The Canadian Horticulturist. 



269 



THE BLACK APHIS OF THE PEACH. 



growers of the peach, both nurserymen and 

 irdists, have reason to be on the lookout for 

 lew pest. It is very common in the peach 

 ions of New Jersey, Maryland, Delaware and 

 ;inia, and is said to come next to the yellows 

 destructiveness, having ruined in one nursery 

 some 100,000 young trees in about three 

 weeks. It has been introduced into Niagara 

 County, State of New York, on trees im- 

 ported from Delaware. This aphis feeds on 

 the roots and swelling buds and young 

 twigs and leaves. Often it does not appear 

 in any considerable number on the tree, but 

 the roots, stunting the trees, and causing the 

 turn a sickly, yellowish-green color, 

 has two forms : one without wings, which is 

 the more common form, the other with four wings. 

 The one without wings is nearly one-tenth of an inch long; color, a dark shining 

 brownish-black, parts of the legs yellowish. The winged form is more slender 

 and a little longer ; the antennae are longer, and the wings transparent. All of 

 these that have as yet been found are females, neither males nor eggs discovered. 

 These females of both forms give birth to other females, which in turn give birth 

 to more females, and thus keep up a succession of female breeders. Doubtless 

 there is a period in their life history when males appear, but how many genera- 

 tions of female breeders intervene is not yet known. It is only the winged form 

 that works on the roots, there they multiply and are to be found at all seasons, 

 but some of them come out when the buds begin to swell, and by means of 

 their wings fly to other trees and to neighboring orchards. 



This pest in both forms feeds by suction, being provided with a beak and 

 fine bristles or sela; with which it penetrates the tissues and sucks up the sap. 

 Therefore they cannot be killed by spraying with poisons that must be taken 



into the alimentary system. Spraying with kero- 

 sene emulsion, diluted with ten parts of rain water, 

 or a strong decoction of tobacco, say five pounds 

 of stems steeped in three gallons of water for three 

 hours, diluted to seven gallons, will kill those on 

 the branches. Spraying should be done early in 

 the season, for the aphis begins its work as soon 

 as the buds swell. But this will not destroy those 

 on the roots. No experiments have come to the 

 writer's knowledge made for the purpose of killing 

 those on the roots. It is suggested by Mr. Sling- 



Fk 



o(j9. — Wingless Female 

 Magnified. 



