BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 29 
Iii adjacent localities it ranged from 36 to 96 percent. The present 
abundance of these parasites, their ability to destroy a high propor- 
tion of several important range species of grasshoppers and the ease 
of obtaining their eggs and larvae in large numbers, suggest the 
possibility of introducing them into range areas where they are now 
absent or present in small numbers only. 
A fungus identified as Empusa grylli was a major factor in re- 
ducing populations of Melanojrtus Mvittatus in certain sections of 
Montana. In one section of that State, Aeropedellas clavatus was 
practically wiped out by this fungus. 
Grasshoppers killed with new insecticides 
Early season tests in Arizona with emulsions of aldrin, dieidrin, 
heptachlor, compound 1189, and Dilan, applied with a mist blower 
to alfalfa gave excellent control of grasshopper nymphs. These tests 
were repeated later in the season on larger plots in Arizona and 
Montana. Dieidrin at % to 1 ounce and heptachlor at 6 to 8 ounces 
per acre resulted in 93 to 97 percent mortality in Arizona. Solution 
sprays were tested on Montana range land — dieidrin at y 2 ounce an 
acre, aldrin at 2 ounces, and heptachlor at 3 to -i ounces — and they 
also gave satisfactory kills. 
Tests were made to study the residual effectiveness against grass- 
hoppers on alfalfa of spray applications of aldrin, compound 1189, 
dieidrin, and Dilan. Aldrin lost much of its effectiveness after 28 
days but continued to kill up to 19 days. Compound 1189 compared 
favorably with aldrin but gave no kill after 41 days. Dieidrin was 
still effective after 62 days. Dilan had no residual effect after 9 days. 
All of the insecticides which have proved effective for grasshopper 
control in the Western States were equally efficient in Florida against 
the American grasshopper. 
New Trends in Grasshopper Control Campaign 
Farmers and ranchers step up grasshopper control on crop and 
range land 
States and minor civil divisions have continued their cooperative 
responsibility for providing technical direction and help in grass- 
hopper survey and control in crop areas. Farmers do the actual 
control work on their croplands. On privately owned range land 
increasing numbers of ranchers are finding it profitable to carry on 
grasshopper control under the same plan as farmers in crop areas. 
Where grasshopper control on private range is too extensive for in- 
dividual handling, the problem is currently being met by cooperating 
States, counties, and individuals providing at least two-thirds of the 
cost and the Bureau the remainder. Where grasshopper or Mormon 
cricket infestations on lands owned or controlled by the Federal Gov- 
ernment require control, it is the responsibility of the Bureau, as the 
appropriate operating agency of the Government, to conduct the neces- 
sary survey and control operations. In cooperation with the States, 
surveys of grasshopper adults were made in 1951 in 811 counties in 
22 States, and egg surveys in 460 counties. 
Much of the control work required during this fiscal year has been 
on public domain. Federal agencies, including the Forest Service, 
