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United States Department of Agriculture

Agricultural Research Service

Research Project: PLANT RESISTANCE, BIOLOGY, AND RESISTANCE MANAGEMENT OF CORN PESTS, WITH EMPHASIS ON WESTERN CORN ROOTWORM

Location: Plant Genetics Research

Title: Capsules containing entomopathogenic nematodes as a Trojan horse approach to control the western corn rootworm

Authors
item Hiltpold, Ivan -
item Hibbard, Bruce
item French, Bryan
item Turlings, Ted -

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 6, 2012
Publication Date: August 31, 2012
Citation: Hiltpold, I., Hibbard, B.E., French, B.W., Turlings, T. 2012. Capsules containing entomopathogenic nematodes as a Trojan horse approach to control the western corn rootworm. Plant and Soil. 358:11-25.

Interpretive Summary: The use of nematodes in the biological control of soil insect pests is hampered by costly and inadequate application techniques. As a possible solution we evaluated an encapsulation approach that offers effective application and may possibly attract the pest by adding attractants to the capsule shell. The nematodes used have shown high levels of control in previous lab studies with the western corn rootworm. Nematodes were encapsulated in a polysaccharide shell derived from algae. Shells of varying thickness and composition were evaluated. Nematodes readily survived the encapsulation process and were able to break through the shell and subsequently infect western corn rootworm. The added attractants and feeding stimulants to the shell attracted the pest larvae as much as maize roots in the lab. In field trials, encapsulated nematodes were more effective in controlling western corn rootworm than those sprayed in water over the soil surface, but in these trials the addition of attractants did not increase the control efficiency. The study demonstrates that nematodes can be successfully applied in capsules in the field. Further improvements are needed to make the capsules a cost effective alternative to conventional field application of nematodes.

Technical Abstract: The use of entomopathogenic nematodes in the biological control of soil insect pests is hampered by the costly and inadequate application techniques. As a possible solution we evaluated an encapsulation approach that offers effective application and may possibly attract the pest by adding attractants to the capsule shell. Heterorhabditis bacteriophora nematodes, which show high virulence against the maize root pest Diabrotica virgifera virgifera, were encapsulated in a polysaccharide shell derived from the algae Laminaria ssp. Shells of varying thickness and composition were evaluated. Nematodes readily survived the encapsulation process and were able, varying with shell thickness and temperature, to break through the shell and subsequently infect hosts. The added attractants and feeding stimulants to the shell attracted the pest larvae as much as maize roots. In field trials, encapsulated H. bacteriophora nematodes were more effective in controlling D. virgifera virgifera than those sprayed in water over the soil surface, but in these trials the addition of stimulants did not increase the control efficiency. The study demonstrates that nematodes can be successfully applied in capsules in the field. Further improvements are needed to make the capsules a cost effective alternative to conventional field application of nematodes.

Last Modified: 12/21/2014