PLANTS — INSECTICIDAL PKOPERTTES. 9 



turtium aphids sprayed with nicotine resinate were killed, while the 

 same mixture applied to apple trees was efficient against Aphis pomi. 

 The results obtained with nicotine sulphate are given in Tables 4 to 6. 



CASTOR-BEAN. 



The juice from the leaves and green pods of a castor-bean plant 

 {Ricinus communis) had only a slight effect on bees. The powdered 

 beans and husks, free of oil, killed all the bees tested; but some of 

 this powder, after having been extracted with a 10 per cent solution 

 of sodium chlorid, apparently did not kill any of the bees tested. 

 Several attempts at feeding dough mixed with the powdered beans 

 to roaches failed. The powder had no effect on webworms, but had 

 a slight effect on silkworms, flies, and grasshoppers. 



An alcoholic extract of castor-beans, when reasonably strong and 

 used with soap (No. 511, Table 4), was inefficient against three 

 species of aphids {Aphis spp. A and B, and Macrosiphum sp. A), 

 but when fed to silkworms without the addition of soap it had no 

 effect on these larvse. A benzene extract (No. 520) , when exceedingly 

 strong and used with soap, was efficient against Macrosiphum sp. A, 

 but the control mixture seemed to have killed half the number. 



SAEADILLA. 



Using sabadilla seed {Schoenocaulon officinale), the following 

 results were obtained: The powders (Nos. 56 and 121, oil extracted), 

 used as dusts, were efficient against grasshoppers, roaches, bees 

 (Table 1), silkworms, and webworms, but they had practically no 

 effect on five species of aphids {Aphis rumicis, A. brassicae, A. spp. 

 A and B, and M acrosiphonella sanborni) ; the powder (No. 113, 

 oil not extracted) , used also as a dust, was efficient against silkworms 

 (Table 1), but had practically no effect on the third, fourth (Table 

 2) , and fifth species of the above aphids. 



The powders (Nos. 56 and 113) of sabadilla seed, used as fumi- 

 gants, had only a slight effect on silkworms and webworms, but were 

 efficient against Macrosiphum sp. and My bus persicae (Table 3) 

 and against the one lady-beetle tested. 



The powder (No. 56a) of sabadilla seed, used as a decoction, had 

 no effect on Aphis spp. A and B (Table 3). A soda extract, used asi 

 a spray material, had no effect on nasturtium and cabbage aphids,, 

 but was efficient against grasshoppers, bees, and small webworms. 

 Hot and cold water extracts, used as spray materials, had no effect 

 on nasturtium and cabbage aphids, but were efficient against grass- 

 hoppers, bees, and silkworms. An oil, extracted by petroleum ether 

 and used as a spray material, suspended in water, was efficient, 

 against grasshoppers. Oxalic acid extracts were efficient against 

 silkworms, while oxalic acid, used as a control, had no effect on them, 

 A distillate also had no effect on silkworms. The alcoholic and 

 benzene extracts (Nos. 510 and 519), used with soap (Table 4), were 

 inefficient against three species of aphids {Aphis spp. A and B and 

 Macrosiphum sp. A). The alcoholic extract was efficient but very 

 slow against silkworms. 



HELLEBORE. 



The commercial powder of white false-hellebore {Veratrum album) , 

 used as a dust, was efficient but slow against roaches and silkworms, 



60635 6 — 24 2 



