PESTS 63 



crevices of the bark, etc. ; (2) occasionally in the 

 egg stage, on the bark near the base of the stem ; 

 (3) as an adult, living below ground on the roots. 

 In spring, the eggs give rise to larvae, which, 

 when mature, form the mother-queens, and these 

 produce viviparously the woolly insect familiar in 

 summer. Active adults also exist in summer under- 

 ground, and these also may migrate spasmodically to 

 the trunk and branches. 



Treatinciit. — The pest cannot generally be extirpated 

 by confining the treatment to those portions of the 

 tree which are above ground. The trees should be 

 thoroughly sprayed in winter with one of the caustic 

 emulsions, and, before April, carbon disulphide should 

 be injected into the ground as described on p. 24, 

 or the surface soil should be removed, and the roots 

 wetted with one of the above-mentioned caustic 

 emulsions. 



In summer, if the aphis appears on the trunks of 

 trees which are old, these can be scrubbed with a 

 hard brush, using a weak paraffin emulsion, such as 

 \6d, or, in the case of younger trees, and also for 

 branch treatment, a similar emulsion may be sprayed 

 on to them, but for this to be effective, it must be 

 applied with considerable force, more than can be 

 attained with a knapsack sprayer. An "Abol" 

 sprayer, set so that a jet of liquid hits the woolly 

 patches, will answer the purpose. Undiluted paraffin 

 oil of the best quality (such as White Rose), applied 

 in the form of a fine spray, is very effective, and it 

 rarely causes much damage to the leaves, but solar 

 distillate or petrol must not be used (see p. 43). If 



