BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 19 
bers in many areas early in the season, but were brought under control 
with insecticides. Mid-season and late-season infestations were very 
low, with the exception of localized areas, one of which was in the 
Safford Valley. Stink bugs were found in many fields when the cotton 
was still in the seedling stage. Fortunately they soon moved on, 
causing little or no damage. 
DDT continued to be effective against lygus bugs. A mixture con- 
taining 5 percent of DDT plus sufficient BHC to give 2 percent of 
gamma proved very effective against both lygus and stink bugs. 
Toxaphene was also effective against lygus but inferior to the DDT- 
BHC mixture against stink bugs. Experiments showed that dieldrin 
applied at the rate of 0.25 pound per acre was effective against lygus. 
For stink bugs the amount had to be increased to 0.5 pound. 
Sprays Give Good Initial and Residual Control of Thrips on Cotton 
Thrips control experiments were conducted near "Waco, Tex., both 
small plots and large fields being utilized. The predominant species 
of thrips was Frankliniella exigua Hd., with F. fusca (Hd.) present 
in smaller numbers. Good control of thrips was obtained with the 
following spray treatments and per acre dosages: dieldrin 0.1 pound; 
toxaphene 0.75 pound; aldrin 0.125 pound; heptachlor 0.125 pound; 
and EPX 0.25 pound. Satisfactory initial control with poor resid- 
ual action was obtained with 0.15 pound of the gamma isomer of 
BHC plus 0.25 pound DDT; 0.15 pound of the gamma isomer of 
BHC; EPN 0.125 pound; endrin 0.1 pound; and isodrin 0.15 pound. 
Unusually Heavy Spider Mite Infestations in Cotton 
Spider mite infestations were unusually heavy in most cotton 
growing areas in 1952, necessitating the widespread use of control 
measures. In experiments conducted at Stoneville, Miss., and Waco, 
Tex., Systox at 0.25 pound per acre gave excellent initial control and 
was residually effective up to 15 days following treatment. Either 
EPN or methyl parathion at 0.25 pound per acre gave good control, 
but neither was as residually effective as Systox. Parathion and 
Metacide each gave good initial kills but reinfestations occurred in 4 
to 7 days. Aramite at 0.3 to 0.5 pound per acre gave fair to good 
control after about 4 days, but in about 2 weeks the population in- 
creased rapidly. Malathion at 0.34 pound; R-242 at 0.5 to 1 pound; 
and p-chlorophenly p-chlorobenzene sulfonate at 1.5 to 2 pounds per 
acre each gave fair to good control. 
FOREST INSECTS 
Ponderosa Pine Susceptibility to Beetle Attack Depicted by 
Foliage Color 
Foliage color has proved one of the important tree characteristics 
in classifying ponderosa pine according to its susceptibility to western 
pine beetle attack. A technique which involves black and white pho- 
tographic enlargements into which color is worked by hand processing 
has been devised for properly depicting risk classes in color. 
