Location: Invasive Plant Research Laboratory
Project Number: 6032-22000-013-125-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2023
End Date: Sep 30, 2025
Objective:
Goals of invasive species management and the prevention, control and restoration using native plants. Here, we propose to develop safe and sustainable biological control of the invasive weed, cogongrass (Imperata cylindrica, a common weed of disturbed areas of the southeastern US. Cogongrass invasions in forests and grasslands constitute a significant challenge as resources are expended to control and restore invaded areas. Cogongrass is one of the ten worst weeds in the world, a US federally listed noxious weed, and one of the most problematic invasive weeds in the southeastern US. Cogongrass has broad impacts on native plant communities in terms of plant diversity and performance it aggressively competes with other vegetation for soil nutrients, alters the rates of decomposition of native grasses, and increases vegetative fuel loads while tolerating controlled burns. 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 proposal seeks funding to 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.
Objective 1: Conduct biological control surveys for insects associated with cogongrass in its native range, Africa, Australia, Japan, and Indonesia
Objective 2: Curate and colonize collected insects from foreign surveys at USDA, Australia and USDA, Ft Lauderdale
Objective 3: Colonize and determine suitability of possible biological control agents of cogongrass at USDA, Australia and USDA, Ft Lauderdale
Approach:
Here, we propose to use classical biological control to reunite coevolved natural enemies of cogongrass with invasive populations of the weed to reduce its invasiveness and reduce management costs. The Invasive Plant Research Laboratory (IPRL) in Fort Lauderdale, Florida has historically been an international leader in the development of classical biological control agents of weeds. Over the past 50 years, this lab has developed and introduced 26 biological control agents targeting 10 weeds. The process includes literature reviews, examination of genetic comparisons with molecular analysis to guide foreign exploration, elucidation of weed population dynamics, and surveys for potential natural enemies in the native range. The lengthiest part of the process is the intensive host range evaluations which are conducted under quarantine in our USDA-ARS-IPRL laboratory in Fort Lauderdale to determine the environmental safety of imported natural enemies. These results are reviewed by federal regulatory agencies (USDA-APHIS-PPQ; USFWS) and if they indicate the potential agent poses no significant risk to non-target species, a release permit will be issued. Release, establishment, and evaluation of the permitted agents are conducted to quantify their influence on plant performance. Effective agents and techniques are transferred to user groups to speed the deployment and adoption of biological control. Post-release monitoring, integration of control methods, and ecosystem restoration are the final steps in a multi-faceted approach to reducing impacts from problematic weeds in natural and managed systems.
Despite the many problems caused by this weed in the US and various parts of the world, no biological controls have been released against cogongrass. However, numerous biological control agents have been approved for other grasses, namely two species of Archanara for invasive Phragmites australis and a gall wasp and scale were released against Arundo donax. Several insect herbivores have been discovered feeding on cogongrass that need to be examined to determine their potential for safe and effective biological control.
