- .70 - 
infested. In the one ;;erios applied after heavy infesta- 
tion, the reduction in number of thrips was not as 
satisfactory as in the other tests. The addition of sulfur 
increased the mortality in hot weather, "but apparently 
reduced it in- cooler weather. Since these tosts wore 
conducted on irrigated fields, drought did not seriously 
affect the yield of onions, hut the irrigation had no 
marked effect on the number of thrips. 
"Since the productive parts of this work cover orly 
one soason, 210 final conclusions can bo drawn as to the 
practical effectiveness of sprays containing pure ground 
cube root and a suitable spreader. However, the use of 
such sprays offers promise as a control for onion thrips." 
"Addition of a spreader to cube increased its 
effectiveness, and with a suitable spreader cube was more 
effective than nicotine sulfate." 
Roark (352) in 1938 reviewed the comparative action of derris and 
cube of equal rotenone content on many insects. The results are 
tabulated as follows: 
Insect 
Alabama argillaceae Hbn. , 
cotton leaf worm" 
Comparative Action 
Dusts: 
dorr is > cube 
Reference 
Smith, Clark and Scales 
Ancyli s comptana Froel. , 
strawberry leaf roller 
Anthonomus eugenii Cano, 
pepper weevils 
Anthonomus grandis Boh. , 
boll woevil 
derris -, cube 
derris ^» cube 
cube -> derris 
derris > cube 
derris = oube 
Smith and Scales 
Ohio Agr. Expt. Sta. 
Campbell 
Smith, Clark and Scales 
Smith and Scales 
Aphis rumicis L. , 
Ascia rapao L. , 
cabbage worms 
Dusts, water suspensions, G-insburg and Granett 
and acetone extracts: 
derris > cube 
Dusts; 
derris >• cube 
derris = cube 
Campbell 
List and Sweetman 
