|
Home Feature Articles Bug Book Plant Gallery Library Gardener's Seed Charts & Formulas About Us |
|
|
|
|
Cankerworms are the larvae of small moths of the Geometridae family, and are sometimes referred to as inch worms, measuring worms, spanworms or loopers. Their distinct method of movement identifies them quickly. They loop their body as they crawl, then stretch forward with their thoracic legs or they raise their front legs and straighten out their body in rapid succession. These leaf feeding caterpillars can be destructive defoliators of various fruit trees, shade trees and shrubs. The larvae will feed on the foliage, sometimes leaving only the midribs and large veins. There are nearly, 1200 species found in the United States and Canada, they are generally present for 2 - 3 years in large numbers and then seem to disappear, only to return in about 5 - 8 years. The Fall and the Spring Cankerworms are two of the more common and injurious species that feed on ornamental trees. The common names of these are only indicative of their season of egg laying and their only distinguishing characteristic is the number of prolegs they have. (false legs at the end of the body). Both are indigenous to North America and are found from Nova Scotia and southern Canada to the Carolinas, Texas, Colorado and California. Eggs of both species are laid in large masses of about 100 on the twigs, limbs and trunks of trees. They hatch in the spring as soon as new growth starts and begin to feed on buds and new growth. There are both green and dark larvae of each species. 4-5 weeks after hatching the larvae drop to the ground on silk strands, enter the soil and pupate, usually in the early part of June. Tanglefoot or sticky tree bands can be used for control because the females are wingless they must crawl from the ground up into the trees to lay their eggs, however this is not foolproof and spraying may be needed. Spray with a contact insecticide soon after the larvae become active and new foliage growth is fully expanded. Dormant oil can also be used in the dormant season to kill eggs masses. Bacillus thuringiensis, a spore-forming bacterium which produces a fatal disease in cankerworms has shown excellent results as an effective control.
Caterpillars are the worm-like larvae of butterflies and moths. Some are known by their adult forms such as Gypsy Moth and some by specialized names they are given such as cankerworms, casebearers, cutworms, leafminers, leaf tiers and webworms, to name a few, but all of these are different forms of caterpillars. The Tent Caterpillar is probably one of the most widely known garden pests in the caterpillar group. Technically, caterpillars have cylindrical shaped soft bodies, some of which are hairless, others are hairy and have spine-like protrusions. Some are one color and blend into the natural surroundings, while others are adorned with bright or multi-colors. Their bodies are composed of 13 segments behind the head. The first three segments each have a pair of jointed legs terminating in a single claw, this feature distinguishes caterpillars from true worms, which they somewhat resemble. The abdominal segments typically have soft fleshy projections called prolegs, (usually five pair) which are unjointed sucker feet. These sucker feet have small, tiny hooks at the ends, called crochets, that help the caterpillar hold on to leaves and branches. Caterpillars also have a spinneret near the mouth (jaws), used for making silk. Caterpillars are generally sprayed with a contact insecticide (stomach poison) for their control.
Casebears are moths, whose larvae live in tube-like portable cases and feed or mine in leaves, fruits, flowers or seeds.
Centipedes, sometimes referred to as "thousand leggers" are very swift movers when disturbed and tend to give most people the willies when they see them, but before you attempt to step on the next one you see, understand that, they are more of a beneficial garden insect than an insect pest. Centipedes can be found in wet, damp places, under rocks, logs or even in the compost pile. They generally feed on soil dwelling mites, insect larvae and snails. Millipedes on the other hand are very slow moving and will curl up when disturbed. They are useful as scavengers feeding on decaying plant matter and help to break down organic matter in the compost pile, but millipedes can also become a real garden pest, feeding on plant roots, germinating seeds and tiny seedlings. They can get into vegetables and fruits and can also be found in decaying bulbs. To control millipedes keep areas clean of decaying matter or rotting vegetation. Diazinon* can be used to treat the soil. Wood ashes, diatomaceous earth or cinders can be sprinkled near small plants.
When most of us think of crickets we think of the chirping songs that they sing on hot summer evenings, and most of us wouldn't consider them garden pests. Crickets are relatives of grasshoppers. Most will feed on plants and some are predaceous (feeding on other insects) or both. Tree crickets are the most damaging, especially to growers. The injury caused by tree crickets is not from their feeding, but from their egg laying habits. Those most detrimental to trees and shrubs are the Snowy tree cricket, the Blackhorned tree cricket and the Narrow-winged cricket. They lay their eggs in 2-4 year old shoots on a wide range of ornamental plants. The wound created from this egg laying will have one of three results, a heavily callused and unsightly scar may form over the wound, a branch or stem may die off as a result of the injury or the wounds made by the egg laying may become infected with one of several canker forming fungi, which may often spread to other parts of the plant.
Curculios are beetles with a prominent snout, the head being prolonged forward with biting mouth parts at the end and antennae midway. In appearance they look much like a weevils, but the snout is longer and curved downward more than on a weevil. The adults as well as the larvae feed on plants. Curculios have a habit of playing dead when disturbed by drawing their legs and snout close to their bodies and falling to the ground. Some trees commonly affected by curculios are apple, butternut, cherry, hawthorn, quince, pear, shadbush and walnut to name a few. They will also affect cabbage, cauliflower, horseradish, radish, turnip and other fruit and vegetables.
Cutworms are the larvae or caterpillars of night flying moths in the family Noctuidae. Various species can be found all over the world causing injury to a variety of plants. Depending on the specie of cutworm, their diet will vary, some such as the Black, Bronzed or Dingy will feed on tender young flowers and vegetables with soft stems, cutting off the succulent stems at ground level, others are subterranean like the Glassy or Pale Western cutworms which always remain in the soil feeding on roots and underground stems, while the Red-backed cutworm feeds both above and below the ground on a plant. Some cutworms such as the widely known Variegated cutworm will even climb up into trees to eat buds, foliage or fruit. While many are solitary, one in particular, the Army cutworm will work in large groups or armies, attacking all kinds of vegetation. Those most likely to be troublesome to the gardener are the surface cutworms or those that cut off tender young growth at ground level. These overwinter as partially grown larvae in cells in the soil, under trash, plant debris or clumps of grass. In the Spring they begin to feed, working only at night, while in the daytime they remain coiled up in a ball just under the surface of the ground or in plant debris. When mature or fully grown, they burrow down several inches into the soil to make a cell for pupation which can vary from 1-8 weeks or they overwinter depending on the region of the country. In the south there may be several generations per year, while in the north there will be only one, with the adult (moth) appearing in mid-summer. Adults are brown or gray moths with about a 1 1/2" wingspread. An old method for control that uses no chemicals, is to place collars made of stiff paper, card board or the like around each plant that is set out and pushing this ring down into the ground at least a couple of inches. This will deter any cutworms working just under the surface. You can also use one of the many baits that are on the market or mix your own using wheat bran mixed with molasses and BTK ( Bacillus thuringiensis var. kurstaki). After mixing, apply this in the late afternoon or evening since they are night feeders, at ½ pound per 1000 square feet. |
|
This garden resource is for you. We welcome your comments and suggestions.
Email us on our Feedback Form
.
|
Curculios -