-96- 
Wisecup and Reed (495) in 1938 reported tests made at Sanford, Fla., 
which showed that poisoned baits containing 1, 2.5, or 7 pounds of cube 
per 100 pounds of standard bait (50 lbs. bran, 50 lbs. cottonseed meal, 
1 gal. molasses and water as needed to moisten) were ineffective against 
southern armyworm larvae. 
Yi/bke ( 495 ) in 1938 reported studies on the action of insecticides on 
the alimentary canal of insects. The epithelial cells of larvae that were 
killed 60 to 80 hours after they had ingested rotenone or phenothiasine 
presented no abnormalities definitely attributable to the action of the 
poisons, whereas the arsenicals caused marked disintegration of the epith- 
elial cells, and barium fluosilicate caused the epithelial layer to be 
thrown into characteristic folds, probably as a result of an action of 
barium on the unstriatcd muscle fibers. Woke (496) in 1938 also reported 
the results of experiments to determine the biological disposition of ro- 
tenone after its ingestion using sixth instars reared on turnip plants and 
cut lettuce, Rotenone was fed to the larvae in sandwiches and, after in- 
tervals of time, acetone extracts of the tissues, gut contents, and feces 
were prepared and tested against mosquito larvae for the determination of 
toxicity, Suitable checks were employed. The results showed that the 
larva, after ingesting 5 mg. of rotenone, eliminates all or most of the 
substance with its feces. This result was substantiated by chemical tests. 
Pro de nia lit u £5i (P. ) 
DeBussy (56) in 1922 reported the results of tests of various mater- 
ials on the larvae. This lepidopterous insect is of great importance in 
relation to tobacco culture in Deli, Sumatra. The finely ground root of 
Pert 'j s ellip tic a (toeba) was used as a decoction in water up to 10 gin. per 
100 co.,. yet in no case did it kill more than two out of five half-grown 
caterpillars. 
Dusting or spraying with derris had only slight effect. The dusts 
contained from 0.5 to 2.8 percent of rotenone j the spray, 0.11 percont of 
rotenone. — Van der Vocht (454) in 1936. 
Sonan ( 3 79 ) in 1937 reported that derris dusts were ineffective against 
the gray-streaked moth in Formosa. 
Butac (58) in 1938 reported that in 1936 cotton plants in one of the 
plots at the Philippine Carnival Exposition were dusted with derris-gawgaw 
(50:50, rotenone 1,5 percent), mainly to control the leaf-eating caterpil- 
lars which were abundant on the plants. The dusting was done about 9 a.m. 
Between 2 ar>i •" | ■. :&,» the plants were examined and the insects found were 
collected, especially those affected by the treatment. Sixteen vigorous 
•larvae of ProdenU-'. li tura wore collected and none died. 
Van der Laan (V'.:;) reported in 3 938 that in comparative field tests 
at Deli, Sumatra, in 1-J37 derris dusts containing 1.5 and 2,5 percent of 
rotenone proved inferior to a 5-percent load arsenate dust in protecting 
tobacco against lepidopterous larvae. In experiments against the larvae 
i n ''■■■ : ; ■. ri - dorris-dust mixture containing 3 percent of rotenone gave 
results than a spray of derris powder mixed with water to give a 
rotenon atent of 1 in 10,000, but was less effective than a spray of 
1.5 percont of load arsenate. In laboratory experiments the larvae proved 
almost insensitive to derris dust. 
