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winter is as a wingless viviparous form which hides in. 

 cracks in the bark, in the canker-like wounds, or in the galls 

 on roots. There appears to be a migration of individuals 

 from the portions of the tree above ground to the roots at 

 the approach of winter and a return migration from below 

 to the branches in the spring. 



Natural Enemies. There are not many natural enemies 

 that do much good in checking the increase of this pest. 

 Possibly the woolly excretions and oily globules that surround 

 the . insect protect it from the various foes which attack 

 unprotected plant lice. 



The larvae of Lady Birds (Coccinellida) devour them, as 

 also do the adult Lady Birds. Larvaa of several species of 

 Hover Flies (Syrphida) also feed upon them, but not to the 

 same extent as upon other plant lice. Lace Wing Flies and 

 Ichneumon Flies are seldom found attacking them. Small 

 dipterous larvae of the genus Pipiza feed on the subterranean 

 form. Perhaps the Tits (Parid-a) (See Leaflet No. 43*) do 

 most good in keeping down this pest. These little birds, 

 especially the Blue Tit, do inestimable good by devouring 

 woolly aphis and other pests all the year round, and should 

 be protected in every orchard. 



Methods of Prevention and Remedies. (1) Woolly 

 aphis is especially prevalent in neglected orchards where 

 the trees are close together and where their trunks are 

 covered with lichens and moss. To clean the trees and 

 destroy the hibernating females a winter wash should be used. 

 This may be the simple alkaline wash composed of caustic 

 soda, 2-2 lb., and water, 10 gallons, or it may be one of the 

 more efficient Woburn washes (See Leaflet No. 70*). Lime 

 or lime sulphur winter washes have also been found useful, 

 but they are naturally less effective than the more caustic 

 fluids. 



(2) Any portion of a tree which has been wounded, as 

 for instance, by pruning, is specially liable to an attack by 

 woolly aphis. If large branches have been removed the cut 

 surface should always be dressed, Stockholm tar being an 

 excellent dressing for this purpose. 



(3) Methylated spirit brushed well into the affected 

 portions of trunk or branches is the most successful 

 treatment for young trees or when an attack first manifests 

 itself in an orchard. Owing to the rapidity with which 

 methylated spirit evaporates and its consequent expense, 

 paraffin or petrol is sometimes substituted for the spirit, 

 but where the trees are young and the bark thin, this may 

 lead to injury. A wide range of compounds containing' 

 linseed oil, Stockholm tar, shellac and other substances have* 

 also been invented for brushing on to the affected portions 



* Obtainable from the Ministry. 



