This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
It is of first importance to know the nature and habits of insects that trouble you, when to expect them, when and where their eggs are laid, and whether they are most readily destroyed in the egg, larva or perfect state, so that the preventives or remedies may be intelligently applied. In all cases one light application of a remedy in the early stages of insect life will be more effectual than many after they have toughened by age; and the astonishing rapidity with which many kinds of insects increase, if allowed to get established, shows the importance of constant vigilance as well as early action.
Different sections of our country are often troubled with insects peculiar to that section only; still some of the different remedies recommended may be found effectual. For those nurserymen who are unfortunate enough to be located where the Rocky Mountain locust (Cal-optenus spretus) occasionally swoops down and devours an entire nursery for breakfast, I would recommend the reports of the United States Entomological Commission's very exhaustive treatise, that can be had for the asking.
Plant lice (Aphides) and root lice (Erisoma) are among the most troublesome lice to the nurseryman and florist. Their wonderful reproductive powers make them very formidable enemies; for one female of the green-fly in five generations will have six thousand millions of descendants - provided there is no small-pox or cholera among them. Those infesting the leaves and branches are easy to conquer compared to those attacking the roots; for the former tobacco smoke is the most effectual for indoor plants. Trees and outdoor plants may be syringed with tobacco water, whale oil soap suds, hot water; and a writer in the Gardener's Monthly recommends a mixture of crude carbolic acid and common soft-soap, two or three tablespoonfuls to a quart of soap, or as much acid as the soap will cut. For the latter we have no thorough practical remedy; like the grape Phylloxera and other root insects they seem quite beyond our reach. If on young stock, the ground may be scraped back so as to expose the roots and then apply hot water at about 200°; it will kill all within reach without injury to the trees.
Any poison put in the water would be wasted, as the soil would filter it before penetrating to many roots.
Bud worms (Penthina oculana, H., and Loxo-taenia rosaceana, H.) The larvae of these small moths destroy the leaf-buds of the apple and pear as they are about to expand, and as soon as the leaflets are large enough they roll them together to protect themselves, making it a difficult matter to reach them. Paris green in water would reach many, but where they are not too numerous hand-picking would be the safest.
The larva of the May beetle (Phyllophaga fusea) or white grub, as it is popularly called, feeds on roots and has quite a fancy for strawberry roots, but is by no means confined to them, eating the roots of most trees where finer roots, such as grass or weeds are not at hand. A few days ago I had occasion to dig up an old stump of a peach tree, diameter about six inches, where I found seventy five of these grubs eating the decaying bark and wood, which shows they can get a living on quite a variety of food.
The beetles lay their eggs in sod, in matted strawberry beds and at the collar of trees. The grubs live three years in the ground before they come out as beetles. One of the best preventives is to plant in such lands only as have had thorough cultivation for at least three years previous. The beetles can be shaken from trees during the day, when they are sluggish, on sheets and destroyed. They eat the foliage of trees. The cherry orchard on the State farm suffered most from them, though some sweet chestnut trees looked quite ragged.
For the imported oyster-shell bark louse (As-pidiotus conchiformis) apply pure raw linseed oil in June.
Pear and cherry leaf slug (Selandria cerasi, P.] and rose slug (S. rosae, H.) are often troublesome in the nursery. The eggs are laid on the under side of the leaf in May and June by sluggish, black saw-flies. The larvae feed exclusively on the upper side of the leaf during the night and on dark cloudy days, hiding on the under side from the bright sun. When full fed and after changing their skin four times (after the the last molt the cherry slug is not slimy) they descend to the ground entering two or three inches below the surface to undergo their transformation. One or two applications of air-slacked lime dusted on the leaves in the evening is a sure cure. Whale oil soap suds, white hellebore and Paris green are also good remedies.
Peach tree borer (Aegeria exitosa, S.) will not trouble nursery stock much if the peach orchards in the vicinity are kept clean of borers. Nursery stock may be protected by thoroughly banking up the soil with the plow during July, August and September to prevent the parent moth from laying her eggs at the collar.
Red spider (Trombidium telarium, H.), an imported mite, very troublesome in the greenhouse, also often found in dry seasons on outdoor trees and plants, especially evergreens. It appears only when there is too much heat and too little moisture. Hence the remedy is apparent, plenty of water on the under-side of the leaf. A little soap or carbolic acid would aid in their destruction.
The mealy bug is a very troublesome pest in the greenhouse. Hot water, kerosene oil in soapsuds is sure death to the bugs, but also to the plants if the application is too strong.