PLANTS — INSECTICIDAL PROPERTIES. 23 



a slight effect on catalpa caterpillars, while an alcoholic extract 

 from it had no effect on small webworms and tulip-tree aphids. 



A water extract of lancepod (Lonchocarpus sp.) had no effect on 

 silkworms. 



The powder from the common matrimony- vine (Lycium halirm 'fo- 

 lium), used as a dust, affected roaches considerably, but tent cater- 

 pillars only slightly; and used as a stomach poison, it had a consid- 

 erable effect on grasshoppers. The water extract did not affect bees. 



A commercial powder containing Madhuca sp. seeds was tested 

 and found efficient but slow against silkworms, although within 48 

 hours it killed only about 35 per cent of the Aphis spp. A and B 

 tested. A decoction of the powder had only a slight effect on the 

 same species of aphids. 



A water extract of the wood of moetoepoe (see footnote on p. 26) 

 proved to be efficient, while a water extract of the leaves was found 

 to be inefficient against silkworms. 



A water extract of the leaves of necoetae (see footnote on p. 26) 

 killed silkworms very slowly. 



The powder from the leaves and stems of the common oleander 

 (Nerium oleander) and a decoction from this powder had no effect 

 on aphids (Macrosiphum sp. B). 



An infusion and a decoction of the leaves of tree tobacco 

 (Nicotiana glauca) with soap (1 pound to 50 gallons of water) had 

 only a very slight effect on nasturtium aphids, while the powdered 

 leaves had no apparent effect on them. (An analysis of some of 

 the leaves, made by a chemist of a tobacco by-products company, 

 showed that the nicotine content, upon a moisture-free basis, 

 amounted to only 0.18 of 1 per cent) . 



The hot and cold water extracts of the bark and leaves of 

 Pan-gium edule were found to be inefficient against tent caterpillars. 

 The extracts from the bark appeared a little better than those from 

 the leaves. 



Neither the exhalation nor decoction from the green leaves of 

 Pongam pinnafa had any effect on nasturtium aphids. 



A hot-water extract from the green tops of the American elder 

 (Samoucus canadensis) had no effect on silkworms, webworms, or 

 rose aphids. 



A powder and a decoction from the whitetop-aster (Sericocarpus 

 asteroides) had no effect on the aphids (Macrosiphum sp. B) tested. 



The water extract of the horsenettle (Solanum carolinense) had 

 no effect against small webworms and small catalpa caterpillars. 

 The powder, used as a fumigant, had no effect, against small catalpa 

 caterpillars ; used as a stomach poison, it had no effect against silk- 

 worms and webworms, but had a slight effect on grasshoppers ; and 

 used as a dust, it had a slight effect on tent caterpillars and roaches. 



The powder from sleepy grass (Stipa viriclula), used as a dust, 

 had no effect on tent caterpillars, but had a slight effect on roaches. 



A water extract of the bark of suma rubra (see footnote on p. 26) 

 had a slight effect against silkworms. 



A water extract of tssikoena (see footnote on p. 26) had a slight 

 effect against silkworms. 



The powdered roots of Veratrum calif ornicum had no effect on 

 grasshoppers. 



