-112- 
Fedcral regulations prohibit excessive residues of poison on marketed 
cabbage; therefore, paris green should not be applied after the heads 
begin to form. Derris powder may be used aft or that date or through- 
out the season. There nro no regulations concerning residues of rote- 
none on fruits and vegetables* 
Huckctt (202 ) in 1936 reported insectary tests with pyrcthrum, 
derris, and nicotine. The derris contained 4,5 percent rotcnone and 
16 to 18 percent total extractives. The mortalities of fourth instars 
96 hours after the derris treatment were as follows: 
Spray formula Mortality 
Percent 
Derris powder 2-g- gm«, 90 8 
skim-milk powder 2-h 82.5 
gm., water 500 cc. 
Derris powder 2 gm., 87,5 
skim-milk powder 2\ gm., 74*2 
water 500 cc. 
Derris powder 1-|- gm., 81.7 
skim-milk powder 2-g gm., 65.0 
water 500 cc. 
Checks 10 
10 
Powdered derris root (4.5 percent rotenono, 15 to 18 percent total 
extractives) at strengths Comparable to 4, 3, and 2 pounds of powder per 
100 gallons of water gave higher mortality of the imported cabbrge worm 
than of the Cabbage looper. Huckctt ( 205 ) in 1938 stated that in ex- 
periments on Long Island young and old larva, of Pi oris r^p-A r 
susceptible to derris powder. 
Vnn dcr Laan ( 244 ) and DcBussy ct al. ( 57 ) in 1936 report, d that 
this species is sensitive to derris. 
The Now Jersey Agricultural Experiment Station (293) in 1937 r - 
ported that derris dusts had given satisfactory result inst cabbag 
worms, including this species. 
