THE CANKER-WORM ON SHADE AND FOREST 



TREES. 



At Jacksonville, Illinois. 



At a session of the State Farmers' Institute held in Jackson- 

 ville, 111., February 19 22, 1*)01, information was g-iven me by Mr. 

 H. S. Weston, Principal of the Jacksonville Hig'h School, from 

 which I inferred that the canker-worm had done considerable in- 

 jury to elm-trees in that city the preceding- year, and this sur- 

 mise was supported by additional information sent me February 

 25 by Dr. F. C. Winslow, Superintendent of the State Insane Asy- 

 lum at that place. Mr. Weston kindly promised to watch for the 

 adult insects that spring, and to g-ive me notice if they appeared, 

 and I received from him in consequence the following- letter, dated 

 March 19: 



"I send you by mail specimens of the moth which I suppose 

 is the parent of the worm which has destroyed our fine elms. The 

 warm sun beg-an to bring- them out of the g-round last Sunday, the 

 seventeenth. They make for the nearest tree, and are now to be 

 found hidden away in the crevices of the bark. Whether the 

 moths fly into the trees or crawl up I do not know. At any rate 

 the eg-g-s are deposited on the twig-s, I suppose, where the young- 

 worms hatch just at the time the first foliag-e appears. This they 

 completely destroy when present in sufficient numbers." 



The insects sent were the male moth of the canker-worm, and 

 in my acknowledg-ment of March 22 I advised Mr. Weston that 

 the trees mig-ht be protected at that season by surrounding- the 

 trunks with an adhesive l)and which should prevent the females 

 from ascending" the trees, but that if this were not done the only 

 alternative would be spraying- the foliag-e of the trees with arsen- 

 ical poisons in May, after all the eg-g-s were hatched. This advice 

 being- published in the local papers, many citizens applied a band 

 of g-as-tar to the trunks of their trees, after smoothing- away 

 the bark in a belt about twelve inches wide and about five feet 

 from the g-round. This was done in most cases late in March or 



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