INSECT PEST SURVEY BULLETIN 
Vol. 19 Summary for 1939 No. 10 
INTRODUCTION 
The weather of 1939 followed, the general trend, of abnormal warmth for the 
last several years. The winter of 193&-39 was unusually warm over the entire 
country, very dry in the fall, hut there was abundant rainfall during the win- 
ter so that spring started with plenty of soil moisture. 
The spring months were warm and dry except in the northeastern quarter of 
the United States, where unusually cool, wet weather prevailed. 
In June and Julv the temperature generally was near normal. Rainfall was 
varied, being abundant in Ohio Valley and the Southern Atlantic States. Much 
of the West, the Plains States, and the Northeastern States were deficient in 
rainfall, 
August was very hot over the entire country and very dry, except on the 
west coast and in the Southeastern States. 
September also brought abnormally high temperatures and widespread de- 
ficiencies in precipitation. A severe and widespread drought developed through- 
out the Great Plains and the central valley. The abnormally warm dry weather 
continued into October, rain being scanty except in the northeastern part of th< 
country. 
The weather was favorable for grasshoppers, as it was rather warm and dry 
at the time o± hatching. It also facilitated development of the young hoppers, 
and allowed rapid movement into cultivated crops. 
ihe spring was cool and wet in much of the chinch bug belt, proving un- 
favorable to the development of the insect. On the other hand the warm, dry 
weather in the fall favored development of the insect, allowing more nymphs to 
mature and, consequently, a heavy population went into hibernation. 
The warm dry fall had an indirect effect on the hessian fly, the wheat 
sown prior to fly-free dates being slow in germinating because of the lock of 
soil moisture. 
GRASSHOPPERS 
Severe infestations occurred in all states west of the Mississippi River, 
especially in the northern Great Plains States. At the time when grasshopper 
rf° S W f r ! hatchln ^» these insects were favored by the warm, dry weather which 
h-lT'rfl °T T t ° f infested area * In the South hatching started the latter 
S'f C April and continued without interruption so that by the end o5 Mnv 
. S f^ S : and - Mliiiatus Say were entirely thnoygh hatching 
P solated districts, M, differential is was later in developing. By 
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