Cankerworm

“ It lives exposed on the outside of twigs and leaves where the birds can easily secure it, and is without distasteful hairs or spines on its integument. The English Sparrow, which is said to have been imported into America to check the ravages of this insect, is no doubt our most efficient cankerworm eater in the cities. We have watched these much-despised birds picking larvæ from the elms at all hours of the day from early morning to twilight, and even during rains. The Robin is also an efficient destroyer of cankerworms, especially of the moths which are found at the base of the tree. ”

“ Chickadees like to eat the eggs of cankerworms; and for a single meal one of these tiny birds will eat two hundred and fifty eggs, and he will take several meals a day. Now, cankerworms destroy our apples. When they get into an orchard in force, it looks, as Miss Merriam says, as if it had been burned over. Robins, cat-birds, and shrikes, and several others, like to eat cutworms, which destroy grass and other plants. ”

“ This gives a total of nearly twenty thousand cankerworm moth eggs destroyed by four birds in a few minutes. The Chickadee is very fond of the eggs of this moth and hunts them assiduously during the four weeks of the summer when the moths are laying them.
The Nighthawk, which feeds mainly in the evening, and which is equally at home in the pine barrens of Florida, the prairies of Dakota, or the upper air of New York City, is a slaughterer of insects of many kinds. ”

“ Insect eggs of many other kinds were found in the food, among them those of the tent caterpillar and the fall cankerworm, and the larvae of several kinds of moths, including those of the common apple worm. ”

“ The hundred bird stomachs reported upon represent 39 species of birds, all but three of which had eaten cankerworms. Eighteen of the species had at least one individual which had eaten 100% cankerworms. Including birds previously mentioned in the literature as enemies of cankerworms the list now totals 75 species. ”

“ Within the groups, individuals with smaller wings were favored; they survived and reproduced in greater numbers than other individuals. Over many generations then, the wings in some groups became very small or were entirely lost. Sometimes this loss of wings occurred in all the adult forms, as in the fleas. Individuals of only one sex may be wingless, as are the females of two Illinois moths, one of which produces bagworms and the other cankerworms. In two groups, the termites and the ants, a wingless worker or soldier caste is produced ”

“ Persian, 260 Cankerworms (See “Inchworms”) ‘Caperata’ (‘Little Fantasy’) , 129 ‘Caprice,’ 286 Caraway thyme, 274 Carex elegantissima (Morrowi variegata) , 110 Carissa grandiflora nana compacta (Natal Plum) , 110 Carnations, 266 Carpet bugle, 260 ‘Carpet of Snow,’ 282 Caryopteris, 229 Caryopteris incana (Blue Spirea) , 240 Caryota urens (fishtail palm) , 63 Cassiope lycopodioides, 240 Catchfly, 273–74 Cedar, 234 ”

“ They have to take good care of themselves while their wings are growing, for fear something will eat them up.
“In the silkworm, they wait till they have spun, and then they bake the cocoons to kill the animal inside, or else he would eat out. Then they unwind the silk. Each one lays about six or seven hundred eggs, so they can afford to kill a few.
“Some of the insects of this class are not so pleasant to have. The canker-worm belongs to it, and so does the moth that gets into houses and eats up woollen things. ”

“ Important advantages may also be derived from the presence of foliage plants, even though they are incapable of producing ozone, for, if properly taken care of, they will contribute essentially to the maintenance of a hygienic degree of humidity in the atmosphere of the apartment.
The Canker-Worm—According to Professor Riley's pamphlet on the subject, there are two worms called the canker-worm, both destructive to apple, elm, and maple trees, and much alike. One is called the spring canker-worm, because the moths come out of the ground in the spring ”

“ Enormous numbers of insects are consumed by a flock. The elm-beetle, which destroys the beauty, if not the life, of some of our finest shade trees, would be exterminated if there were cedarbirds enough. One flock within a week rid a New England village of this pest that had eaten the leaves on the double row of elms which had been the glory of its broad main street for over a hundred years. When you see these birds in an orchard, look for better apples there next year. Canker-worms are a bon bouche to them; so are grubs and caterpillars, especially cutworms. ”

