Material 
-lU9- 
Dust used 
per acre 
Worms found — 
Before On On 
dusting j June l6 \ June 19 
Pounds 
Pyrethrum, 0.20 percent 
Pyr.ethrum, 0.50 percent, 
diluted with talc 
Derris (0,7^ percent rotenone) 
Fumber Number Number 
25.7 
9 
r 
16 
.26.1 
6 
5' 
2k 
10.3 
2 
7 
1+ 
White ( UgQ ) in 193^ stated that derris was ineffective against this 
insect. 
Chamberlin and Morrill (6S) in 193& Galled attention to the necessity 
of devising a new method of evaluating insecticides tested against this 
insect. The fifth instar consumes 300 square inches of shade-grown tobac- 
co leaf, or about 12 times as much. as the fourth instar, which in turn 
consumes 5 times as much as the third instar. Chamberlin and Morrill pro- 
posed that the value of the insecticide applied be determined by the ratio 
of the third, fourth, and fifth instars to the total of all instars, 
rather than by the usual method of percentage of kill. According to this 
method, the lower this ratio the more.- efficient the /treatment. Different 
insecticides yielded the following results: 
Insecticide 
'5 parts lead arsenate + 3 parts lime 
1 part paris green + U parts lime 
1 .part "Oaris green + 6 Parts 1 
lme 
1 part derris + 1 part sulfur + 2 parts clay 
Phenothiazine diluted 1:10 
Ratio 
0.091 
.071 
.079 
.381 
.552 
C-underson (172.) ^ n 193^ recommended derris with or without sulfur for 
the control of Protoparce qui nquemaculata (Haw.) and' P. sexta (Johan.) , 
with flour, sulfur, pearl dust, gypsum, or other carrier as diluents for 
derris dust. He said that a 1-percent-rotenone dust was generally strong 
enough for all needs and that derris spray, 5 pounds per 100 gallons, gave 
satisfactory control of the tomato horn worms, 
This insect on tomato may be killed by dusting the plants rather 
heavily with a dust containing 0.75 percent of rotenone, although the 
larger worms are rather difficult to poison. — Crosby, Chupp, and Leiby 
(87) in 1939. 
• 
