2 
CIRCULAR 816, U. S. DEPARTMENT OF AGRICULTURE 
INTRODUCTION 
G rasshopper surveys supply the preliminary information needed for 
the most economical and successful conduct of control campaigns. 
This basic information consists of (1) the location and extent of the in¬ 
festation, and (2) its density. An important consideration pertaining to 
grasshopper surveys is their timeliness. The most successful control cam¬ 
paigns are necessarily planned well in advance of the field work, and 
surveys made early enough must maintain their reliability up to the 
time field control work begins. An egg survey made in the fall of the year 
gives the best results. 
For at least 25 years grasshopper surveys have been employed to pre¬ 
dict future populations. During that time the survey has evolved from 
one of reconnaissance to the present standardized type in which infesta¬ 
tions are classified into categories based on the number of egg pods per 
square foot of soil sampled. 23 Fall egg surveys are conducted by the 
Division of Grasshopper Control throughout the area subject to severe 
grasshopper damage, which includes nearly all the States west of the 
Mississippi River. Usually, .however, it is necessary to survey only a 
portion of this area in any one year. It has been customary to sample an 
average of 7 to 11 fields representative of each county, to obtain mean 
egg-pod populations. 
The egg survey is yielding serviceable results. In its present form, 
however, it requires a fairly large personnel and a great deal of travel. 
Delays due to adverse weather during the period available for surveying 
add to the labor problem. Any improvement that could reduce, without 
loss of accuracy, either the labor or the travel involved would result in a 
considerable saving of money. It also seems probable that some gain in 
accuracy can be obtained. Although it is evident that nothing can be 
done about the size of the area to be surveyed or about the prevailing 
weather, it is believed that field and county sampling methods can be 
improved. 
The conclusions drawn from the data presented in this paper have 
been found to apply to conditions prevailing in the northern Great Plains, 
where the species Melanoplus mexicanus (Sauss.) was dominant while the 
data were being obtained. Whether they will apply to other areas or 
species has not been determined; however, many of the principles of 
sampling will be applicable. The present paper is on the application of 
these and other related studies to problems of field population and sam¬ 
pling, especially to immediate problems of survey. 
SOURCES OF DATA 
Intensive studies of grasshoppers in typical environments were initiated 
by the Bureau's grasshopper research station at Bozeman, Mont., in 
1931. The studies were conducted on eight areas, each approximately 2 
2 Shotwell, R. L. a method for making a grasshopper survey. Jour. Econ. 
Ent. 28: 486-491. 1935. 
3 -SOME PROBLEMS OF THE ANNUAL GRASSHOPPER SURVEY. Jour. Econ. Ent. 311 
523-533. 1938. 
