The statements that are here made are intended as advice rather than as directions. They are chosen from good authorities (mostly from Slingerland and Crosby in this case); but the reader must, of course, assume his own risk in applying them. The effectiveness of any recommended treatment depends very largely on the care, thoroughness, and timeliness with which the work is done; and new methods and practices are constantly appearing as the result of new investigations. The dates given in these directions are for New York.
Aphis or plant-louse.—The stock remedies for aphides or plant-lice are kerosene emulsion and the tobacco preparations. Whale-oil soap is also good. The tobacco may be applied as a spray, or in the house as fumigation; the commercial forms of nicotine are excellent. (See page 194.) Be sure to apply the remedy before the leaves have curled and afford protection for the lice; be sure, also, to hit the underside of the leaves, where the lice usually are. The presence of lice on trees is sometimes first discovered from the honey-dew that drops on walks.
Usually the emulsion is diluted with 10-15 parts of water for plant-lice (see formula, page 194); but some of the species (as the dark brown cherry-leaf louse) require a stronger emulsion, about 6 parts of water.
The lady-birds (one of which is shown in Fig. 234) destroy great numbers of plant-lice, and their presence should therefore be encouraged.
Apple-maggot or “railroad-worm.”—The small white maggots make brownish winding burrows in the flesh of the fruit, particularly in summer and early fall varieties. This insect cannot be reached by a spray as the parent fly inserts her eggs under the skin of the apple. When full-grown, the maggot leaves the fruit, passes into the ground, and there transforms inside a tough, leathery case. Tillage has been found to be of no value as a means of control. The only effective treatment is to pick up all windfalls every two or three days, and either to feed them out or to bury them deeply, thus killing the maggots.
Asparagus beetle.—Clean cultural methods are usually sufficient to prevent the asparagus beetle’s seriously injuring well-established beds. Young plants require more or less protection. A good grade of arsenate of lead, 1 lb. to 25 gal. of water, will quickly destroy the grubs on the foliage of either young or old plants. Apply it with an ordinary sprinkling can, or better, use one of the numerous spraying devices now on the market. The necessity for treatment must be determined by the abundance of the pests. They should not be permitted to become abundant in midsummer or the over-wintering beetles may injure the shoots in the spring.
Blister-mite on apple and pear.—The presence of this minute mite is indicated by small irregular brownish blisters on the leaves. Spray in late fall or early spring with the lime-sulfur wash, with kerosene emulsion, diluted with 5 parts of water, or miscible oil, 1 gal. in 10 gal. of water.
Borers.—The only certain remedy for borers is to dig them out, or to punch them out with a wire. Keep the space about the base of the tree clean, and watch closely for any sign of borers. The flat-headed borer of the apple works under the bark on the trunk and larger branches, particularly where much exposed to sun. The dead and sunken appearance of the bark indicates its presence. The round-headed borer works in the wood of apples, quinces, and other trees; it should be hunted for every spring and fall. On hard land, it is well to dig the earth away from the base of the tree and fill the space with coal ashes; this will make the work of examination much easier.
The peach and apricot borer is the larva of a clear-wing moth. The larva burrows just under the bark near or beneath the surface of the ground; its presence is indicated by a gummy mass at the base of the tree. Dig out the borers in June and mound up the trees. At the same time, apply gas-tar or coal-tar to the trunk from the roots to a foot or more above the surface of the ground.