3 I ANNUAL REP0BT6 01 DEPARTMENT Of AGRICULTURE, 1949 
the cotton in that area was defoliated. Farmers were forced to tr< 
around infested fields and (ill the ditches with water to prevent the 
caterpillars from moving into other fields. In field experiments Bu* 
found thai a dust mixtu lining toxaphene, 
DDT, and sulfur reduced the infestation to a very low point This 
icide matei ial ever found to give good control of these 
caterpillars on cotton. 
Other cotton insects 
Toxaphene, benzene hexachloride, DDT, and mixtures of i 
found u go d cont rol of the principal cotton in 
wciv also i ffecf -i the cotton fleahopper ana plant bugs. In 
the fourth community in Wharton County, Tex., that was included 
iii the cooperative * xperiment for control of cotton insects, the flea- 
hopper was the most damaging pest. A total of 1.111 acres on 47 
farms dusted twice with 1" percent of toxaphene. The effect on 
fruiting and maturing of the bolls was the same as in the other com- 
munities, and the yield of lint cotton showed a gain of L10 pounds 
per acre over that in an undusted community uearby. 
In experiments in Arizona benzene hexachloride, DDT. and toxa- 
phene were about as effective against plant bugs when applied in con- 
cent rated sprays as in dusts. Against stink hugs benzene aexachloride 
\. as d tive than t he ot her t wo insecticides. 
S rious damage from the cotton fleahopper in L948 was confined 
ly to the Gulf coast section of Texas and the Santa Cruz Valley 
of Arizona. Plant bugs and stink bugs on cotton in the Irrigated 
sections of the Southwest were less abundant than in any recent year. 
Progress Made in Basic Research on Cotton Insects 
Research to determine the fundamental factor- governing the ef- 
fectiveness of various measures for controlling insect pests of cotton 
1 in Texas and Mississippi with funds authorized by the 
irch and Marketing A.ct of L946. These factors include reactions 
of insects to different control measures and the reactions of the plant 
to insect attach and to the insecticide. Studies were made with a 
large number of aew insecticides and combinations of insecticides, 
chiefly under laboratory or cage conditions. During the year it was 
demonstrated that both benzene hexachloride and parathion are com- 
patible with calcium arsenate low in free lime and that the essentially 
pure gamma isomer ot* benzene hexachloride is less compatible than 
the technical grade containing several isomers. Evidence was ob- 
tained that the new insecticide known chemically as octamethyl- 
pyrophosphoramide is absorbed by cotton plant- in sufficient quantity 
to kill red spider mil 
Pink Bollworm Quarantine Activities 
Hi suits of insf/ection 
I tensive inspections of the 1948 cut ton crop for the pink bollworm 
carried on within regulated area < f \' zo a, New Mexico. Okla- 
homa, and Texa . and outside the regulated areas in these and other 
