lil) ANNUAL REPORTS 01 DEPARTMENT Ol AGRICULTURE, 1951 
Collections were made of parasites of the corn borer that lia<l been 
imported into this country and had become well established in the 
vicinity of older colon} sites. Approximately 160,000 parasites, com- 
prising 7 species, reared from borers collected in this country, were 
released in 1950 in areas more recently invaded by the borer, Ap- 
preciable numbers of the pesl are being desl royed by t hese enem • 
Distribution of DDF Residues <>n Corn Determined 
Studies of DDT residues on corn were carried out in cooperation 
with a manufacturer of the insecticide. Types of formulations used, 
distribution of DDT on the plant-, methods <>t" application, and time 
of applicat ion were considered. 
DDT emulsion sprays 1 * * fi larger deposits on corn plant- than a 
suspension of DDT wettable powder. Dust applications left smaller 
deposits of DDT than sprays. Aerial application- left smaller 
deposits t han ground applicat ions. 
The distribution of residue on different parts of the corn plant fol- 
lowed a fairly uniform pattern for all the formulations and type- of 
equipment. The leave- retained from 7" to 90 percent of the insecti- 
cide applied; t he whorl or top generally earned 1 5 to 25 percent : and 
the -talk', from ."» to in percent. After a short weathering period 
(here were indication- that residues from dusts and suspension sprays 
were lost rapidly from leaf surfaces and Lodged on the -talk. This 
w ;i- not t rue of emulsions. 
Study of date- of application for control of European corn borer 
on field coi'ii showed that weathering was more important than growth 
in reducing I >I >T residues. 
Some Wheats and Barleys Resistant to Hessian Fly 
The high resistance to the hessian fly of the wheat variety P. 1. 
56206 s has been transferred to a number of soft winter wheat-. 
This variety is also resistant to the race of fly that attack- W38, 
another generally fly-resistant wheat. Another fly-resistant wheat. 
3848 36, although it does not meet milling requirements, is showing 
promise in Indiana as an early-own wheat for fall grazing and ero- 
sion control. An outstanding hard winter wheat, C. 1. 12128, which 
has high resistance to the hessian fly as one of it- desirable characters, 
is being increased for early release in Kansas and Oklahoma. 
Seven varieties of hurley among 5,112 -train- tested in the green- 
house had very low plant infestations under heavy attack by the 
hessian fly. Studies of the inheritance of the resistance in crosses 
of 9ome oi the varieties are in progress and the eventual development 
of an agronomical ly desirable fly resistant barley is anticipated. 
The investigations on resistance of wheats and barleys to the hes- 
sian fly were conducted in cooperation with the Bureau of riant In- 
dustry, Soils, and Agricultural Engineering and the agricultural 
experiment stations of Indiana | Purdue), Kansas, and other States. 
Small Grains Threatened l»> Greenbugs and Other Peats 
Small grains in Oklahoma, eastern New Mexico, and the Texas Pan- 
handle, in the spring of L951, weir severely infested with greenbugs, 
