44 Farmers’ Bulletin 1260. 
veloped or damaged shuck covering. In cornfields, especially in the 
South, where insect infestation occurring in the field is most severe, 
there are a sufficiently large number of exposed kernels to bring about 
shght, though widespread, infestation. 
It is probably true that in well-grown crops of corn the percentage 
of kernels infested before the crop is ready for harvest is very small, 
and throughout the Middle and Northern States is a negligible fac- 
tor. In the Gulf Coast States, especially in upland fields, the infes- 
tation often is very severe. In the case of wheat, grown particularly 
along the Ohio River, in southern New Jersey, in Pennsylvania, 
Fic. 62.—Grain mites. (Howard.) 
Maryland, Delaware, Virginia, and southward, the field infestation 
may be much more general than is now believed. Newly thrashed 
wheat from Maryland arriving in September on the Baltimore mar- 
ket showed infestation ranging up to 6 per cent. While these infes- 
tations occurring in the grain before it is harvested are usually un- 
avoidable, they are of great importance as “ leaven ” which in storage 
may result in a general infestation of an entire crop, in heating, and 
in much damage. 
After grain has been harvested it is often stored in bins, store- 
houses, or barns that have held. or still hold, infested grain and which 
