ARS | Publication request: RELATIVE INHIBITION OF INSECT PHENOLOXIDASE BY CYCLIC FUNGAL METABOLITES FROM INSECT AND PLANT PATHOGENS

Submitted to: Natural Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 9, 2000
Publication Date: N/A

Interpretive Summary: Insects cause hundreds of millions of dollars of losses to crops each year in the U.S. alone. Most insect control measures presently involve the use of chemical pesticides, which are costly to apply and may cause undesirable environmental side effects. Insect pathogens are generally a safer and often lower cost control measure to use but are not widely accepted by growers due to their relatively low efficacy and slow kill rates. A series of relatively low-toxicity metabolites produced by insect fungal pathogens were evaluated for their ability to inhibit an enzyme from insects that they use to stop the growth of fungal pathogens. Some metabolites were found to be effective inhibitors of this enzyme. Development of fungal strains that produce the more effective fungal metabolites, through conventional means or genetic engineering, should lead to more effective insect pathogens that could be more widely utilized and result in more environmentally acceptable insect control.

Technical Abstract: The fungal metabolites kojic acid, fusaric acid, and picolinic acid all inhibited fall armyworm (Spodoptera frugiperda) hemolymph and cuticle phenoloxidase at 10**-3 M. Kojic acid was order of magnitude more active than fusaric acid and picolinic acid. Production of these compounds may allow related species of fungi to be pathogens of insects or plants due to their ability to inhibit similar defensive enzymes in both groups of organisms.