48 ANNUAL BLBPOBTS OF DEPAB I M EOT OF A(;iilCULTrKE, 1935 
The fourth annua] application of calcium arsenate to the soil, at the rate 
of -KM) pounds per acre, was applied on a plot at Tallulah, making a total 
of 1,600 pounds applied. The average yield of Beed cotton per acre for 
from the treated plot was 1,701 pounds and from the untreated check plot, 
1,744 pounds, a difference of 43 pounds or 2.5 percent in 1931 and 1982 the 
treated plot yielded more than the untreated plot, while in 1933 and 1934 the 
plot with the calcium arsenate yielded less. These yield records indicate that 
excessive applications of calcium arsenate do not affect the yi< !OttOD 
on the particular type of alluvial sandy loam soil near Tallulah. During 
veivetheans grew normally on the treated plot hut soybeans 
died. 
That a holiweevil may occasionally live for an entire year was again dem- 
onstrated at Tallulah in 1934. one weevil placed in a hibernation 
November 16, 1933, was last observed ::•;<> days later on November 10, 1934. 
Another weevil placed in a hibernation cage on November 1, 1933. was ofe 
377 days later on November 12, 1934. The weevils used in these tests were 
given special care during the summer of 1!»34 and were again placed in hiberna- 
tion cages in the fall. They died during the following winter. 
PINK BOLLWORM 
Extensive releases of the parasites Exeristes roborator Fab. and. Microh 
brcvicornis Wesm. indicate they are not adapted to conditions in Texas and 
Mexico where the pink bollworm occurs. Although these Insects readily par- 
asitize the pink bollworm, IJ. roborator emerges too early in the spring and M. 
brcvicornis does not survive the winters. Four other specie's of parasites are 
now being bred for releasing as follows: Micvobracon kirkpatricki Wall 
ceived from Egypt where it had been imported from east-central Africa; 
Elatmus sp., introduced from Egypt; Microbracon mellitor Say. introduced 
from Hawaii; and Ch clonus blackburni Busck, intnxlueed from Hawaii. 
Studies are under way to determine the resistance of different variety 
cotton to pink bollworm attack, the characters causing resistance 1 , and the 
influence of different cultural and climatic factors on these characters. < I 
vations at Tlahualilo, Durango, Mexico, indicate that the pink bollworm has a 
preference for bolls between the ages of 30 and 41 days from the di te ^f 
blooming. As the infestation becomes heavier the preference is le<s marked 
and bolls of all ages are infested. Studies of pink bollworm damage in the 
vicinity of Tlahualilo showed that the reduction in yield of seed cotton, the 
reduction in grade of lint, and the damage to the seed caused a loss io the 
crop of $22.97 per acre. 
COTTON FLEA HOPPER 
The results of tests at Port Lavaca, Tex., during two seasons show that the 
average Increase in so(Ml cotton per acre in the plots treated for the cotton tlea 
hopper was 230 pounds with a net profit of $!».7r> in 1933 and 806 pounds with 
a net profil <>f $12.66 in 1!'.", I. In a series of 336 cage tests in which 15.566 
cotton flea hoppers were used in the summer of 1934 for testing 35 Insect! 
the befit results were Obtained from a mixture of 1 part of pans green with 
10 parts of sulphur. The heavy migration of flea hoppers to cotton occurred 
during the flrsl week of June in 1935, which was approximately :'. weeks later 
than in 1934. Sticky screens QSed to catch Ilea hoppers si i | there is 
considerable movement of the hoppers in the spring at leasl 24 feet in the air. 
and thai more are collected on the leeward side <ii' the screen. Ninety-nim 
eight-tenths percent of the cotton Ilea hoppers emerged from croton, the principal 
overwintering host plant. Other plants from which the other 0.2 percenl i^\' the 
hoppers emerged were cotton bitterweed, cocklebur, and bloodweed. Nine gen- 
erations of hoppers occurred at Pert Lavaca during 1934. 
APHIDS ATTACKING COTTON ROOTS 
c rtain aphids attacking roots <>f cotton kill or seriously injure y< ung i ' 
particularly along tic Atlantic Coastal Plain, ami stud begun at 
Florence, s. c. to develop control measures for them, especially I 
I in <i iris Forbes, Triftdaphis phaseoli Pass., and Rhopalosiphutn sp. The 
flrsi species causes BerioUS injury to young cotton in North Carolina. South 
Carolina, Georgia, and Virginia, while the other two species have been reported 
only from the Oarolinas. 
