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ARS Home » Southeast Area » Fort Lauderdale, Florida » Invasive Plant Research Laboratory » Research » Research Project #441504

Research Project: Overseas Surveys and Testing for the Development of Biological Control Cogongrass (Imperata Cylindrica)

Location: Invasive Plant Research Laboratory

Project Number: 6032-22000-013-095-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jun 1, 2022
End Date: Sep 30, 2026

Cogongrass invades many subtropical and tropical areas and is estimated to infest over 500 million hectares world-wide. Asia is most likely the native range of cogongrass from where it was accidentally introduced to the US around 1912 in packing material from Japan. Cogongrass was later intentionally introduced for forage in Texas, Mississippi, Alabama, and Florida. Cogongrass is included in the federal noxious weed list and primarily invades the Gulf Coast states from Texas to Florida, Georgia, South Carolina, and Virginia. With climate change, this weed also has the potential to spread north to Oklahoma and Tennessee, and east to coastal North Carolina. Over 100,000 hectares are infested in Florida, Alabama, and Mississippi where cost of control may approach $ 400 per hectare. Cogongrass produces extensive rhizomes and seeds which allow it to spread, persist, and dominate invaded sites. The weed may reproduce vegetatively from rhizomes and is a prolific seed producer which allows wind dispersed invasion of new areas. Cogongrass leaves can grow to 1.2 to 1.5 meters in height and the plant can thrive in fire-based ecosystems. Although the weed was once thought to be suitable as food for cattle, the low nitrogen content, poor digestibility, and high silicate levels in the leaves deter grazing 1) Conduct biological control surveys for insects associated with cogongrass in Australia, Japan, and Indonesia 2) Curate and colonize collected insects from foreign surveys at USDA, Australia and USDA, Ft Lauderdale 3) Colonize and determine suitability of possible biological control agents of cogongrass at USDA, Australia and USDA, Ft Lauderdale

Here, we propose to develop safe and sustainable biological control of the invasive weed, cogongrass, one of the worst weeds worldwide and of disturbed areas of the southeastern US. Options to control this invasive weed are limited to two synthetic herbicidal compounds, glyphosate in natural areas and imazapyr in managed non-crop areas. This shortage of options raises concerns for the development of herbicide resistance. Further, the long-term success of control with these herbicides is highly variable, costly, and provide only temporary relief requiring annual repeat treatments. Additional causes for concern include human exposure to these pesticides and unintentional damage to non-target, valued plants. This project will develop ecologically safe, sustainable, and cost-effective control of cogongrass for forests and grasslands in the southeastern US through the development of biological control agents. 1) Conduct surveys in the area of origin of the weed, Japan, Indonesia, Australia 2) Colonize and curate the collections 3) Determine origin of invasive populations of cogongrass in the US through various molecular techniques 4) Determine safety of field release of biological control agents through quarantine host range testing