BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 
11 
ing local infestations and may eliminate the need for more extensive 
and costly control operations in subsequent seasons. 
REPLACEMENT OF BROADLEAFED WEEDS BY GRASSES ON ROADSIDES AND FIELD 
MARGINS GREATLY REDUCES GRASSHOPPER EGG LAYING 
Observations during 1943 confirmed those of previous years that 
the numbers of grasshoppers and their eggs are greatly reduced in 
roadsides and field margins, important grasshopper breeding places, 
when broadleafed weeds are replaced by nearly solid stands of grass. 
ADDITIONAL MORMON CRICKET OUTBREAK CENTERS LOCATED 
In connection with field ecological studies new centers were located 
where Mormon crickets persist during periods of general scarcity, six 
of them in Nevada and one in Wyoming. The location of such areas 
and the control of this pest therein may result in prevention of general 
outbreaks at comparatively low cost. The studies indicated that hatch- 
ing of crickets in such areas is delayed by continued cold until so late 
in the spring that there is little likelihood the crickets will be killed by 
adverse weather subsequent to hatching, as they often are in localities 
in which climatic conditions are less favorable. 
NEMATODES PARASITIC ON WHITE-FRINGED BEETLE 
An intensive investigation of certain nematodes known to be para- 
sitic on the white-fringed beetle, a serious exotic pest of staple crops 
in the Gulf States, has shown these nematodes to be common both 
inside and outside the infested areas but apparently not a dominant 
factor in keeping down the numbers of the beetle. 
INSECTS IMPORTANT FACTORS IN ALFALFA SEED PRODUCTION 
Although Lygus spp. and other sucking bugs that attack alfalfa 
seed and hay crops in Arizona and Utah were much less abundant in 
1943 than in the peak year 1941, their injury to the seed crop in Ari- 
zona was estimated to be over $500,000. Observations in that State 
indicated that suitable cultural practices provided considerable pro- 
tection when applied on individual farms as well as throughout a 
community. As much as 90 percent of the alfalfa blossoms of plants 
attacked by sucking bugs may fail to set seed. This failure is appar- 
ently due largely to the scarcity of the wild and domestic bees necessary 
to effect pollination. Studies are now in progress in cooperation with 
the Utah Agricultural Experiment Station on the utilization of bees 
to increase pollination. 
NEW DEVELOPMENTS IN CONTROL OF INSECTS ATTACKING STORED GRAINS AND 
MILLED CEREALS 
Six organic compounds showed considerable promise in preliminary 
tests as substitutes for the standard grain fumigants, the supplies of 
which are more or less limited by war conditions. Several materials, 
including white lead paint, whitewash, and a solution of nicotine sul- 
fate, were highly effective in preventing the cadelle and the lesser 
grain borer from burrowing and persisting in the woodwork of wooden 
grain bins and infesting grain newly stored in these bins. Several 
organic and inorganic dusts, including DDT and magnesium oxide. 
