BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 63 
year. Studies were also initiated in Connecticut with special reference to the 
control of the flea beetles attacking tobacco in that section. 
The work in Virginia on the cigarette beetle and tobacco moth as pests of 
stored tobacco has been directed primarily along control lines. The utilization 
of a light trap in warehouses combined with hydrocyanic acid gas fumigation 
has resulted in a decided reduction in the quantity of stored tobacco destroyed 
by these two pests. Promising results have been obtained in preliminary tests 
with pyrethrum-dust mixtures directed against the adults of the tobacco moth 
in storage warehouses of the closed type. 
GREENHOUSE AND BULB INSECTS 
In continuing work with the gladiolus thrips in Maryland, greenhouse experi- 
ments show that sprays containing rotenone are not so valuable as paris green- 
sugar mixtures for controlling this pest, but no foliage injury accompanies 
such treatments. 
As a result of observations conducted in South Carolina on the insect vectors 
of the azalea flower spot disease, in cooperation with the Bureau of Plant 
Industry, it was shown that several species of bees were responsible for the 
dissemination of the organism causing the disease. These findings corroborate 
the tentative conclusions reached in the investigations performed on this project 
in 1934 and 1935. Additional information was obtained respecting possible 
methods of controlling the insect vectors. 
Tests against red spider mites and thrips on greenhouse-grown cucumbers 
and tomatoes in Ohio indicated that these destructive pests are partially con- 
trolled wtih sprays containing rotenone or with sprays containing organic 
thiocyanates, when properly applied in conjunction with suitable spreaders 
and wetting agents. 
Cooperative tests with State workers in North Carolina demonstrated that 
the bulb mite on tuberose bulbs can be controlled under commercial conditions 
by treatment with hot water, without injury to the treated bulbs. Further in- 
dications were that best results are obtained when the bulbs are planted either 
on newly cleared land or on soil that has been in cultivation but on which 
tuberoses have not been grown during the previous season. 
MUSHROOM INSECTS AND MITES 
Studies on the* control of mushroom pests have been continued in experi- 
mental mushroom houses at Beltsville, Md., and, in cooperation with mush- 
room growers, in Pennsylvania. Control experiments with the fumigants 
naphthalene and paradichlorbenzene indicated that the former was not very 
toxic to the mushroom fly and was injurious to mushrooms and spawn, whereas 
the latter fumigant gave promise in the control of insects and mites in bearing 
mushroom houses and did not appreciably injure the mushrooms or spawn. 
COTTON INSECT INVESTIGATION 
During May 1936 a new laboratory for cotton insect investigations was estab- 
lished by the transfer of two entomologists from Tallulah. La., to the Georgia 
Coastal Plain Experiment Station at Tifton, Ga. This laboratory was estab- 
lished to conduct studies on the control of the boll weevil and other cotton insects 
in a region where little attention has been given to this subject for many years. 
The studies will be carried on cooperatively with the State experiment station 
and should develop a program of cotton insect control suitable and practical 
for the southern coastal plain area. 
BOLL WEEVIL 
In the spring of 1935 boll weevil emergence from hibernation was lower than 
normal at all stations where hibernation studies are conducted, but was higher 
in South Carolina than at stations in Louisiana. Texas, and Oklahoma. During 
May and June in many areas conditions were SO favorable for the weevils that 
the prospects for heavy damage were serious. Midsummer weather conditions, 
however, checked the weevils so that no control measures were used on most 
farms. The heaviest damage occurred in Georgia and South Carolina. In 
