58 



THE EEPOET OF THE ENTOMOLOGICAL SOCIETY. No. 36 



NOTES ON FRUIT TREE SCOLYTIDS. 

 By J. M. SwAiNE^ Macdonald College, Que. 



There are three species of scolytid beetles occasionally injurious in parts ol* 

 this country to orchard trees. Two of them, Eccaptogaster rugulosus, Ratz., and 

 Phlceotribus liminaris, Harris, have recently caused considerable uneasiness in 

 certain fruit districts of Ontario, and the third, Xyleborus dispar, Fabr., has been 

 a well-known pest of Nova Scotian apple orchards for some years. 



Apparently these insects are not serious pests in Quebec Province. X. dispar 

 is found here commonly in Betula lutea and other forest trees, but I have not yet 

 taken it in Quebec from orchard trees. The first two species are at least rare 

 in the Montreal district. 



Inquiries have come to this Department recently for an easy method of sep- 

 arating these three forms, and the following notes are to that end. 



The Shot-hole Borer, Xylehoriis dispar, cuts round, black tunnels deep into 

 the wood; in small branches or stems one division of the tunnels partially girdles 



Fig. 1. Tunnels of E. rugulosus in peach: (e) entrance hole; (e.t.) egg tunnel cut by- 

 adult ; (l.y.) larval gallery ending in p.c. — the pupal cell. 



the wood. The eggs are laid free in the galleries early in June, and the larvae 

 feed upon the fungus which grows upon the tunnel walls, and gives the dark 

 stain just referred to. The larvae do not enlarge the tunnels, and emerge when 

 matured, through the entrance hole cut by the mother insect. In the other two 

 species each individual beetle, when ready to emerge, cuts a separate hole through 

 the bark. 



This species breeds in various forest trees and in fruit trees. Of the latter 

 it apparently prefers the apple, and does harm chiefly to the young stock. The 

 remedies aim to repel the tunnel-cutting females, which do the entire damage, or 

 to destroy the food-fungus and the brood within the tunnels. Good results have 

 been obtained in Nova Scotia from the use of a wash made of 3 gallons of water, 

 1 gallon of soft soap, and half a pint of crude carbolic acid. This wash is ap- 

 plied several times while the beetles are prevalent, the first application being made 

 about the first of June. Badly infested trees should be burned, and those still 

 of value may be treated with carbolic wash, and should receive good cultivation 

 and plenty of fertilizer. Trees in good health are less liable to attack. Diseased 



