December, ' 15] CRAIGHEAD: CONTROLLING WOOD-BORING INSECTS 



513 



A NEW MIXTURE FOR CONTROLLING WOOD-BORING 

 INSECTS— SODIUM ARSENATE-KEROSENE EMULSION 



By F. C. Craighead, Branch of Forest Insects, Bureau of Entomology, United 

 States Department of Agriculture 



During the past summer different substances were tried in an 

 effort to kill wood-boring insects, such as Goes (work similiar to 

 Prionoxystus) and Cyllene pidus. In view of the discovery by Dr. 

 A. D. Hopkins that kerosene was effective on the locust borer {Cyllene 

 rohinice), this substance, kerosene emulsion, and carbolineum, were 

 tried but proved of little value in these cases. The kerosene emulsion 

 penetrated the wood and galleries but seldom was in quantity enough 

 to kill the larvae. 



The idea occurred to poison the emulsion so that as it penetrated 

 to the insects and they attempted to bore further, the poisoned wood 

 would kill them. A soluble arsenate, sodium arsenate, was tried 

 mixed with the water to be used in making the emulsion. A 5 to 10 

 per cent arsenical solution was used but it is probable that a much 

 weaker strength will answer. The results were highly successful in 

 all trials. 



The same penetrative properties of the kerosene are retained, 

 quickly soaking in several inches in seasoned wood and in living 

 and seasoned wood through the frass in the larval mines often to a 

 distance of ten to twelve inches. 



Tests made on Goes mines in living trees showed that by painting 

 the holes where the boring dust is exuded this solution quickly ascends 

 along the sides of the burrow and through the frass, killing the larvae 

 in a few days. Hickory logs heavily infested with Cyllene picius 

 were washed with this solution, sponging it on the bark with a piece 

 of cotton. In four days' time all the larvae were killed and many 

 had turned black. Mr. T. E. Snyder tested it on powder post beetles 

 in seasoned hickory and oak. A week to ten days after one application 

 all the larvae were killed. Many were one and one-half to two inches 

 in the' wood. 



As a preventative for wood borers, in construction timber, it has 

 not been tested, but will no doubt give good results where the lumber 

 is not exposed to severe weather conditions. Should the kerosene 

 evaporate, the arsenic would remain deep in the wood unless leached 

 out by contact with water. 



