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THE BOOK OF WHEAT 



troduced into America in straw. It probably appeared first 

 in Quebec, and has now spread throughout the Mississippi 

 valley. The injury is inflicted by its orange-yellow larvae which 

 extract the milky juice from the embryos forming in the wheat 

 heads, thus causing the grain to shrivel and the heads to 

 blight. In cases of unusual outbreaks the average losses of 

 whole states have been from two-thirds to three-fourths of the 

 entire yield. The wheat midge oviposits directly in the wheat 

 head. The eggs hatch in about a week, and the larvae enter 

 the kernel at once. They have extraordinary vitality, thrive 

 best in moist weather, and winter in the ground, which they 

 enter about three weeks after hatching. Plowing old wheat 



WHEAT MIDGE: a, FEMALE; b, MALE; c, LARVA. ENLARGED 



fields deeply, burning the chaff and screenings of wheat from 

 infested fields, and rotating crops are preventives. 



The Wheat Plant Lice cause injury by sucking their food 

 from the soft, forming kernels. The yield may be reduced by 

 as much as one-half, but extensive damage rarely occurs. The 

 annual loss is thought to be at least 2 per cent. 



Locusts or Grasshoppers. The locust, formerly present in 

 some years in such overwhelming numbers that large swarms 

 devastated extensive areas of all vegetation, has during the last 

 decade ceased to be of such great economic importance. Locust 

 plagues seem to occur occasionally on all of the continents, 

 and do not seem to be limited to comparatively newly settled 



