Remedy.—Observe the bark of young trees very closely during the summer, to discover the castings that are ejected; notice the discolored or depressed portions of bark, and cut into them to find and destroy the worm—if it has penetrated the solid wood, pursue it with a piece of stout but flexible wire.
Preventives.—Alkaline washes have been highly recommended, as a means of driving away the mother beetle; soft soap may be used, and a portion of soft or hard soap, placed in the forks of the branches, will dissolve with the rains, and wash down on the bark. These applications, to be efficacious, should be made in May or June. In August, the bark should be examined, and when the worms are cut out, the soap suds may be injected with advantage, especially if the larvæ have not been reached. Birds should be encouraged, particularly the Picæ tribe, which destroy many grubs of the wood-boring insects.
Chrysobothris femorata, or the Thick-legged Buprestris, is another kind of apple-tree borer, very common in some parts of the West. The perfect insect may be seen running up and down the stems of our trees, in June and July. It is a blackish beetle, about half an inch long. The hole, bored by the grub, is flat, and not cylindrical like that of the Saperda. This beetle attacks the stem higher up than the Saperda, but burrows under the bark, and then sinks into the wood much in the same way.
Remedies and Preventives are similar to those above mentioned. Seek for the young worms in their shallow burrows in August, before they have gone deeply into the tree.
Dicerca divaricata, (Say.), or the Cherry-tree Borer, is similar in its habit of boring in the sap wood under the bark, and may be combated in the same way. The perfect insect appears in June and July.
Prenocerus supernotatus, or the American Currant Borer, feeds upon the pith of the stalk. The larva is a small, white grub, which changes into a slender, long-horned beetle; black, edged with chestnut-brown. The wing covers are marked with two small grey dots, anteriorly, and a crescent-shaped one behind the middle.
It is very injurious to the currant bushes in many parts of the country, and constitutes a serious obstacle to growing the plants to a single stem, tree fashion. In the bush form of this plant, the constant reproduction of new shoots compensates for the destruction caused by the borer.
There is another currant borer, an European, which is confined to young shoots; as it is not the larva of a beetle, but of a butterfly, it will be treated in its proper place.
Bostrichus bicaudatus, or the Apple-twig Borer, affects the small twigs, and when numerous, will produce an effect like that called twig-blight, by causing the death of the part and the withering of the leaves, at mid-summer. A small hole will be found near the axil of a leaf; this turns with the twig, and often extends several inches along the pith. The insect is a small, chestnut-brown beetle, 0.25 to 0.35 of an inch long, and is characterized by two projections or horns at the hinder end. Has been found rather common from Michigan to Kansas.
Remedy.—Kill, when found.