Photo by Paul David Blakeley. © Copyright 2005. All Rights Reserved.

Approaches used to control weeds include biological, chemical, cultural, mechanical, and prescribed burning procedures. Integrated Pest Management, a combination of two or more of these options, is usually preferable.

Biological control agents are insects or other organisms that are intentionally introduced to reduce plant pests or weeds to acceptable levels. The USDA Animal and Plant Health Inspection Service regulates these agents, which are imported under PPQ Form 526 permit into high-security containment facilities. An interagency Technical Advisory Group reviews petitions and there is public notice in the Federal Register for comment before release into the environment. Concerns include impact on crops and other plants including endangered and threatened species.

Biocontrol agents weaken target plants and reduce seed production. This may be a cheaper approach to control large infestations where a low population of the weed is acceptable. Disadvantages include the high cost of finding and testing potential control organisms, lack of effective agents specific to target weeds, inability to establish in some areas, and failure to eradicate the target weed.

Insects have been released in the U.S. to help control infestations of noxious weeds including hydrilla, giant salvinia, leafy spurge, melaleuca, purple loosestrife, tropical soda apple, and yellow star thistle.

The USDA Agricultural Research Service, U.S. Forest Service, North Carolina State University, and others have looked for agents to control kudzu in China and the U.S. Kudzu is not a problem in China because the roots are dug and ground into starch for food. Several species of beetles feed on leaves and roots, but studies on these have not been completed.

At least two plant diseases in the U.S. have been found to kill kudzu during experiments. but more testing, practical production procedures, and approvals are needed. It appears that these are bioherbicides which must be applied directly on the target weed and do not reproduce.

In summary, we currently have no known biological control agent to kill kudzu.

Arthur E. Miller
Regional Program Manager, USDA-APHIS-PPQ (Retired)
Raleigh, NC

The above includes information produced by the USDA Animal and Plant Health Service and the Weed Science Society of America.

Dr. Ted D. Center (USDA Agricultural Research Service, Invasive Plant Research Laboratory, 3225 college Avenue, Davie, Florida, 33314, reported at a conference during May 2005 that nothing currently looks promising for biocontrol of kudzu. Ted presented a paper entitled "Biological control: What is underway and what is possible and impossible". Our understanding is "Donít hold your breath, it isnít going to happen in our lifetime."

Dr. Mark Weaver provides a general introduction to kudzu biocontrol, with citations to more recent information in Kudzu Biocontrol (34 KB PDF).

Coalition volunteer Dr. Gillian Newberry observed a kudzu pest that endangers a valuable food crop.

Dr. David B. Orr of North Carolina State University has studied insect feeding on kudzu in the U.S., as well as in its original habitat in China. Both U.S. stinkbugs, and China's native stinkbugs, eat most kudzu seeds in the pod before the plant can release them. However, seed distribution contributes little to kudzu propagation: Quickly growing vines form roots at their nodes, and thereby rapidly establish independent plants. Nevertheless, his publications on kudzu offer various possible avenues for biocontrol of kudzu.

Plant pathologist Dr. C. Doug Boyette of the Southern Weed Science Research Unit at the National Biological Control Laboratory (Stoneville, Mississippi) and his research group are testing a fungus that infects kudzu.

A kudzu-eating insect was identified by researchers at the University of Georgia and Dow AgroSciences. It was observed in northeast Georgia, where it is a pest of legume crops. It is native to India and China, and is a distant relative of stinkbugs.

Revised November 2009