46 awtai. REPORTS of DEPARTMENT OF AGRICULTURE, 1 | 
The Dutshells examined were almond, coconut, filbert, pecan, and wal- 
nut. Forest products included redwood and southern pine bark, wood 
Hour, and sumac leaves. Other material- were peach and apricot pit 
shells, rice hulls, peanut shells, eorncob tractions, corn stover, llax 
shives, hemp huras, wheat straw, tobacco dust, and residues from 
castor-oil filtration. There are indication- that when finely ground 
these plant materials are more uniform inparticle size than the mineral 
diluent.- now used for insecticides. DDT wettable powdera prepared 
with some of these materials as diluents are also being tested. I 
studies are conducted with funds provided under the Research and 
Marketing Ad of L946. 
METHODS OF DISINFKSTING AIRCRAFT IMPROVED 
A combination of residual and space treatment- lias been found 
experimentally to aid m preventing insects from hitchhiking by air- 
plane. Residual insecticides, applied in carbon-dioxide-propelled 
solul ions, remained toxic Longer than the period of the air trip, bui did 
not leave an unsightly deposit or have an injurious effect on the siir- 
face material. Space aerosols, released in fixed installations in the 
plane, gave further protection because the fine particles penetrate 
even the small cracks and crevices where insects can stow away. 
The automatic equipment for dispersing these aerosols, modified 
and perfected by the Bureau in cooperation with several other gov- 
ernmental agencies, has now been tested under operating conditions. 
The apparatus consists of a centrally located aerosol supply tank 
connected to a manifold system of aluminum or copper tubing, with 
outlet- for nozzles located at suitable places in the interior of I he plane. 
The flow of liquid is controlled with solenoid valve-, and the dosage. 
is regulated by a mechanical timing device. Dispensers have been in- 
stalled in two planes of the .Military Air Transport Service operating 
out of Honolulu, and on July 1, L948, had given satisfactory service 
for months. 
WORK ON MECHANICAL DEVICES FOR USE IN PEST 
CONTROL COORDINATED 
Recent coordination in tin 1 development and use of machinery and 
ot her device- in plant -pest control has resulted in the general improve- 
ment of several import nut pieces of equipment and in the design of two 
entirely new item-. This activity al-o afforded means of advising 
field stations on the availability and proper use of special machines and 
thus eliminated much independent invest igation and consequent dupli- 
c:it ion of effort. 
The urgency of the grasshopper-control problem in the Western 
States required prompt action in providing equipment t<» meet the 
emergency. The new type of bait developed tor this purpose required 
new machinery for spreading it. Special equipment using air as the 
dispersing medium wa? designed and installed ma 1 )( ' 3 plane, which 
h:i con istenth baited more than 20,000 acre- per daw 