“ In addition to the insects affecting orchard fruits, there are hosts of enemies to the foliage. Nearly all of the latter, fortunately, are also open to destruction by means of the spraying machine. The canker worm is one of the most destructive of these foliage pests; at occasional intervals during the last century it has denuded thousands of orchard and shade trees in many parts of Canada and the United States. Its different stages are shown in Fig. 4. The damage is done by the worms or larvæ which hatch from masses of small cylindrical eggs (e) , usually deposited upon the bark of the trees. ”

“ We spray before the blossom opens, for bud moth, canker-worm and tent-caterpillar, and after the petals have fallen for codling-moth, tussock-moth, and fall web-worm. We have been successful except as to bud moth and fall web-worm. We believe we have greatly reduced the codling-moth by spraying, and we know we have destroyed the canker-worm. Have never successfully combated borers, excepting with knife and wire. Fall web-worms are burned in the tree with a gasoline torch, or the small limbs with webs are removed and burned. ”

“ A canker always originates in a wound affecting the cambium, and usually in a small wound such as an insect puncture or frost nip; if undisturbed the dead parts would heal over by cork and callus, but if recurring frost-cracks break open the coverings, or if insects or fungi penetrate the callus and invade the cambium, irregularities of growth due to the occluding tissue on the one hand, and continued growth of the still unimpaired cambium on the opposite side of the injured shoot on the other, result in the canker. Frost cankers occur on fruit-trees, Vines, Beeches, etc. ”

“ It will be remembered that these trees have greatly suffered, in past times, from the ravages of canker-worms. Moreover, the impenetrable state of the surface soil, the exhausted condition of the subsoil, and the deprivation of all benefit from the decomposition of accumulated leaves, which, in a state of nature, the trees would have enjoyed, but which a regard for neatness has industriously removed, have doubtless had no small influence in diminishing the vigor of the trees, and thus made them fall unresistingly a prey to insect devourers. ”

“ This situation they resorted to afterwards for several successive summers, each season building two nests, never using the same nest a second time, although each time it was left as clean and in as good condition as when first made. Indeed, this species is remarkable for its cleanliness, both in its own person and in its care of nestlings and nests.
They feed their young chiefly with insects, especially small caterpillars; the destructive canker-worm is one of their favorite articles of food, also the larvæ of insects and the smaller moths. ”

“ As the worms are leaf-eaters, spraying with London purple or Paris green, as for canker-worms, must kill many. Whenever their nests are seen they should, if possible, be gathered and burned, and in a badly infested orchard it will pay to rake and burn all the leaves under the trees. ”

“ As illustrated so well by the history of the incursions of the army worm and canker worm, it is only by a combination between farmers and orchardists that these and other pests can be kept under. The matter can be best reached by legislation. We have fish and game laws; why should we not have an insect law? Why should we not frame a law providing that farmers, and all owning a garden or orchard, should cooperate in taking preventive measures against injurious insects, such as early or late planting of cereals, to avert the attacks of the wheat midge and Hessian fly ”

“ When four weeks old they creep to the ground, or let themselves down by spinning a silken thread, and burrow from two to six inches in the soil, where [Pg 202] they change to chrysalids in a day or two, and in this state live till late in the fall, or until the early spring, when they assume the imago or moth form. The sexes then unite, and the eggs are deposited for the next generation.
The Canker worm is widely distributed, though its ravages used to be confined mostly to the immediate vicinity of Boston. We have seen specimens of the moth from Illinois. Riley has found it in Missouri. ”

“ Among that beautiful family of moths, the Phalænidæ, comprising the Geometers, Loopers, or Span-worms, are two formidable foes to fruit growers. The habits of the Canker worm should be well known. With proper care and well-directed energy, we believe their attacks can be in a great measure prevented. The English sparrow, doves and other insectivorous birds, if there are any others that eat them, should be domesticated in order to reduce the number of these pests. ”

