274 INSECTS 



insects that chew their food and feed openly upon 

 plant tissues, arsenical preparations may be used with 

 good effect. Up to within a few years Paris green was 

 practically the only satisfactory material of that char- 

 acter, and even that could not be used on tender foliage 

 or on conifers without extreme caution. Recently, the 

 manufacture of arsenate of lead has been developed to 

 a point that we have now a satisfactory killing agent 

 that can be safely used at any strength on foliage of 

 any kind. It has the further advantages of remaining 

 well in suspension without constant stirring, and of 

 sticking to the foliage indefinitely after it has once 

 dried. In the garden and greenhouse no other stomach 

 poison should be used and it will be found effective 

 against all caterpillars, saw-fly slugs, beetles and their 

 larvae and generally against insects that actually eat 

 foliage; it is useless against sucking insects such as 

 plant lice, scales, plant bugs and the like. It contains 

 less actual arsenic than Paris green and at least three 

 times as much must be used to obtain the same results. 

 One pound in 10 gallons of water will kill potato beetles 

 and their larvae; i pound in 50 gallons of water will 

 kill slugs and small caterpillars; i pound in 25 gallons 

 of water is a good general strength for ordinary cater- 

 pillars and other similar species. Paris green is perhaps 

 a little more economical in orchard work and can be 

 used at the rate of i pound in 50 gallons of water for 

 potato beetles, i pound in 125 gallons for orchard work 

 and i pound in 150 gallons on sensitive foliage or against 

 young caterpillars. It should never be used on peach or 

 conifers and should be very cautiously used in the 

 garden. It is well to slack one pound of quick-lime 

 with every pound of Paris green to combine all the 

 water-soluble arsenic in the insecticide, especially when 

 used at the greater strengths. 



