581 
more or less, but the form which assemble on the roots and 
there produces gall-like swellings is much more difficult to 
extirpate. Every part of the tree which is not blight-proof is 
liable to be attacked, but the roots are now protected by grafting 
or a resistant stock of which the best is the Northern Spy. The 
injury to the tree is caused by the sucking of the sap, which de- 
prives it of nourishment, and by poisoning of the plants, shown by 
the galls on the roots. The damage is particularly serious in the 
case of young trees and nursery stock. The mature bark unless 
bruised or cut is less penetrable, but the bark on the tender growth 
is easily attacked, hence the blight being more particularly severe 
in young apple orchards. Some varieties are more liable to be 
attacked than others, viz., the Jonathan, Reinette du Canada, 
Cleopatra. 
Among the many remedies used for the destruction of the woolly 
aphis are Nos. 6, 7, 8, 12, 14, or 20, also kerosene (see p. 526). 
A fortnight after Nos. 10 or 14. The use of blight-proof stock, 
and No. 9 have been proved satisfactory. A jet of water ejected 
under pressure from a force pump or in suburban gardens from the 
water service pipe, when the pressure is good, is an efficacious way 
of dealing with the pest, provided the treatment be frequently 
applied, 7.e., every two or three weeks in the summer time. These 
jets of water under high pressure dislodge the woolly aphis, as well 
as other aphides, mites, red spiders, clean the tree without destroy- 
ing the friendly natural enemies of our orchard pests, and give the 
tree a refreshing spray, without 
having any of the injurious results 
of poisonous and caustic sprays. 
Natural Enemies.—The woolly 
aphis has very few known natural 
enemies. The larve of some species 
of lace-winged flies (Chrysopide) 
have often been noticed feeding 
upon this pest, and the ladybird 
(Leis conformis) and (Coccinella 
repanda) have been known to al- 
most rid whole orchards of it. 
Buack APHIS OF THE PEACH 
(Aphis persica niger). 
This aphis has proven very 
destructive to the peach trees of 
this State, and as it exists in two 
New ee ee with forms, aerial and subterranean, 
similar to the woolly aphis, its 
control is subject to all the perplexities of the latter aphis. It 
attacks the leaves when they are pushing in the spring, and it 
