PLANTS — INSECnCTDAL PROPERTIES. 11 



gants against two species of aphids, sabadilla, pyrethrum, derris, and 

 " cube " were efficient, while hellebore was inefficient. 



Used as decoctions against Aphis spp. A and B, sabadilla, ami- 

 anthium, and hellebore had practically no effect (Aphis sp. A omitted 

 for these three powders) ; but pyrethrum, derris, and " cube " were 

 efficient. Used as hot- water extracts (decoctions filtered) against 

 the same species, pyrethrum had no effect; derris killed 60 per cent 

 within 24 hours, while " cube " killed practically all within the 

 same time. 



Used as an infusion against two other species of aphids, " cube '' 

 was quickly efficient. 



Alcoholic and benzene extracts of various powders. — Reference to 

 Table 4 shows the following: 8 The alcoholic extracts+soap+ water 

 ( 2+4-4- 100) of sabadilla, amianthium, and hellebore were inefficient 

 against Aphis spp. A and B, while those of pyrethrum, derris, and 

 " cube " were efficient. The alcoholic extracts (8+2+100) of the 

 first three powders were also inefficient against Macrosiphum sp. A, 

 while the benzene extracts (8+2+100) of the same powders seemed 

 efficient, although the control mixture evidently killed 50 per cent 

 of them. The nicotine sulphate ( 1/1,200) + soap+water (0.8+2+ 

 100) was efficient, although it killed rather slowly. 



Alcoholic and benzene extracts and nicotine sulphate against 

 Macrosiphum sp. A. — Reference to Table 5 shows the following 

 comparative results obtained by spraying Macrosiphum sp. A : The 

 alcoholic extracts+ water (4+100) of " cube," derris, and pyrethrum 

 were efficient within three days ; " cube " is best and derris is slightly 

 better than pyrethrum. 



The alcoholic extracts+soap+water (4+2+100) of " cube," der- 

 ris, and pyrethrum and nicotine sulphate ( 1/400) + soap+water 

 (2.5+2+100) are about equally toxic; the same extracts (2+2+100) 

 and nicotine sulphate (2.5+2+100) are about equally toxic, but the 

 extract of pyrethrum acts the most slowly; the alcoholic and ben- 

 zene extracts (1+2+100) of "cube" and derris and nicotine sul- 

 phate (2.5+2+100) are equally efficient, but the alcoholic and ben- 

 zene extracts (1+2+100) of pyrethrum are inefficient; the alcoholic 

 extract (3/4+2+100) and the alcoholic and benzene extracts (1/2+ 

 2+100) of " cube," and nicotine sulphate (2.5+2+100) are about 

 equally toxic, while those of derris are less toxic and may be com- 

 pared with nicotine sulphate (1/800) or (1.25+2+100), and those 

 of pyrethrum are far below efficiency ; the alcoholic and benzene 

 extracts (1/3, 1/4, 1/5, and 1/6+2+100) of "cube " and nicotine sul- 

 phate (1.25+2+100) compare favorably in toxicity, while those (1/3 

 and 1/4+2+100) of derris are inefficient. 



Alcoholic extracts and nicotine sulphate against 11 species of 

 aphids. — Reference to Table 6 shows the comparative results ob- 

 tained by spraying 11 species of aphids with alcoholic extracts. In 



8 Id Tables 4 to 8 the expression "alcoholic extract + soap + water (2 + 4 + 100)" 

 means that the extract from 2 pounds of powder was mixed with 4 pounds of fish-oil 

 soap and 100 gallons of water. The expression " Control, alcohol + soap + water 

 (2 + 4 + 100)" means the same amount of alcohol, soap, and water as used in the pre- 

 ceding mixture ; or, in other words, this mixture differs from the preceding only in that 

 it does not contain the dry extract. The expression " 40 per cent nicotine sulphate 

 (1/1,200) + soap + water (0.8 + 2 + 100)" means 1 part by volume or 0.8 pound 

 of nicotine sulphate to 1,200 parts of soap solution (2 pounds to 100 gallons of water). 

 The weight of the nicotine sulphate is merely given so that its cost can be compared with 

 that of the various powders used. 



