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This material may be available in alternative formats. Timothy J. Gibb and Clifford S. Sadof, Extension Entomologists. By Maintaining Healthy Trees: Vigorously growing trees are less inclined to be damaged by borers than are trees in poor condition. Bronze birch borers are a type of grub that can kill roots, branches, and entire trees. Damage. Timing of pesticide application is important. Main photo taken by John A. Davidson University of Maryland College, Bugwood.org Trees improve air quality, provide cooling and habitat and are a significant part of our culture. Dieback of the canopy is a symptom of Bronze Birch Borer larval infestation; more than one half of the branches may die back as infestation progresses. In later stages of infestation, the trunk will show D-shaped, rust-stained exit holes and may also have swollen extrusions under the bark where the tree tried to grow over larval galleries. Bronze Birch Borer larvae live under the bark and feed on the nutrient and water-conducting vascular tissues. Plants Affected. Soil applications of imidacloprid (Bayer Tree and Shrub Protect I, Xytect, and others) imidacloprid plus clothianidin (Bayer Tree and Shrub Protect II) can be made from between April 1 and May 15. The larvae, which does the damage, are unseen, feeding on the vascular tissue under the bark. Bronze birch borer adult . Sanitation: Remove dying trees and branches before adults emerge in early May. Adults are small beetles with a bronze body. Consequently, bronze birch borer can be a pest of nursery stock (Wohlers 1990, D. A. Herms, unpublished data). This large beetle lays its eggs underneath the bark of the tree, and the larvae burrow through the growing areas (cambium layer) and by preventing the movement and food and water through the tree they soon kill it. Bronze Birch Borer treatment in the spring will prevent the adult beetles from feeding and laying eggs in the tree, whereas summer treatment will kill the larval stage of Bronze Birch Borer feeding under the bark. Two-lined chestnut borers are bluish-black with two parallel yellow stripes running down their wing covers. Chlorotic leaves, sparse foliage and dying upper branches of white, paper and yellow birch trees are often the first visible symptoms of bronze birch borer damage. They pupate in the tree. Bronze birch borer This native beetle attacks stressed birch trees. Exotic pests pose a significant threat to urban trees (e.g. If soil is dry, water trees prior to treatment. Larvae create meandering galleries through the phloem, vascular cambium and etch the xylem, effectively girdling the tree. In general, applications are not made more than once a year. It is a sun-loving insect and may be found crawling on the sunny side of the trunk during late May and early June. Emerging beetles leave … The bronze birch borer is a serious native insect pest. In the spring the larvae mature and pupate in the tree trunk. Independent studies strongly recommend that treatments be applied early, before extensive disruption occurs to the vascular tissues. The bark will split over dead vascular tissues, and trees may die within only two years of the onset of symptoms. Trees need to be closely monitored for symptoms of Bronze Birch Borer as infestation builds in your area.
Bronze birch borers are iridescent and bronze colored. Insecticide Sprays: Between mid-May and mid-June, homeowners can spray infested trees with permethrin (Eight) or Spectracide Bug Stop to kill adults emerging from bark and feeding on leaves. The female deposits her eggs under cracks and crevices of the bark. Bronze birch borer larvae are flat, elongate, legless, nd havea a brown head and white body with forceps at the end of the body. Systemic Insecticide Sprays: A soil drench of systemic insecticides can be used to kill adults that feed on leaves and larvae beneath the bark. The tree responds to canopy dieback by sprouting new (epicormic) branches below the disrupted tissues. The larvae are white with a light brown head. Trouble with this page? The larvae pupate in the xylem in late April or early May. Dieback of the canopy is a symptom of Bronze Birch Borer larval infestation; more than one half of the branches may die back as infestation progresses. Healthy, vigorous birches are most resistant to bronze birch borer attack. Bronze birch borer feeding will cause bark to appear bumpy. Make summer treatment applications in the morning when temperatures are moderate. Birch Leafminer Larvae The Leafminer is a wasp-like insect; they lay eggs in birch leaves and the larvae hatch and feast on the leaves. Closer examination will reveal ridges and bumps on the limbs and branches as well as occasional D-shaped holes in the bark. Bronze Birch Borer larvae live under the bark and feed on the nutrient and water-conducting vascular tissues. The adult bronze birch borer is a slender, olive-bronze, 10 mm long beetle. Injection in the fall (after leaves color but before they fall) can protect the tree for the following season. Birch trees are relatively short-lived and thus old age, adverse weather conditions or other insect-related stresses can all contribute to weakened trees. Purdue University | An equal access/equal opportunity university | Integrity Statement | Copyright Complaints | Maintained by ENTM IT. The adult is a black beetle about 1/2 inch long and has bronzy iridescence on the back. This can reduce the number of borers available to attack your trees. (45) Photo: Cliff Sadof Bronze birch borer adult. Pale white. Bronze Birch Borer taken by Steven Katovich, USDA Forest Service, Bugwood.org. Another way is to maintain healthy trees by watering. Emerald Ash Borer). Trees that receive no corrective measures usually die within a few years after the first dead branches are found. The larvae, which do the damage, are unseen, feeding on the bark’s vascular tissue. Of seven morphological variables measured, the width of the peristoma, an exposed sclerotized portion of the head capsule, provides the clearest separation of instars. They may occasionally tunnel into the xylem (wood) to molt and overwinter. 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