BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 
9 
throughout the Lake States. The information gained from 3 years' 
study on permanent sample plots indicates that much of the damage 
by these insects can be prevented by good silvicultural practices. 
CEREAL AND FORAGE INSECT INVESTIGATIONS 
DDT SHOWS PROMISE AGAINST VARIOUS CEREAL INSECTS 
Preliminary experiments indicate DDT to be a very promising in- 
secticide for use against the European corn borer, the white-fringed 
beetle attacking a variety of staple crops, the chinch bug as a pest 
of corn, the velvetbean caterpillar, grasshoppers, the vetch bruchid, 
and insects attacking stored grains and packaged cereal products. 
PROGRESS IN DEVELOPMENT OF INSECT-RESISTANT STAPLE CROPS 
Intensive experiments to utilize varietal resistance to infestation 
by insects attacking a number of staple crops are being continued in 
cooperation with Department and State experiment station agron- 
omists, with promising results. 
Big Club 43, a variety of wheat being increased for release in 1944 
to California wheat growers, showed high resistance to the hessian 
fly in two localities. This variety is also resistant to stem rust, bunt, 
and root rot. Thirteen promising advanced hybrids were included 
in eight adaptability test nurseries in Kansas. In Indiana high re- 
sistance to the hessian fly, mosaic, bunt, loose smut, leaf rust, and stem 
rust is being combined in advanced lines with good quality and yield. 
One of these fly-resistant hybrids outranked the standard varieties 
Fairfield and Trumbull in yield tests. Out of 201 varieties and hy- 
brid selections tested in the greenhouse at the Beltsville Research 
Center, 16 showed high resistance to the fly. 
In observations at Manhattan, Kans., 20 varieties of wheat and 9 of 
barley out of about 200 spring varieties of these crops tested were 
lightly infested by the chinch bug while other varieties were severely 
stunted. 
Corn varieties tested in Illinois showed two types of resistance to the 
earworm — reduction in damage to infested ears and inability of the 
larvae to become established. Eleven families and three individual 
lines of corn were rated as highly resistant. Among hundreds of 
lines examined in test plots in Mississippi, several showed low infesta- 
tion by the earworm and the rice weevil. Length and tightness of 
husk apparently were not the only factors responsible. 
Several alfalfa plants showing marked resistance to the pea aphid, 
a serious pest of alfalfa, were selected from many thousands of seed- 
lings tested at Manhattan, Kans., and passed on to the plant breeder 
for use in developing aphid-resistant strains of agronomic worth. 
Experiments in cooperation with the California Agricultural Experi- 
ment Station indicated that a synthetic variety having high resistance 
to aphicls and increased vigor of growth might result from systematic 
crossing of two separate aphid-resistant families. 
Progress has been made in methods of segregating the European 
corn borer and intensifying the resistance of field and sweet corn 
to this insect, and in utilizing this resistance on a commercial scale. 
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