Tetrastichus planipennisi
Encyclopedia
Tetrastichus planipennisi is a parasitic non stinging wasp of family Eulophidae
which is native to North Asia
. It is a parasitoid of the emerald ash borer
(Agrilus planipennis Fairmaire, family Buprestidae), an invasive species
which has destroyed tens of millions of ash trees in its introduced range in North America
. As part of the campaign against the emerald ash borer (EAB), American scientists in conjunction with the Chinese Academy of Forestry searched since 2003 for its natural enemies in the wild leading to the discovery of several parasitoid wasps, including Tetrastichus planipennisi which is a gregarious endoparasitoid of EAB larvae on Manchurian Ash (Fraxinus mandschurica
) and has been recorded to attack and kill up to 50 percent of EAB larvae.
of the EAB along with two other wasps, Oobius agrili
, a solitary, parthenogenic egg parasitoid, and Spathius agrili
, a gregarious larval ectoparasitoid. However of the three, Tetrastichus planipennisi has showed best results in affecting EAB and establishing surviving populations.
Research on the viability of as an effective biocontrol agent is ongoing in the US. Laboratory methods have been developed for continuous rearing of this and other species of EAB parasitoid wasps. Extensive studies on the specificity of these parasitoids on native beetles and other insects has revealed that in laboratory no-choice assays, Tetrastichus attacked only actively feeding EAB larvae in ash branches and rejected all non-EAB species as hosts.
along with the release of non-stinging wasps that are the beetle's natural enemies. Researchers with USDA's Agricultural Research Service
are testing the viability of Beauveria bassiana
, a fungus
with known insecticidal properties, as a biocontrol agent. The release of the wasp and fungus has been done in the states of Michigan
, Illinois
, Indiana
, Ohio
, West Virginia
and Maryland
and are planned for other states. The fungus has been recorded as killing beetles without harming the wasps.
Eulophidae
Eulophidae is a large family of hymenopteran insects, with over 4,300 described species in some 300 genera . The family as presently defined also includes the genus Elasmus, which was previously treated as a separate family, "Elasmidae", and is now treated as a subfamily of Eulophidae...
which is native to North Asia
North Asia
North Asia or Northern Asia is a subregion of Asia, consisting of the Asian portion of Russia.The Phillips Illustrated Atlas of the World 1988 defines it as being most of the former USSR, the part that is to the east of the Ural Mountains...
. It is a parasitoid of the emerald ash borer
Emerald ash borer
The emerald ash borer is a green beetle native to Asia.In North America the borer is an invasive species, highly destructive to ash trees in its introduced range. The potential damage of this insect rivals that of Chestnut blight and Dutch Elm Disease...
(Agrilus planipennis Fairmaire, family Buprestidae), an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
which has destroyed tens of millions of ash trees in its introduced range in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. As part of the campaign against the emerald ash borer (EAB), American scientists in conjunction with the Chinese Academy of Forestry searched since 2003 for its natural enemies in the wild leading to the discovery of several parasitoid wasps, including Tetrastichus planipennisi which is a gregarious endoparasitoid of EAB larvae on Manchurian Ash (Fraxinus mandschurica
Fraxinus mandschurica
Fraxinus mandschurica is a species of Fraxinus native to northeastern Asia in northern China, Korea, Japan and southeastern Russia.Also Known as 'Chinese Oak'....
) and has been recorded to attack and kill up to 50 percent of EAB larvae.
Life cycle
Tetrastichus planipennisi parasitize EAB larvae by drilling through the bark and laying eggs on its host. The hatching parasitoid larvae feed and develop on the EAB larva, resulting in its death. Tetrastichus completes at least four generations each year and one EAB larva can produce up to 127 Tetrastichus adults. Tetrastichus planipennisi survive the winter as larvae inside their host or host gallery under the bark of ash trees.Biological control
Tetrastichus planipennisi, a gregarious larval endoparasitoid, has been introduced and released into the United States of America as a possible biological controlBiological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
of the EAB along with two other wasps, Oobius agrili
Oobius agrili
Oobius agrili is a parasitic non-stinging wasp of family Encyrtidae which is native to North Asia. It is a parasitoid of the emerald ash borer , an invasive species which has destroyed tens of millions of ash trees in its introduced range in North America...
, a solitary, parthenogenic egg parasitoid, and Spathius agrili
Spathius agrili
Spathius agrili is a parasitic non-stinging wasp of family Braconidae which is native to North Asia. It is a parasitoid of the emerald ash borer , an invasive species which has destroyed tens of millions of ash trees in its introduced range in North America...
, a gregarious larval ectoparasitoid. However of the three, Tetrastichus planipennisi has showed best results in affecting EAB and establishing surviving populations.
Research on the viability of as an effective biocontrol agent is ongoing in the US. Laboratory methods have been developed for continuous rearing of this and other species of EAB parasitoid wasps. Extensive studies on the specificity of these parasitoids on native beetles and other insects has revealed that in laboratory no-choice assays, Tetrastichus attacked only actively feeding EAB larvae in ash branches and rejected all non-EAB species as hosts.
Combined use with fungal pathogen
The latest initiative at biocontrol involves the use of a fungal pathogenPathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
along with the release of non-stinging wasps that are the beetle's natural enemies. Researchers with USDA's Agricultural Research Service
Agricultural Research Service
The Agricultural Research Service is the principal in-house research agency of the United States Department of Agriculture . ARS is one of four agencies in USDA's Research, Education and Economics mission area...
are testing the viability of Beauveria bassiana
Beauveria bassiana
Beauveria bassiana is a fungus that grows naturally in soils throughout the world and acts as a parasite on various arthropod species, causing white muscardine disease; it thus belongs to the entomopathogenic fungi. It is being used as a biological insecticide to control a number of pests such as...
, a fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
with known insecticidal properties, as a biocontrol agent. The release of the wasp and fungus has been done in the states of Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...
, Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
, West Virginia
West Virginia
West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...
and Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
and are planned for other states. The fungus has been recorded as killing beetles without harming the wasps.