Insects Injurious to the Apple. 45 



groups varying from fifteen to fifty. The eggs are laid mainly at 

 night and are brown in colour, round, convex above, flattened below 

 and ribbed. In ten days the larva^ hatch out and at once burrow 

 under the bark and soon into the wood. The young caterpillar is 

 pink all over, but when mature is dirty, deep ochre-yellow with a 

 broad stripe of rich mahogany-red down the back ; the head is deep 

 blackish-brown, and there are two deep brown spots on the first 

 segment ; the legs are brown, and the forelegs yellow with brown 

 hooks. When full grown the larvae reach from 3 to 3^ inches in 

 length (Fig. 31). They feed on the trees for three years, tunnelling 

 into the wood most of that time. Xow and then they leave the 

 trees and wander about ; some never return. Numbers of cases have 

 been reported of these larvie being found in the earth devouring and 

 burrowing into the roots of plants, such as dahlias (3). Normally, 

 in the spring of the third year the larva comes to the entrance of the 

 tunnel and close to it forms a cocoon lined with silk and coated 

 outside with wood chips. Pupation takes place as a rule in May. 

 The pupa is rich brown with rings of sharp spines on the abdominal 

 segments. The moth emerges in three or four weeks after pupation. 

 Previous to the emergence the pupa forces its way out of the cocoon 

 and partly out of the opening in the tree ; the empty pupa skins 

 may frequently be seen in that position. When kept under 

 unnatural conditions the caterpillars have taken four years to 

 mature. 



Pkevention and Eemedies. 



Trees in close proximity to others that are attacked may be 

 protected by thickly smearing the trunks over in May with a 

 mixture of clay, lime and soft soap. This should be made into a thick 

 paint and smeared all over the trunk up to eight feet and a thick 

 layer put around the base and the ground. Clay and cow-dung has 

 been found to answer the purpose, but is not nearly as good as the 

 former mixture. This will prevent the eggs being deposited on the 

 trunk and roots where exposed. It is quite useless to scrub the bark, 

 as suggested by Miss Ormerod, for the eggs are laid deep in crevices 

 and would not be reached in the majority of cases, neither can many 

 be rubbed off, as suggested. For killing the larvre in the trees, the 

 best plan is to place lumps of stick cyanide in each hole and smear 

 the whole trunk over with clay, the entrances to the holes being 

 firmly plugged up with the same. 



Paraffin emulsion squirted into the holes is said to be a good 

 remedy, but where the tunnels are very long and tortuous it is very 

 doubtful if many are killed by it. Sulphur and tobacco fumes blown 



