-1^7- 
Baker and Quest el" (21) in 1939 reported that at Toledo, Ohio, derris } 
powder (rotenone k percent) at U pounds pel* 100 gallons of water plus Area 
kap at 1": 2,000 reduced the "borers as follows: ' In 1937, 9*4, U. percent on 
ears, 9L9 percent on plants; in 1938, 92.S percent on ears, 89.3 percent 1 
on plants. Derris dusts were tried with the following results: 
"KeoTictlon of borers in — 
Year ; Material ; ' ' Bars "' : , Plants 
Percent Percent 
1937 Bancroft clay + derris 
(rotenone 0.8 percent) 
+ Areskap 1:3000 69.7 63. 
1938 Bentonite + derris 
(rotenone 1 percent) * 6l.O 59.4 
The authors concluded that, in general, the sprays were more effective 
than the dusts. Derris and the fluorine compounds gave excellent protectio: 
when used as sprays in a standard-treatment schedule of four applications' 
at !>-day intervals, starting immediately after the first hatching of eggs. 
The fluorine compounds injured the plants, however, which makes their use 
undesirable unless some means can he devised to eliminate burning. 
Pyrausta salentialis (Snell.) 
The Federated Malay States Department of Agriculture ( 122 ) in 1933 
stated that experiments for the control of the larvae, which "bore into corn 
stalks, have been laid down, consisting essentially of a varying number of 
applications of the extract of tuba root. 
Saturniidae ' 
Cricula trifenestrata (Heifer) 
Dusts containing as little as 0.25 percent of rotenone killed all 
larvae within 3 to h days. — Van der Vecht ( jjjjf ) in 1936. 
Schoenobiidae 
« 
Schoenobius bipunctiferus (Walk.) 
The Federated Malay States Department of Agriculture (119) in 1920 
sprayed derris extract for the control of this species, with uncertain 
results. 
Jack ( 2l6 ) in 1923 wrote that the juice extracted from Derris elliptic* 
was most effective in combating this species attacking rice. 
