PLANTS INSECTICIDAL PROPERTIES. 



17 



Table 5. — Comparative results obtained by spraying Macrosiphum sp. A with 

 alcoholic and benzene extracts derived from " cube" derris, and pyrethrum, 

 and with 40 per cent nicotine sulphate. 



Preparation. 



Aphids sprayed with alcoholic extracts. 



Num- 

 ber of 

 sets. 



Esti- 

 mated 

 num- 

 ber of 

 indi- 

 vid- 

 uals. 



Percentage of aphids 

 dead 'within — i 



6 



hours. 



1 



day. 



2 



days. 



3 

 days. 



Aphids sprayed "with benzene extracts. 



Percentage of aphids 

 dead 'within — l 



6 

 hours. 



days. 



3 



days. 



Num- 

 ber of 

 sets. 



Esti- 

 mated 

 num- 

 ber of 

 indi- 

 vid- 

 uals. 



Extract+water 

 (4+100): 



"Cube" 



Derris 



Pyrethrum. 

 Extract+soap+ 

 water (4+2+ 

 100): 



"Cube" 



Derris 



Pyrethrum. 

 Extract+soap+ 

 water (2+2+ 

 100): 



Pyrethrum. 



Derris 



"Cube".... 

 Extract+soap+ 

 water (1+2+ 

 100): 



"Cube".... 



Derris .. 



Pyrethrum. 

 Extract+soap 

 + water (3/4 

 +2+100): 



Pyrethrum. 



Derris 



"Cube".... 

 Extract+soap 

 +water (1/2 

 +2+100): 



"Cube".... 



Derris 



Pyrethrum. 

 Extract + soap 

 +water (1/3 

 +2+100): 



Derris 



"Cube".... 

 Extract+soap 

 +water (1/4 

 +2+100): 



"Cube".... 



Derris 



Extract+soap 

 + water (1/5 

 + 2+ 100) 



"cube" 



Extract+soap 

 + water (1/6 

 + 2 + 100) 



"cube" 



40 per cent nico- 

 tine sulphate 

 (l/400)+soap 

 + water (2.5 



+2+100) 



40 per cent nico- 

 tine sulphate 

 (l/800)+soap 

 +water (1.25 



+2+100) 



40 per cent nico- 

 tine sulphate 

 (1/1,200) + 

 soap + water 

 (0.8+2+100).. 



500 

 500 

 500 



1,680 

 1,500 

 1.700 



500 

 500 

 500 



2,500 

 2,000 

 2,000 



500 

 500 

 500 



3,000 



2,500 



500 



2,000 

 2,500 



2,500 

 1,000 



1,000 

 1,500 



6 3,000 



90 

 100 

 99 



100 

 99 

 62 



30 

 93 



100 



93 



100 

 100 



95 



"ioo 



100 

 76 



60 



100 

 97 

 40 



62 



97 



3 1,500 91 I 95 97 100 



100 

 90 

 85 



85 



100 



100 



S5 



70 



100 



100 

 50 



89 



100 



100 

 70 



100 



100 

 99 

 85 



100 



500 

 500 

 500 



1,000 



1,000 



500 



500 

 500 



500 

 500 



i Where a test did not continue for 3 days, columns are left blank. 

 60635° —24 3 



