20 ANNUAL BEPORTS OB DEPARTMENT OP AGRICULTURE, 1939 
with Miiall gypsy moth infestations that occur on both Bides of the 
international line at Calais, Maine and St. Stephen, New Brunswick. 
In July L938; assembling cages used for attracting male gypsy 
moths were set up as follows: 2,097 in 32 towns immediately sur- 
rounding the infested area in Pennsylvania (these were put out and 
patrolled by Bureau employees); 498 in 17 town.- in New Jersey, sur- 
rounding tin- location where the gypsy moth was last found in that 
State and along the New Jersey, Pennsylvai ia, and New York State 
lines. These were put up and patrolled by State employees. In New 
York 1,476 were placed in 28 town- between the Hudson River and 
the New Jersey and Pennsylvania Lines. They were put up and 
patrolled by Stan- and Bureau employees. From the total, 7. (, 71 
cages, 23 male moth- were caught al 7 cages in 6 towns in Pennsyl- 
vania, and at 1 cage in a town in Ulster County. N. Y. The cages in 
Pennsylvania were all in towns that had been infested previously. 
Since that time the surrounding area h scouted. Five .-mall 
infestations have been found and treated, and in the other town no 
infestation was discovered. In New York scouting covering an area 
of approximately '2 miles surrounding the cage failed t<> indicate any 
infestation. During July 1938 material •■ ired for use in 
charging assembling cages in the summer of L939; v .<u:> charges were 
obtained and held in cool storage (35°-40° F.). 
During the same month an attempt was made to determine the 
feasibility of estimating defoliation by using an autogiro. Territory 
surveyed in several counties and the degree of infestation noted 
on topographical quadrangles. This method appears to give suffi- 
cient promise to warrant its continuance on a larger scale in the 
future. In the summer of 1937 the acreage defoliated was the high- 
est ever recorded, airirreo-atino: 608,760 acres. In July 1938, after the 
records taken by ground and autogiro observation were combmed, the 
total aggregated 393,613 acres. There was a large decrease in Massa- 
chusetts and some decrease in New Hampshire and Maine. Moderate 
increases in acreage occurred in Vermont, Rhode Esland, and Con- 
necticut. No defoliation was recorded in New York, New Jersey, or 
Pennsylvania. 
In continuation of work inaugurated in 1936 relative to studying 
possibilit ies of autogiro use in gypsy moth control, an aircraft of this 
type was purchased and equipped with insecticide-distributing appa- 
ratus of a design resulting from these studies. This equipment was 
used in dune L939. Lead arsenate and fish oil, which were carried in 
separate storage compartments in the giro, were mixed a- they were 
forced fr<»m the machine. One hundred acre- of woodland were 
sprayed. Preliminary results appear to be satisfactory. These must 
he checked after the foliage is down. The distribution ^\' the poison 
on the foliage was more uniform than has been noted previously with 
insecticides released Prom airplanes. It was evident that the equip- 
ment must he improved in order that all the poison released will he 
mixed with the fish oil, and work along this line is being continued. 
Wind dispersion of small caterpillars of the moth is the 
greatest danger t<» the maintenance of the barrier zone. For a num- 
ber of years records have been taken in and near it covering the 
temperature and the direction and velocity of the wind during the 
period when the caterpillar- are small en O Ugh to he blown to new 
