DISEASES OF THE APPLE TREE ] 279 



results in much deformation of the leaf which rolls 

 up or curls irregularly and develops protuberances or 

 blisters of a reddish brown colour. Dusting with preci- 

 pitated sulphur containing nicotine is a good remedy 

 against these insects when the tree is in leaf, and 

 whitewashing heavily with lime the whole tree, parti- 

 cularly the tips of the branches, in winter, is also a 

 cheap remedy of great efficacy. 



The woolly Aphis, Sckizoneura lanigera Hausm., 

 is now a frequent cause of trouble in our apple orchards, 

 but our local apples seem to be much less liable to 

 its attacks than most of the sorts newly introduced. 

 The insect attacks the twigs, the branches, the stem 

 and also the roots just below the surface of the ground. 

 The wingless insect is about i| m.m. long, disposed 

 in rows or lines, chiefly along the undersurface of the 

 twig. Its colour is yellowish or reddish, sometimes 

 reddish brown ; the antennae are very short and of 

 a pale yellow colour. The winged insect is of a 

 shining black colour, with a chocolate brown abdomen 

 covered with white woolly formations. Squeezed between 

 the fingers the insect leaves a blood red spot. The 

 wingless insects are covered with long white woolly 

 tufts made of a waxy exudation, which are prolonged 

 downwards like a frieze of wool. The bark where the 

 insect attaches itself becomes hypertrophied, and large 

 protuberances are formed, which ultimately become 

 cankerous and the woody tissues are destroyed for 

 considerable distances along the stem and branches. 

 The branches badly attacked should be pruned back 

 and burned, and the stem and main branches should 

 be well scraped of all diseased formations, and thoroughly 

 painted over with some powerful insecticide such as 

 the concentrated sulphur-lime mixture, or a strong- 

 emulsion of soap and petroleum to which some crude 

 carbolic acid has been added, or an emulsion of pittelein 

 i per cent., or a mixture made of glue and creosote 



