-95- ' 
Prodenia eridania (Cram. ), the southern ami, .*orm 
Wisecup (489) compared the relative value of derris and cube, both as 
sprays and as dusts, against the southern armyworm at Sanford, Fla., in 
1933, Small and large larvae were introduced into cages with the follow- 
ing rotenone-containing dusts or sprays on sweetpotato leaves: 
Derris spray, 5 percent of rotenone, 1 part in 200 
Derris dust, 3 percent of rotenone, 0.3 mg. per square inch 
Proprietary cube extract, 1.6 percent of rotenone, 1 part in 200 
Proprietary cube dust, 0,57 percent of rotenone, 0.3 mg. per 
square inch 
The derris, with the greater rotenone- content, appeared somewhat more 
repellent , showing less feeding at the end of 2 days, when all the larvae 
were removed to fresh, untreated food. The end results after a week's time 
were disappointing, as no material had given a kill of over 33 percent; 
however, the derris gave consistently better kills, both as dust and spray, 
indicating that the rotenone must be taken into account when a derris or 
cube product is being recommended, Wisecup ( 491 ) in 1936 reported that 
laboratory tests made at Sanford with 'half-grown larvae indicated in gen- 
eral, that poisoned-bait mixtures consisting of bran, cottonseed meal, or 
corn meal, paris green, cryolite, phenothiazine, or cube, with sirup and 
ground lemons, were not sufficient to overcome the attractiveness ■ 
of the natural green food of those larvae. Paris green and synthetic 
cryolite were much superior to cube, 
Stahl ( 590 ) in 1934 reported that derris dust had a repellent effect. 
The feeding of the armyworm decreased as the concentration of rotenone in 
the dust increased from 0,1 to 3,0 percent, but there was some feeding in 
all cages. 
» 
The United States Department of Agriculture, Bureau of Entomology and 
Plant Quarantine ( 441 ) in 1935 reported that toxicity tests in the labora- 
tory indicated that this insect, vi/hile repelled by derris, was not other- 
wise affected. The Division of Control Investigations, of the Bureau ( 444 ) 
has made many tests with derris and cube dusts. The results may be sum- 
marized as follows: 
Instar 
Rotenone con- 
tent of dust 
Minimum dosage of dust containing 100-per- 
cent mortality in 48 hours. 
Percent 
First 
4.5 
Second 
4.5 
Third 
4.5 
Fourth 
1.0 
Fifth 
5.4 
Micrograms per cm. 2 
90 
120 (21 percent mortality) 
100 (14 percent mortality) 
110 (3 percent mortality) 
125 (20 percent mortality) 
