THE CANADIAN ENTOMOLOGIST 17 



POPULAR AND PRACTICAL ENTOMOLOGY. 



The Plum Curculio in Ontario, Nature and Extent of the 

 Injuries, Conditions Favouring the Insect, and 



Means of Control. 



Part II — Conditions Favouring the Insect. Amount of 

 Damage Done, and Means of Control. 



by l. caesar, guelph, ont. 



(Continued from vol. XLVIII, page 400.) 



As the Curculio winters, in the adult stage, under rubbish or 

 in any good hiding place, and as the better the opportunities for 

 good winter quarters the larger number of beetles that will come 

 safely through the winter, we should naturally expect that orchards 

 or parts of orchards bordering on thick woods, or waste places where 

 long grass, weeds, brush or other rubbish abounds, or orchards that 

 are badly neglected and have an abundance of weeds and rubbish 

 within their own borders, would be worst infested. Such is the 

 case, for, as a rule, in Ontario it is only orchards of this type that do 

 suffer much from the Plum Curculio. 



Amount of the Injury. 



No accurate estimate of the amount of injury has been made 

 for the Province as a whole, but I believe I am right in saying that 

 the fruit in well-cultivated and well-sprayed orchards with clean 

 surroundings suffers only to a very small extent, probably not.more 

 on an average than 1% to at most 5%. On the other hand the loss 

 in neglected orchards or in the parts of well-cared-for orchards im- 

 mediately adjoining ideal winter quarters for the beetle is some- 

 times very great. Under such circumstances apricots, plums and 

 sweet cherries sometimes have almost every fruit stung and de- 

 stroyed, and nearly half of the apples, even on trees that are heavily 

 laden, may be attacked and drop, or if the crop is a light one nearly 

 all may be destroyed. 



The injury in the fall and late summer to peaches and apples 

 seems to vary with the season. This year in the Niagara District 

 in orchards where there is no doubt at all that there were thousands 

 of new beetles in August and September, very little injury was done, 

 only an occasional apple here and there, even in the dirtiest of sur- 



January, 1917 



