Marcli, 1914- 



THE CANADIAN HORTICULTURIST 



59 



Orchard Aphids and Their Control* 



Prof. W. H. Brittain, B.S.A., Provincial Entomologist, Truro, N.S. 



IX taking into consideration the most 

 economical and effective method to 

 control any insect, we cannot unfor- 

 tunately, confine our attention to that 

 pest alone, for many other factors inter- 

 vene to influence our results. It fre- 

 quently happens that the time to spray 

 for some insect pest coincides with the 

 time to spray for some fungous disease, 

 so that it is often possible by combining 

 \arious sprays, to make one operation 

 take the place of two or even of three. 

 This is true of the aphids in that the 

 most important aphis sprays coincide 

 with important sprays for other insect 

 [jests and fungus diseases, and it is im- 

 portant to remember at this point in con- 

 sidering how we can best reduce the 

 cost of keeping the orchard free from 

 pests. We must also remember that pro- 

 per pruning, careful thinning, adequate 

 cultivation, the judicious use of cover 

 crops and fertilizers with thorough and 

 timely spraying are all factors in the 

 production of better fruit, and none must 

 be neglected if our work is to prove pro- 

 fitable. In taking up this subject, I 

 realize that you are already thoroughly 

 acquainted with the apfiearance and life 

 history of the different orchard aphids, 

 and that you are only interested in hear- 

 ing of some way to kill them. I will, 

 therefore, only deal very briefly with the 

 former side of the subject, confining my 



•Extract from an address delivered at the 

 annual convention last January of the Nova 



Scotia Fruit (irowers' Association. 



remarks very largely to control methods. 



Three species of aphids are commonly 

 found in orchards: First, Green Apple 

 .\phis; second. Rosy Apple Aphis; third, 

 Woolly Apple .'Vphis. 



The first is by far the most common 

 species in Nova Scotia. All of you arc 

 familiar with the small, oval black shiny 

 eggs of this insect, found upon the twigs 

 of the last year's growth during fall and 

 winter. These eggs begin to hatch early 

 in spring, and by the time the leaf buds 

 are showing green most of the aphids 

 have emerged. The tirjie of hatching 

 usually extends over a period of several 

 weeks. The newly hatched aphids are 

 all wingless females that give birth to 

 young without the intervention of the 

 males. A small percentage of the second 

 generation give rise to winged females, 

 which fly to other trees and establish 

 colonies there. The aphids breed con- 

 tinuously throughout the season, some 

 being winged and others, again, wingless. 

 Toward fall true males and females are 

 produced that pair in the ordinary way ; 

 the true females subsequently depositing 

 their eggs upon the twigs. 



The life-history of the Rosy Aphis is 

 similar to that of the green apple aphis. 

 The eggs are laid on the apple, though 

 not nearly so abundantly as in the case 

 of the previous species. The newly 

 hatched young are dark green in color, 

 but later reddish and brownish forms 

 are produced. During the summer the 



aphids migrate to some unknown food 

 plant, returning in the fall to deposit 

 their eggs. , 



The Woolly Apple aphid is in some 

 countries the worst pest of all, owing 

 largely to the fact that it may attack 

 both roots and tops. It is very different 

 in its habits from the two preceding spe- 

 cies, for whereas they are leaf eaters, 

 this species feeds for the most part upon 

 the tender bark of roots or stems. On 

 the roots they form gall-like swellings, 

 and may not be detected until the tree 

 is seriously injured. The chief source of 

 the lice found upon the trees in spring 

 is those that migrate from the roots and 

 those which have remained concealed up- 

 on the trunk of the tree in cracks and 

 crevices of the bark. In spring and early 

 summer they will be found abundant 

 around wounds in the bark or upon 

 stumps of limbs that have been cut back, 

 or in similar locations. Later in the sea- 

 son they are found farther out on the 

 branches, the small limbs, twigs, or 

 leaves being often completely encrusted 

 with the insects. The aphids have an 

 irritating or poisonous effect upon the 

 b^rk, their work causing open cankers 

 upon the twigs. Small galls also result 

 in some cases. 



Probably the most valuable aphidiscide 

 that has been developed in recent years 

 is a preparation of Nicotine Sulphate, 

 called Black Leaf 40, manufactured by 

 the Kentucky Tobacco Product Company 

 of Louisville, Ky. 



I do not wish to enter into the ques- 

 tion of spr;iying for the apple scab, but if 



The Exhibit of Ontario Fruit which carried off the Firit aad SeconJ Prizes in the das* for Five Boxes, at the Canada Land and Apple 

 Show, held in Winnipeg last October. This was the only Open Competition for Apples. British Columbia was Third 



