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United States Department of Agriculture

Agricultural Research Service

Title: Compatibility of Photoactive Dyes with Insect Biocontrol Agents

Authors
item Martin, Phyllis
item Mischke, Barbara
item Schroder, Robert

Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 1998
Publication Date: N/A

Interpretive Summary: Often germs, or microbes, which kill or weaken insects are better alternatives to controlling insects than chemicals. But sometimes, microbes alone cannot protect crop plants from the insect pests that eat them. A pink dye, found in some over-the-counter medicines, has been shown to kill insects in bright sunlight. Would such a dye be able to be used in combination with insect-killing microbes? insect-killing microbes? The answer is no, not when mixed together. This dye stops the microbe from affecting the insects. These two methods of killing insects could be used in sequence by people who apply pesticides, microbes or chemicals for pest control.

Technical Abstract: Integrated Pest Management (IPM) programs often look for environmentally friendly ways to control pests. Biological control agents such as the bacterium, Bacillus thuringiensis Berliner, and the fungus, Beauveria bassiana (Balsamo) Vuillemin, can control insects with minimal environmental impact. Often these agents alone cannot prevent yield loss or are too expensive. We looked at the in vitro combination of these agents and phloxine B (red dye D&C 28), an FDA approved dye with the intent to provide better insect control. Phloxine B and related xanthene dyes inhibited the growth of both B. thuringiensis and B. bassiana. This inhibition increased with increasing concentration and light intensity. Therefore we would expect a adverse effect on the field performance of these biological control agents in combination with xanthene dyes. Preliminary field results support this conclusion.

Last Modified: 10/30/2014
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