CONTROL OF INSECT PESTS McATEE 425 



apple-tree boi-er would be a much more widely known and destructive pest 

 were it not for the constant depletion of their numbers by woodpeckers." 



Relative to the striped species he makes still stron<^er statements. 

 ''Wliile the control effect of parasites and predacious foes on this 

 borer is negligible," he says, " woodpeckers play an important part 

 in holding it in check. * * * In several orchards where counts 

 were made from 50 to 75 per cent of the borers had been de- 

 stroyed. " 1" 



Among the Chrysomelidse or leaf beetles, probably the most noto- 

 rious pest is the potato beetle and it is just the species for which we 

 find recorded the most emphatic statements relating to birds as agents 

 of control. There is on record one case of control in Wisconsin, and 

 seven cases of local extermination occurring in Minnesota, Iowa, 

 Illinois, Massachusetts, Pennsylvania, and South Carolina. There is 

 one instance of local suppression of asparagus beetles by birds occur- 

 ring in New York, one of control of the locust-leaf miner in Mary- 

 land, and four instances of effective depredations upon the elm-leaf 

 beetle in Massachusetts. One writer had the temerity to venture 

 that birds do not eat this beetle, but the cedar bird feeds freely 

 upon it, in two recorded cases at least, exercising notable control of 

 infestations and in two others entirely eliminating them. 



Coming to the family Scarabaeidse, we find that white grubs 

 are the most frequent objects of investigation by economic ento- 

 mologists and we learn also that high rank is invariably given to 

 bird enemies of these pests. Dr. John J. Davis, a specialist on 

 white grubs, gives birds first place among the natural enemies. 

 Of his own observations he says: 



Fields of timothy sod have been literally overturned by crows in their 

 search for grubs, and in some fields the grubs were almost exterminated 

 by them. Crows have often been observed following the plow in infested 

 fields, eagerly picking up every grub that was unearthed." 



Mr. Norman Criddle also writes in favor of the same bird and 

 says that while plowing he has personally observed that fully 90 

 per cent of white grubs exposed were picked up by crows. He is 

 so convinced of the value of birds in controlling white grubs that 

 he recommends that farm practice in Manitoba be planned chiefly 

 with a view of best utilizing the services of birds in destroying- 

 white grubs; a remarkable tribute to the effectiveness of practical 

 economic ornithology. He says : 



Birds are most persistent followers of the plow during their breeding 

 season or while migrating; gulls and terns from IMay 1(J to June 22, and 



"Bull. 88G, U. S. Dept. A>,'r., Oct., 1920, pp. 8-1). 

 1" Hull. 847, U. S. Dept. Agr., August, 11)20, p. 29. 

 "Farmers' lUilI. No. 543, U. S. D.partnient of Ajjriculturo, July, 19K!, p. i:!. 



