Remedies.—On specially prized smaller plants some relief from 
this pest may be obtained by hand picking and destroying the cater- 
pillars. Sizable trees should be sprayed with lead arsenate (p. 11) 
as soon as the caterpillars appear, to protect them from defoliation. 
In case of maple groves or suitably located individual trees it has 
Fig. 27.—Cluster of full grown walnut caterpillars, showing peculiar poses, long hairs, 
and clustering habit. (Photograph by Cramer, Washington, D. C., Sept. 27, 1919.) 
been found possible to protect them from a repetition of defoliation 
by digging around them a trench about a foot deep, with the outer 
wall sloping under, and destroying the caterpillars and pupe that 
collect in them. 
WALNUT CATERPILLAR.” 
How injurious —When there are enough of them, these caterpillars 
(fig. 27) strip walnut trees bare of leaves. Other trees also, 
especially butternut and hickory, are likely to suffer the same fate. 
22 Datana integerrima G. & R. 
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