Көк күміс қайың қоңызы

Species of beetle

The emerald ash borer (Agrilus planipennis), also known by the acronym EAB, is a green buprestid or jewel beetle native to north eastern Asia that feeds on ash species (Fraxinus spp.). Females lay eggs in bark crevices on ash trees, and larvae feed underneath the bark of ash trees to emerge as adults in one to two years. In its native range, it is typically found at low densities and does not cause significant damage to trees native to the area. Outside its native range, it is an invasive species and is highly destructive to ash trees native to Europe and North America. Before it was found in North America, very little was known about emerald ash borer in its native range; this has resulted in much of the research on its biology being focused in North America. Local governments in North America are attempting to control it by monitoring its spread, diversifying tree species, and through the use of insecticides and biological control.

French priest and naturalist Armand David collected a specimen of the species during one of his trips through Imperial China in the 1860s and 1870s. He found the beetle in Beijing and sent it to France, where the first brief description of Agrilus planipennis by the entomologist Léon Fairmaire was published in the Revue d'Entomologie in 1888. Unaware of Fairmaire's description, a separate description naming the species as Agrilus marcopoli was published in 1930 by Jan Obenberger. They leave tracks in the trees they damage below the bark that are sometimes visible. Adult beetles of other species can often be misidentified by the public.

The emerald ash borer life cycle can occur over one or two years depending on the time of year of oviposition, the health of the tree, and temperature. After 400–500 accumulated degree days above , adults begin to emerge from trees in late spring, and peak emergence occurs around 1,000 degree days. After emergence, adults feed for one week on ash leaves in the canopy before mating, but cause little defoliation in the process. Males hover around trees, locate females by visual cues, and drop directly onto the female to mate. Mating can last 50 minutes, and females may mate with multiple males over their lifespan. Emerald ash borer has four larval instars. By feeding, larvae create long serpentine galleries. Fully mature fourth instar larvae are long. and in the Pacific Northwest in Oregon. In eastern Europe, a population was found in Moscow in 2003. From 2003 to 2016, this population has spread west towards the European Union at up to per year and is expected to reach central Europe between 2031 and 2036.

In its native range, emerald ash borer is only a nuisance pest on native trees, as population densities typically do not reach levels lethal to healthy trees. In China, it infests native Fraxinus chinensis, F. mandshurica, and F. rhynchophylla; in Japan it also infests F. japonica and F. lanuginosa. In Europe, F. excelsior is the main ash species colonized, which is moderately resistant to emerald ash borer infestation. Ash susceptibility can vary depending on the attractiveness of chemical volatiles to adults, or the ability of larvae to detoxify phenolic compounds. Another non ash host has also been discovered, Olea europaea, albeit in a lab setting. Adults prefer to lay eggs on open grown or stressed ash but readily lay eggs on healthy trees amongst other tree species. Ashes that grow in pure stands, whether naturally occurring or in landscaping, are more prone to attack than isolated trees or ones located in mixed forest stands. Ashes used in landscaping also tend to be subjected to higher amounts of environmental stresses including compacted soil, lack of moisture, heating effects from urban islands, road salt, and pollution, which may also reduce their resistance to the borer. Furthermore, most ashes used in landscaping were produced from a handful of cultivars, resulting in low genetic diversity. Without factors that would normally suppress emerald ash borer populations in its native range (e. g., resistant trees, predators, and parasitoid wasps), populations can quickly rise to damaging levels. Green ash and black ash trees are preferred by emerald ash borer. White ash is also killed rapidly but usually only after all green and black ash trees are eliminated. Blue ash is known to exhibit a higher degree of resistance to emerald ash borer, which is believed to be caused by the high tannin content in the leaves making the foliage unpalatable to the insect. While most Asian ashes have evolved this defense, it is absent from American species other than blue ash. Researchers have examined populations of so called "lingering ash", trees that survived ash borer attack with little or no damage, as a means of grafting or breeding new, resistant stock. Many of these lingering ashes were found to have unusual phenotypes that may result in increased resistance. Aside from their higher tannin content, Asian ashes also employ natural defenses to repel, trap, and kill emerald ash borer larvae. Although studies of American ashes have suggested that they are capable of mustering similar defensive mechanisms, the trees do not appear to recognize when they are under attack. Many of the specialized predators and parasitoids that suppressed emerald ash borer in Asia were not present in North America. Predators and parasitoids native to North America do not sufficiently suppress emerald ash borer, so populations continue to grow. Birds such as woodpeckers feed on emerald ash borer larva, although the adult beetles have not been used by any American fauna as food. and overwintering emerald ash borer survive down to average temperatures of because of antifreeze chemicals in the body and insulation provided by tree bark.

Emerald ash borer threatens the entire North American genus Fraxinus. It has killed tens of millions of ash trees so far and threatens to kill most of the 8.7 billion ash trees throughout North America. Costs for managing these trees can fall upon homeowners or local municipalities. For municipalities, removing large numbers of dead or infested trees at once is costly, so slowing down the rate at which trees die through removing known infested trees and treating trees with insecticides can allow local governments more time to plan, remove, and replace trees that would eventually die. This strategy saves money as it would cost $10.7 billion in urban areas of 25 states over 10 years, while removing and replacing all ash trees in these same areas at once would cost $25 billion (with another estimate putting the removal alone at $20–60 billion).

In areas where emerald ash borer has not yet been detected, surveys are used to monitor for new infestations. Visual surveys are used to find ash trees displaying emerald ash borer damage, and traps with colors attractive to emerald ash borer, such as purple or green, are hung in trees as part of a monitoring program.

In areas where emerald ash borer is non native and invasive, quarantines, infested tree removal, insecticides, and biological control are used to reduce damage to ash trees.

Once an infestation is detected, quarantines are typically imposed by state, or previously, national government agencies disallowing transport of ash firewood or live plants outside of these areas without permits indicating the material has been inspected or treated (i. e., heat treatment or wood chipping) to ensure no live emerald ash borer are present in the bark and phloem. In urban areas, trees are often removed once an infestation is found to reduce emerald ash borer population densities and the likelihood of further spread. Urban ash are typically replaced with non ash species such as maple, oak, or linden to limit food sources. In rural areas, trees can be harvested for lumber or firewood to reduce ash stand density, but quarantines may apply for this material, especially in areas where the material could be infested. Kentucky Extension specialists suggest selecting uncommon species to replace removed ashes in the landscape. Previous generations created monocultures by planting ash trees in an overabundance, a factor in the extent of the devastation caused by the emerald ash borer. Favoring instead a diversity in species helps keep urban forests healthy. University of Kentucky scientists suggest choosing monotypic species such as the pawpaw, yellowwood, Franklin tree, Kentucky coffeetree, Osage orange, sourwood, and bald cypress.

Insecticides with active ingredients such as azadirachtin, imidacloprid, emamectin benzoate, and dinotefuran are currently used. Dinotefuran and imidacloprid are systemic (i. e., incorporated into the tree) and remain effective for one to three years depending on the product. Insecticides are typically only considered a viable option in urban areas with high value trees near an infestation. Ash trees are primarily treated by direct injection into the tree or soil drench. Some insecticides cannot be applied by homeowners and must be applied by licensed applicators. Damage from emerald ash borer can continue to increase over time even with insecticide applications. Three species imported from China were approved for release by the USDA in 2007 and in Canada in 2013: Spathius agrili, Tetrastichus planipennisi, and Oobius agrili, while Spathius galinae was approved for release in 2015. Excluding Spathius galinae, which has only recently been released, the other three species have been documented parasitizing emerald ash borer larvae one year after release, indicating that they survived the winter, but establishment varied among species and locations.