BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 41 
and orthodichlorobenzene in oil. Western white pines and lodgepole 
pines infested with mountain pine beetles were used. Preliminary re- 
sults indicate that all of these formulations were equally effective in 
controlling mountain pine beetles in these trees. For control of the 
Black Hills beetles in ponclerosa pine, ethylene dibromide emulsions 
continue to prove effective. These results, in keeping with those 
previously reported for the Engelmann spruce beetle, indicate a wide- 
spread gain in the reduction of direct control costs of several of our 
most important bark beetle pests. 
New Device Improves Spray Distribution From Helicopter 
An apparatus has been developed for use on a helicopter to improve 
spra}^ distribution and to deposit heavier dosages of DDT insecticides 
from the air. This device utilizes air from the engine cooling fan and 
from the exhaust stacks to assist in breaking up the spray as it leaves 
the helicopter. It, therefore, produces finer atomization of spray at 
slow speeds than the nozzle-boom-type of spraying apparatus that 
has been used heretofore on helicopters. In comparative tests with 
airplanes and helicopters to determine their relative effectiveness in 
applying sprays to control the gypsy moth it was found that both 
machines provided complete control with dosages of 1 pound of DDT 
per acre. In these tests, however, the helicopters deposited twice the 
amount of DDT deposited by the airplane from a given amount of 
spray. In contrast with effective control of the gypsy moth it was 
found that the European pine shoot moth infestations were not satis- 
factorily controlled when as much as 4 pounds of DDT in 4 gallons 
of oil were applied to red pines. The State of Connecticut cooperated 
in some of these studies. 
Sprays Tested for Control of Several Destructive Forest Insects 
Several insecticidal formulations were tested in unsuccessful at- 
tempts to control Matsucoccus scales on red pine. On the other hand, 
applications of Aramite, Dimite, and Oratran with mist blowers gave 
good control of spider mites when used at dosages of 5 to 8 gallons 
per acre. By applying lead arsenate to the leaders of white pine re- 
markable control of the white pine weevil was obtained, with only 8 
infested trees showing up among 21,000 that were treated. The State 
of Connecticut cooperated in these studies also. 
Means of Recognizing Incipient Infestations of Spittlebugs Found 
Improved methods were sought for surveying Saratoga spittlebug 
infestation, and for evaluating the use of DDT sprays for controlling 
it in plantations. These studies were conducted in cooperation with 
the United States Forest Service on national forests in Wisconsin and 
Michigan. It was observed that spittlebug feeding causes a reducl ion 
in shoot growth, and that this can be detected by growth measure- 
meats. The practical value of this development lies in the use it may 
have in providing a method for recognizing outbreak- in their early 
stages, thereby permitting the application of control measures before 
trees are seriously damaged. Studies on DDT-sprayed plantations 
show that no recurrence of spittlebug attack occurred for periods of 
3 to 4 years after spraying. 
