66 ANM'AI. REPORTS OF DEPARTMENT OF 
bad been made. The arsenic In the soils bad b more Injurious effect 01 
beans than on cotton and corn. The germination was fair but many plants 
died "ii the plots receiving h»<>. 800, and 1,600 pounds of < -;i i< i n i j i arsenate per 
acre, and on three of the Beven soils soybeans were b complete failure where 
1,000 pounds of calcium arsenate had been applied. The effect ot 
quantities of calcium arsenate varied considerably with the different s«>ii types. 
<>n the four types i i s< U where field tests with cotton were conducted, only the 
Ruston soil :n Poplarville, Miss., showed noticeable Injury by applicatloi 
200 pounds or more of calcium arsenate. 
COTTON FLEA HOPPER 
Dusting with sulphur for control <>f" the cotton flea hopper continued to 
give profitable returns. Although weather conditions .-it Port Lavaca, Tex., 
during 1935 were very unfavorable and too much rain hindered the dusting 
program, i<> Large-scale sulphur-dusting experiments averaging 84.1 treated 
acres per experiment made an average gain of 167.5 pounds of seed cotton 
and a net profit of $4.75 per acre. A mixture of ]<» percent of i 
niid mi percent of sulphur gave a higher kill of the flea hopper than dia 
sulphur alone an outstanding result of the year. The average gain from 
three 1-acre plots dusted with two applications of 10-percent paris green- 
Bulphur was 220 pounds of seed cotton per acre; the cost of treatment was 
$1.92 and the value of the increased production was $9.66, Leaving a net profit 
Of $7.74 per acre. A few preliminary experiments with a mixture of 20 percent 
Of Calcium arsenate and 80 percent of snlphnr also showed to good advantage 
over sulphur alone. One held dusted only twice with this mixture produced 
a gain of 14.^ pounds of seed cotton per acre, as compared to a gain of 134 
pounds from a comparable held dusted four times with sulphur alone. These 
held experiments are in line with results obtained during the last :> years 
in cage toxicity tests in showing that while sulphur is very effective against 
the cotton ilea hopper nymph, arsenicals are more effective against the adult. 
During the spring of 1936 approximately 20 percent more ilea hoppers emerged 
in the hibernation cages than during the 2 preceding years. The emergence 
was .'! weeks later this year than in 1935 and. as many wild host plants were 
then present, the Ilea hopper infestation in cotton was later and lighter than 
usual. During April. May. and June 1936, 1,360 Ilea hoppers were caught on 
12 screen traps located in different parts of Calhoun County. Tex., as compared 
to 3,814 during the same period of 1935, 7.4i':{ in 1934, and 6,404 in 1933. A- in 
1934, nine generations of the cotton ilea hopper occurred at Port Lavaca in 
1935. in June 1936 two egg parasites of the cotton flea hopper were discovered. 
one species, Anaphes anomocerus Gir., had previously been reported as an egg 
parasite of another mirid, occurring on alfalfa in Utah, hut the more abundant 
parasite is a new species of Erythmelus. 
BOLLWORM 
During the summer of 1935 there was a serious outbreak of bollworms in 
(he cotton fields Of the Mack lands and river bottoms of northeastern Texas. 
Thousands of acres of cotton were dusted with calcium arsenate and other 
arsenicals by various types of dusting machines. Including a Dumber of airplane 
dusters, it was Impossible to determine the amount of damage caused by 
bollworms, a- most of the cotton fields were at the same time seriously Infested 
villi COtton leaf worms, holl weevils, colli. ii flea hoppers, and other insects that 
were causing damage, in a -eric- of test- with different methods of control 
none was ion ii< I bo profitable as the application of calcium arsenate at i or 5-day 
Lntervals from the time the worm- made their appearance on cotton, the appli- 
cations being continued a- Long as the worms were present. The held- receiv- 
ing tin- treatment were dusted with calcium arsenate on an average of nine 
time-. The Dumber of applications ranged from r» | ( . p_\ depending on the 
abundance of the bollworms cotton ami also on the Dumber of time- the 
calcium arsenate was washed off by rains. The plots receiving this treatment 
made an average gain of L50 pounds of seed cotton, or a profit of $15.46 per 
During the fall of 1935 •■' disease that was widespread amoog the boll- 
Ion of Texas Killed most of them, and it is thought that those 
entei oil to pupate must have died there, a- no moths emerged in the 
hibernal ion cages during t be spring of It 
0*A< 
