April, ’24] 
LOCKWOOD: GRASSHOPPER DAMAGER 
197 
tendency to attribute to one conspicuous factor like the boll weevil the 
damage actually attributable to a number of causes. The trend in 
these estimates is undoubtedly towards exaggeration, as has been shown 
by many comparisons between Crop Reporting Service estimates and 
those made by entomologists which have been made by students in 
the Department of Agriculture. 
The Department is now conducting a large experiment in increasing 
the accuracy of crop correspondents estimates of weevil losses. Ex¬ 
perts of the Bureau of Entomology and Plant Industry have drawn up a 
questionnaire which has been sent to about 150,000 farmers throughout 
the South. This questionnaire will make it possible to correlate re¬ 
ductions in the crop with many factors entering into its production, in¬ 
cluding varieties, time of planting, spacing and many others. It will 
also furnish a basis for correlating different methods of weevil control 
and production. According to the statisticians it will yield the largest 
number of variables which have ever been considered in any statistical 
inquiry. The work of tabulating and correlating on special machines 
will occupy the time of several men for a number of months. The out¬ 
come of this inquiry can not be foretold, but it probably will yield 
very favorable results. 
The commercial estimates of weevil losses in many cases are made 
through the reports of local correspondents. In many cases the number 
of correspondents is small and it is suspected that some of the estimates 
are merely evolved in offices in New York, New Orleans or other 
places. While many of the estimates are made with care and good 
intent, there is always the possibility that any commercial report may 
be colored by the bull or bear interest of the concern which makes it. 
ESTIMATING THE ABUNDANCE OF, AND DAMAGE 
DONE BY GRASSHOPPERS 
By Stewart Lockwood, In charge Billings Laboratory, Bureau of Entomology 
Abstract 
Because of extreme activity the numbers of grasshoppers, Acrididae, are hard to 
estimate. By aid of a field glass the observer can stand at some distance and count 
those in a given unit. Many units of ground should be so counted in a field before an 
estimate of the grasshoppers can be made. 
A knowledge of the egg laying habits is necessary before an estimate of the number 
of eggs in a locality can be made. 
Estimating the per cent of damage in a particular field is done by comparison of 
the amount of damaged seed in several small units with the undamaged seed. 
