Bark Beetles

Bark Beetles Bark beetles belong to the insect order Coleoptera and the family Scolytidae. The bark beetle adults are small, rarely exceeding 1/3 inch in length, they are very capable of killing even the largest host trees with a mass assault, girdling them or inoculating them with certain lethal pathogens.

Some species routinely attack the trunks and major limbs of their host trees, other bark beetle species mine the twigs of their hosts, pruning and weakening trees and facilitating the attack of other tree pests, other species favor broadleaf trees and can be equally damaging. Bark Beetles are tiny naturally occurring insects that contribute to the death of thousands of trees in the Southwest each year.

Most species of conifers are utilized by bark beetles. Even freshly cut logs are an ideal host for many bark beetles. The buildup of beetle populations, whether in infested trees or firewood, can then attack nearby live trees. Precautionary steps can reduce the likelihood of bark beetles, that have infested firewood, attacking live trees.

Life Cycle: Bark beetle females lay small, oval, whitish eggs just beneath the outer bark. After the eggs hatch, the tiny larvae mine galleries that branch out from the egg-laying gallery. At first the larval mines are very narrow, but they gradually increase in diameter as the larvae grow. Pupation occurs within or beneath the bark in enlarged chambers at the ends of the larval tunnels. Pupae are usually plump and whitish.

Adults can emerge at any time of year, if they are fully developed and the temperatures are high, but emergence is most common in late spring and again in late summer to early fall. After emergence, adults may re-infest the same tree or, in most cases, disperse to attack susceptible trees elsewhere. Most bark beetle species have two or more generations a year in California, depending on temperature. At warmer locations, the season of attack is usually longer and beetles have more generations per year in comparison with cooler coastal or high-elevation locations.

Egg: off-white, oval, and tiny, eggs are found only in the female’s egg gallery in the live bark of the host tree. Larvae: Larvae are legless, white, multisegmented, ¼ inch long or less at maturity, Cshaped, with yellowish-brown head capsule and chewing jaws. Pupa: Generally found near the end of each larval gallery, each pupa resembles an off white, quiescent, non-feeding “mummy” of the adult it will become. At maturity, pupae are dark brown to black.

Habitat and Hosts: Host preferences by different bark beetle species are fairly specific; some attack only pines while others are restricted to spruce, fir, Douglas fir or other host conifers. Some Scolytus species attack distressed fruit or shade trees. While it damages and can kill Siberian elms and related species, it and its associated hitchhiking pathogen, Dutch elm disease, are a lethal combination for American elm.

Damage: Bark beetles mine the inner bark on twigs, branches, or trunks of trees and shrubs. This activity often starts a flow of tree sap in conifers, but sometimes even in hardwoods like elm and walnut. The sap flow is accompanied by the sawdustlike frass created by the beetles. Frass accumulates in bark crevices or may drop and be visible on the ground or in spider webs. Small emergence holes in the bark are a good indication that bark beetles were present. Removal of the bark with the emergence holes often reveals dead and degraded inner bark and sometimes new adult beetles that have not yet emerged. Bark beetles frequently attack trees weakened by drought, disease, injuries, or other factors that may stress the tree. Bark beetles can contribute to the decline and eventual death of trees, however only a few aggressive species are known to be the sole cause of tree mortality.

Control: Except for general cultural practices that improve tree vigor, little can be done to control most bark beetles once trees have been attacked. Because the beetles live in the protected habitat beneath the bark, it is difficult to control them with insecticides. If trees or shrubs are infested, prune and dispose of bark beetle-infested limbs. If the main trunk is extensively attacked by bark beetles, the entire tree or shrub should be removed. Unless infested trees are cut and infested materials are quickly removed, burned, or chipped on site, large numbers of beetles can emerge and kill nearby host trees, especially if live, unattacked trees nearby are weakened or stressed by other factors. Never pile infested material adjacent to a live tree or shrub.

If you ever have any bug related questions feel free to call us either at Beyond Pest Control. Once again, and I can’t stress this enough we are on call twenty four hours a day seven days a week to kill those bugs, we aren’t kidding whether you call us at 9 am or midnight we will be available to take your call and either get rid of the bug infestation, or answer any questions you may have concerning the bug issue.
I can honestly guarantee that there will be someone to answer that call. We make it our business to make you bug free!

If you have any questions about pest control check out the rest of our website or go to our blog at http://nypestpro.blogspot.com.

Beyond Pest Control.

Our pest control specialists service all NYC boroughs, including Queens, Brooklyn, Bronx, Manhattan, Long Island (both Nassau & Suffolk counties), Staten Island and even both Westchester & Rockland counties.