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United States Department of Agriculture

Agricultural Research Service

Research Project: Chemical Approaches to Eliminate Fungal Contamination and Mycotoxin Production in Plant Products

Location: Foodborne Toxin Detection and Prevention

Title: Conophthorin from almond host plant and fungal spores and its ecological relation to navel orangeworm: a natural products chemist's perspective

Author
item Beck, John

Submitted to: Journal of the Mexican Chemical Society
Publication Type: Review Article
Publication Acceptance Date: March 27, 2013
Publication Date: May 6, 2013
Repository URL: http://www.jmcs.org.mx/PDFS/V57/1/13.-%20Review.pdf
Citation: Beck, J.J. 2013. Conophthorin from almond host plant and fungal spores and its ecological relation to navel orangeworm: a natural products chemist's perspective. Journal of the Mexican Chemical Society. 57(1):69-72.

Interpretive Summary: The navel orangeworm (Amyelois transitella) moth is a major insect pest of California tree nuts – almonds, pistachios, and walnuts. During development from neonates to pupae, larvae of navel orangeworm feed upon the meat of these nuts causing physical damage, ultimately lowering kernel quality and bringing about significant monetary damage. The larvae have also been shown experimentally to transport aflatoxigenic fungal spores into the food product, and thus represent a serious food safety concern. Aflatoxins are toxic compounds produced by certain Aspergillus species. More specifically Aspergillus flavus and Aspergillus parasiticus are the fungi involved in contaminating California tree nuts. Odors emitted by plants the navel orangeworm develop on have played a large role in efforts to control or monitor navel orangeworm moths. For instance, a blend of almond host plant odors has recently been found to attract both male and female navel orangeworm moths during field trapping studies. The origin of many of the components within this host plant blend appears to be from the almond plant itself. However, new reports regarding the blend component, conophthorin – a chemical compound, imply a fungal origin for this particular odor. This perspective discusses current investigations directly related to the production of conophthorin, and proposes a new potential complex interaction among navel orangeworm, the almond host plant, and tree nut orchard fungi.

Technical Abstract: The navel orangeworm (Amyelois transitella) is a major insect pest that brings about significant monetary damage to California tree nuts – almonds, pistachios, and walnuts. During their development, larvae of navel orangeworm feed upon the meat of these nuts causing physical damage and ultimately lowering kernel quality. Moreover, the larvae have been purported to vectoraflatoxigenic fungi into the food product and thus represent a serious foodsafety concern. Aflatoxins are toxic metabolites produced by certain aspergilli – specifically for California tree nuts, Aspergillus flavus and Aspergillus parasiticus. Volatiles have played a large role in efforts to control or monitor navel orangeworm moths. For instance, a blend of almond host plant volatiles has recently been found to attract both male and female navel orangeworm moths during field trapping studies. The origin of many of the components within this host plant blend appears to be from the almond host. However, new reports regarding the blend component, conophthorin, imply a fungal origin for this particular volatile. This perspective discusses current investigations directly related to the production of conophthorin, and proposes a new relationship among navelorangeworm, the almond host plant, and ubiquitous tree nut orchard fungi.

Last Modified: 8/22/2014
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