Biological Control Program The Biological Control Program is a team of scientists located at various CPHST locations that develops technologies that allow living biological organisms to be used to control invasive plant pests.
Emerald Ash Borer Biological Control. The emerald ash borer (EAB) is a non-native wood-boring beetle that is devastating ash trees in the United States. Since its discovery in Michigan in 2002, APHIS, in conjunction with state, local, and other federal agencies, has led an aggressive campaign to slow the spread of the pest with quarantines, surveys, tree removal, and public outreach programs. In spite of these efforts, the range of EAB has expanded to 25 States due to natural spread and human-assisted movement of EAB-infested materials. To control the pest, the CPHST Otis Lab has been working together with the Forest Service (FS) and Agricultural Research Service (ARS) to implement an EAB biological control program. Four parasitoids, highly specific to EAB, have been identified, evaluated, and approved for release in EAB-infested areas. Three of these biological control agents target the EAB larvae (Spathius agrili, Spathius galiane, Tetrastichus planipennisi), and one, Oobius agrili, targets the EAB egg. A production facility in Michigan supports widespread field releases of these EAB biocontrol agents; currently 22 of the 25 States have released parasitoids. Forging ahead, ARS is evaluating a second EAB egg parasitoid to determine its host specificity and potential to help curtail the pest. (Contact Ken Bloem )
Sirex Woodwasp Biological Control. The sirex woodwasp was discovered in New York in 2005. Since the first discovery, the wasp has been detected in New York, Ohio, Pennsylvania, Vermont and in Ontario, Canada. Sirex has the potential to cause great harm to native pine forests as well as severe economic losses for the lumber industry. In 2006-2009, scientists from the CPHST Otis Lab have been conducting controlled release experiments of the nematode biocontrol agent, Beddingia siricidicola. CPHST, working together with Forest Service, continues to develop survey tools and evaluate the effectiveness of the biological control agent and its relationship with native species for possible open field releases in 2010. (Contact Ken Bloem or Mike Stefan)
Asian Citrus Psyllid Biological Control. The Asian citrus psyllid (ACP), Diaphorina citri, is the primary vector of the bacterium that causes Huanglongbing or greening disease, which is one of the most important diseases of citrus world-wide. Tamarixia radiata is recognized as the most important natural enemy of ACP in several geographic areas around the world. Collections of a strain of T. radiate from Punjab, Pakistan, were recently received into the PPQ Arthropod Quarantine Laboratory in Mission, Texas. Pending completion of host specificity testing required for permitting for environmental release, the Punjab strain will be used as a biological control tool to support area-wide ACP management in Texas and other states where ACP is established. Host specificity testing against native psyllids in California is necessary before release permits for that state will be granted. The CPHST Mission Lab submitted samples of ACP adults and host-plant material to the Texas Citrus Center in Weslaco to test for Huanglongbing disease. Testing and negative results were required in order to ship ACP to the quarantine facility in Riverside, California, to support host range testing there.
Green Treatments for Rangeland Grasshoppers and Mormon Crickets. The CPHST Phoenix Lab continues to partner with the ARS Northern Plains Agricultural Research Laboratory, Utah State University and the APHIS-PPQ Western Region to discover and develop candidate fungal pathogens for use against rangeland grasshoppers and Mormon crickets. The Western Region provides soil samples taken during routine field surveys. Utah State University processes the samples and screens them for new isolates of Beauveria bassiana, Metarhizium anisopliae and Metarhizium acridum. Both Utah State University and ARS scientists evaluate the strains in the laboratory for potential activity. The group then selects the most promising isolates for CPHST scientists working together with ARS and USU in the field to evaluate their efficacy under more natural conditions.
Cactus Mealybug Biological Control. The cactus mealybug (Hypogeococcus pungens) is a pest that is devastating endangered cactus species in Puerto Rico and could threaten similar species in the Western U.S. PPQ has been working with the University of Puerto Rico to develop a quarantine facility to test biological control agents. They are currently testing a new species of parasitic wasp that was found attacking the mealybug in Barbados. The mealybug has been known to occur throughout Florida since 1984, but it has a very limited host range and appears not to be a significant pest. University of Florida Tropical Research Education Center and CPHST scientists discovered multiple biological control agents attacking the cactus mealybug in Florida. Several predatory beetles and a primary parasitoid, Gyranusoidea pseudococci, were found widely distributed across Florida and are likely proving good biological control of the pest. The Florida and Barbados natural enemies may work as classical biological control agents against the cactus mealybug in Puerto Rico.
Insect Biological Control of Perennial Weeds. Exotic perennial weeds are significant pests in a variety of agricultural and natural communities throughout the US. Among these weeds are Russian knapweed (Acroptilon repens), an invader of western US rangelands, and yellow toadflax (Linaria vulgaris), which occurs in crops, grasslands, and riparian areas thorough the northern US. Both weeds have been selected by PPQ as high-priority targets for implementation of biological control. CPHST Fort Collins has worked with international, Federal, state, and university partners to develop and deliver biocontrol agents for both weeds. In 2009, the Russian knapweed gall midge, Jaapiella ivannikovi, was released at sites in Wyoming, Montana, and Colorado; a laboratory colony of the midge was established at CPHST Fort Collins in early 2010. A yellow toadflax-adapted strain of the Dalmatian toadflax stem weevil, Mecinus janthinus, was recently discovered in Montana. Field releases of the weevil have been made in Colorado, and a laboratory rearing effort was established at Colorado State University. (Contact Charla Hollingsworth)
Biological Control of Perennial Weeds Using Pathogens. Exotic perennial weeds are significant pests in a variety of settings throughout the Unites States. Among these weeds are Canada thistle (Cirsium arvense) and perennial pepperweed (Lepidium arvense), which are particularly invasive throughout much of the western US and reduce the grazing capacity and biodiversity of rangelands and natural areas. CPHST Fort Collins is working with international, federal, state, and university partners to survey for and develop biocontrol pathogens for these weeds. CABI Bioscience is conducting PPQ-funded surveys for potential biocontrol pathogens in Canada thistle’s native range in China. An unreported race of Albugo candida, a white rust pathogen, was identified through perennial pepperweed surveys in Colorado and California. Host specificity studies with the rust from both states are being conducted to determine their host range and efficacy. (Contact Charla Hollingsworth)