THE LEAD-CABLE BOEER IN CALIFORNIA. 



27 



Table 4. — Emergence of beetles of the lead-cable borer from infested sections of 

 wood tlirough poisons, repellents, and varnishes; Los Gatos, Calif., 1918- 

 1920. 



Exper- 

 iment 

 No. 



Repellent used. 



Where applied. 



Number 

 of adults 

 emerged 



in 



treated 



area. 



Number 

 of adults 

 emerged 



in un- 

 treated 



area. 



Total 

 number 

 of adults 

 emerged 



from 

 infested 

 section. 



1 



5 coats No. 38 varnish 



All of infested section 



63 



78 

 48 





63 



2 



4 coats No. 38 varnish 



Four-fifths of infested section.. 



13 

 31 



91 



3 



4 



15 



6 



7 



28 



3 coats No. 38 varnish 



79 



5 coats spar varnish 



All of infested section 



102 



4fi 



102 



do 





11 

 20 

 18 



8 

 18 

 35 



30 



18 



57 



4 coats spar varnish 





74 



3 coats spar varnish 



Three-fourths- of infested sec- 

 tion. 

 do 



73 

 26 



91 



1 heavy coat beef tallow 



34 



9 





do 



53 

 93 



33 



37 



71 



10 



11 



112 



3 coats of water solution of so- 

 dium silicate. 



Heavy coat of lead arsenate 



1 coat white enamel paint 



do 



One-half of infested section 



Three-fourths of infested sec- 

 tion. 



128 



63 

 55 



1 See PI. VIII, Fig. 1. 



2 See PI. IX, Fig. 1. 



Note. — So far as could be determined, none of these materials hindered the emergence of the beetles to 

 any extent. The beef taUow when allowed to soften in the sun suflocated the beetles and prevented their 

 emergence. 



Attaoking Expekiments. 



Arsenate of lead. — Sections of oak and elm were covered thor- 

 oughly with full-strength arsenate of lead paste and placed in indi- 

 vidual lantern globes with beetles. Nineteen out of twenty-five en- 

 tered the sections and showed no effect from the poison. Normal 

 galleries were excavated and eggs laid which hatched into healthy 

 larvae. 



Black paint and one-third creosote. — Four out of six beetles en- 

 tered at once. 



P. <& B. paint. — Numerous entrances made. Beetles were able to 

 walk on surface of paint soon after it was applied. 



Pine tar. — Thoroughly attacked. The surface remained " sticky " 

 for a short time, especially in warm weather. 



Black iron enamel. — Used both straight and mixed with one-third 

 creosote. The beetles attacked and penetrated without trouble. 



White porcelain enamel.— Wino, out of twelve beetles soon entered. 



Creosote. — ^When sections were treated with pure creosote and 

 placed in the lantern-chimney cages the fumes killed the beetles. 

 When these same sections were taken from the chimneys and placed 

 in the open laboratory the beetles attacked them and entered the 

 wood. 



Carholineum. — The beetles react to carbolineum about the same as 

 to creosote. Some died in a few daj^s after being placed in the chim- 

 neys with freshly dipped sections but a few bored into the sections 

 through the carbolineum coat. 



