BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 37 
control campaign. The heaviest infestations were centered in Michigan, 
Wisconsin, Minnesota, North Dakota, and Montana, bul grasshoppers occurred 
in sufficient abundance to require control in the States of South Dakota. Iowa, 
Colorado, Wyoming, Kansas, Arizona. Idaho, California, Nevada, and New 
Mexico. A considerable portion of this reduction in populations, compared 
with 1934, may be attributed to the success of the control campaign. The in- 
festation in the northern part of North Dakota and Minnesota was undoubtedly 
increased by migrations of grasshoppers from Canada. The requirements of the 
various infested States for control in the spring of 1935 were successfully met 
with the funds and materials available. 
CHINCH BUG 
After the completion of the control campaign late in the summer of 1934. 
a survey of chinch bug abundanee was conducted, cooperatively with various 
States in the Corn Belt, to determine their probable abundance in the spring 
of 1935. This survey revealed the presence of the highest overwintering popu- 
lations of chinch bugs on record in Ohio, Indiana, Illinois, Missouri, and 
Iowa, and populations of menacing proportions in the States of Oklahoma, 
Kansas, and Nebraska, and in southern Minnesota. Wisconsin, and Michigan. 
A considerable increase in the area covered by the infestation was also observed. 
Recognizing the emergency nature of this situation, should spring weather 
conditions be favorable for chinch bug development, Congress appropriated 
$2,500,000 for the control of these insects. The very cold, wet spring delayed 
migration until after June 30, the indications being that, although severe local 
outbreaks could be expected in some of the States involved, the extremely 
wet weather over most of the area bad reduced the outbreak to a level at 
winch it was not so serious as that occurring in 1934. In Oklahoma, Kansas, 
and Nebraska the infestation was practically eliminated. Detailed studies 
on improving barrier methods and materials, and in determining methods of 
preventing severe infestation by reducing or eliminating certain of the small 
grains are being made, and more accurate methods of evaluating chinch 
bug abundance have been developed. 
EUROPEAN CORN BORER 
In the summer of 1934, in addition to the usual abundance surveys made 
in selected areas known to be infested, a survey was conducted to discover any 
extension of European corn borer invasion around the margins of the known 
infested area. This survey revealed only minor spread of the borer during 
the past 2 years. Damage surveys indicated extensive loss to sweet-corn 
growers along the eastern seaboard, particularly in Massachusetts and Con- 
necticut, and on Long Island. An increase in infestation was noticed in Ne ' 
Jersey and in two counties on the Eastern Shore of Virginia. However, 
infestations in the one-generation area in western New York, Ohio, and Indiana 
has maintained approximately the same degree of severity for the past 3 years 
During this period climatic conditions have been definitely unfavorable to 
corn borer increase. 
Varieties of field corn resistant to corn borer attack have been further 
tested and have maintained their resistance to the borer. In cooperatio 
the Bureau of Plant Industry, further crosses have been made of these res ; - 
varieties, and an effort is being made to discover new resistant characters and 
new strains resistant to the borer. This work has now been extended t<> 
studies of resistance in sweet corn for utilization in the sweet-corn canning 
areas and market producing centers. 
ALFALFA APHID 
Resistance of alfalfa to the attack of the alfalfa aphid, approaching 
immunity, has been definitely proved in a number of strains Belected 
varieties of alfalfa widely grown in Kansas and California. ains 
have been carried through a number of generations and subjected («• severe 
test. Results indicate that resistance is Inherited. Repeated attempts i<> Isolate 
strains of aphids that are able to survive on the resistant plants have resulted 
in failure. An effort is being made, in cooperation with the Bureau of Plant 
Industry, to develop strains of alfalfa having desirable agronomic characters 
combined with resistance to aphid attack. 
