2 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 194 1 
year has been concentrated largely in essential grass <»r turf areas in 
military establishments, particularly on airplane landing fields. 
The development of an improved grasshopper bait spreader and 
advancement in the application of insecticide- from the air also fur- 
nish gratifying evidence of progress in insect control. Not so satis- 
factory has been the situation with respect to the pink bollworm on 
cotton. The spread of this insect to Louisiana, where a noncotton 
zone is in effect in Cameron Parish, and the discovery of infer-tations 
in three add it ional Gulf coast counties give cause for concern. 
In this report will be found numerous references to investigations 
on the insecticide 2.2-bis(/;-cldorophenyl)-l.l.l-trichloroethane, the 
common name of which is DDT. The total output of this material in 
this country at present is being devoted to the needs of the armed 
forces, with the exception of a small amount that is being used for 
experimental purposes. Although results now available indicate 
that it will be an important agricultural insecticide, it is necessary to 
learn more about its effectiveness against various injurious insects and 
the quantities and concentrations needed for their control. Addi- 
tional information will have to be obtained with respect to its effect 
on plants and beneficial insects and what, if any, hazard to human 
beings and animals may be associated with its use. 
FRUIT INSECT INVESTIGATIONS 
CONTROL OF THE CODLING MOTH WITH DDT INDICATED 
The new organic insecticide DDT gave remarkable control of the 
codling moth in preliminary field tests carried on at Vincennes, Ind., 
beginning late in July 1943. Three applications of 3 pounds of a 
50-50 DDT-pyrophyllite mixture per 100 gallons without supplements 
completely stopped a heavy worm attack for the remainder of the 
season. Where the DDT-pyrophyllite mixture was used at only L5 
pounds per 100 gallons, the fruit averaged only 31 worms per 100 
apples as compared with about 100 worms per 100 apples following the 
lead arsenate program. In some field experiments the DDT permitted 
hu ge increases in the population of European red mites, apparently 
by killing or repelling certain ladybird beetles that prey on the mites. 
Considerable defoliation occurred on trees of the Grimes variety 
sprayed with DDT, but this may have been caused by the abundant 
mites. No defoliation occurred on trees of the Winesap variety. 
OTHER INSECTICIDES TESTED ON THE CODLING MOTH 
A t Yakima. Wash., the met hod of using xanthone for cont rolling the 
codling moth in the Northwest was improved to the point where *2 
pounds to 100 gallons gave better results than :\ pounds of lead ar- 
senate. For the third season this insecticide greatly reduced the pop- 
ulation of the Pacific mite. Field tests with a dinitro-o-cresol spray 
to destroy hibernating codling moth Larvae, made on a larger scale 
than previously, killed SO to !>t percent of the Larvae and reduced the 
subsequent infestation in fruit 25 to 50 percent 
Although phenoi hiazine has given :i high degree of kill of the cod- 
Ling moth in the Northwest, no way has vet been developed to prevent 
it- adverse effect on the color of red apples, and work with it has been 
hugely discontinued tor the present. 