“ The whole almond family are liable to the attacks of insects. Canker-worms of one or of several species often strip them of their leaves; the tent-caterpillars pitch their tents among the branches and carry on their dangerous depredations; the slug-worms, the offspring of a fly called Selandria cerasi, reduce the leaves to skeletons, and thus destroy them; the cherry-weevils penetrate their bark, cover their branches with warts and cause them to decay ”

“ Canker is sometimes cured by cutting out the cankered part, and admitting air to the roots; and the insect called the American blight may be removed by washing the tree with a brush and soft soap and warm water, or by plastering it over with a mixture of stiff clay and water. ”

“ Growth is comparatively slow, and there is much dying back or dying out of the slender branchlets.
The evidence indicates that this is not a virus trouble, but a systemic defect, probably caused by chromosome aberration or gene abnormality. It is significant that this trouble occurs only in hybrids. Such trees never flower. We have known four such cases, two of which are now dead. Similar types appear in other species as inherited deviations from normal.
Insect Injuries
A heavy attack from the spring canker worms developed in 1951, but spraying with DDT on May 24th prevented serious damage. ”

“ S. A. Forbes (1883) reports that 5 stomachs from a canker-infested orchard contained 94 percent insects; of which 66 percent were canker-worms, Coleoptera 23 percent, spiders 6 percent, Hymenoptera 2 percent, and Hemiptera 1 percent. A. H. Howell (1907) found a cotton-boll weevil in one stomach from Texas; E. R. Kalmbach (1914) reports that of seven Utah stomachs, two contained alfalfa weevils, forming 25 percent of the food in one; and Prof. Aughey (1878) found an average of 11 locusts in 7 Nebraska birds. ”

“ By well-concerted action among agriculturists, who should form a Board of Destruction, numbering every man, woman and child on the farm, this fearful scourge may be abated by the simplest means, as the cholera or any epidemic disease can in a great measure be averted by taking proper sanitary precautions. The Canker worms hatch out during the early part of May, from eggs laid in the fall and spring, on the branches of various fruit-trees. ”

“ They were even more fearless [Pg 490] and tame than the americana, and in one instance a pair were taken by the hand, and afterwards kept in confinement. They appeared around Boston in large flocks, and remained through April. One was shot in Newton by Mr. Maynard, June 13. It was found in an apple-tree, and its crop was full of canker-worms. In Eastern Maine it is resident throughout the year, and, like the other species, breeds in winter. In Western Maine Professor Verrill has found it a common winter visitant, but it is not known to be resident. ”

“ Others, and this is the most common mode of parasitism, attack the insect in its larva state; others, in the pupa state, and still others in the perfect, or imago state. Dr. Leidy has shown that the wood-devouring species of beetle, Passalus cornutus, and some Myriopods, or "thousand legs," are, in some cases, tenanted by myriads of microscopic plants and worms which luxuriate in the alimentary canal, while the "caterpillar-fungus" attacks sickly caterpillars, filling out their bodies, and sending out shoots into the air, so that the insect looks as if transformed into a vegetable. ”

“ The insects that trouble us most are: Canker-worm, tent-caterpillar, fringed-wing bud moth, handmaid-moth or yellow-necked caterpillar, roundheaded borer and the tussock-moth caterpillar on our trees; and codling-moth, gouger and tree cricket on and in our fruit. We spray annually, using a horse-power machine, illustrated in former reports of the State Horticultural Society, for the leaf-eating insects named, using London purple and clear water, sometimes adding lime. ”

“ It is easy to see how such an area of Necrosis may become a Canker if the dead tissues split or slough off, and fungi or insects obtain access to the callus at the margins of the area, setting up the disturbances described on p. 222. As matter of fact many Cankers—e.g. those of the Larch disease, and those due to Nectria, or Aphides, etc.—often begin as flattened or depressed areas of Necrosis started by frost, and many small necrotic patches would eventually become Cankers if not healed up by the callus. ”