24 
BULLETIN 1204, U. S. DEPARTMENT OE AGRICULTURE. 
present in the yard. By maneuvering the plane through sharp 
climbs, rapid dives, or quick turns, the cabins can be avoided with- 
out difficulty, and dust can be delivered to situations which at first 
seemed utterly out of reach. 
Cuts 62 to 64, inclusive, on Shirley plantation presented special 
problems. (See fig. 19.) A few years ago these fields were the bed 
of a swamp lake, but they were drained and made subject to cul- 
tivation by the canal which now extends through Shirley plantation. 
At that time the undergrowth was all cleared from the fields, but 
many of the cypress trees which were scattered through the lake 
were left standing. At present these cuts contain 49 such trees from 
60 to TO feet tall and growing at very irregular intervals. Cotton is 
Fig. 19. — Oblique view of Shirley Plantation, Cuts 62 to 64, inclusive, taken from 500 feet 
elevation, showing t he difficult Hying problem presented by cotton growing among 
cypress trees. 
grown throughout this area right up to the trunks of the trees. These 
fields were considered the most difficult in the community for air- 
plane dusting. In fact it appeared to everyone except the pilots 
that the treatment of these fields was absolutely out of the question, 
but they volunteered to dust them. The leaf worms developed a fair 
infestation only, but still sufficient to require treatment for control 
on two different occasions. 
ETpon examining the fields carefully the pilots found lanes be- 
tween the trees navigable for airplane operation, and twice dusted 
them in a manner which permitted perfect worm control with the 
use of only about 3 pounds of calcium arsenate per acre at each treat- 
ment. It* was found that most of this cotton could be treated by 
direct blast, and that comparatively little of it must be dusted by 
drift of poison. After watching this performance the writers were 
