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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGICAL CONTROL OF INSECTS AND MICROORGANISMS TO PREVENT MYCOTOXIN CONTAMINATION Title: Comparison of volatile emissions from undamaged and mechanically damaged almonds

Authors
item Beck, John
item Merrill, Glory
item Higbee, Bradley - PARAMOUNT FARMING CO
item Roitman, James - ARS (RETIRED)

Research conducted cooperatively with:
item Paramount Farming Company, Llc

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 28, 2007
Publication Date: April 14, 2008
Citation: Beck, J.J., Higbee,B.S., Merrill, G.B., Roitman, J.N. 2008. Comparison of volatile emissions from undamaged and mechanically damaged almonds. Journal of the Science of Food and Agriculture.88(8):1363-1368

Interpretive Summary: Navel orangeworm (NOW) Amyelois transitella (Walker) is a major insect pest of almonds causing considerable monetary setbacks for both growers and processors in California and abroad, and thus control of NOW is one of the top priorities for the almond industry. Field observations report that the female NOW is attracted to previously injured almonds. Accordingly, our labs investigated the volatile output of damaged almonds in an effort to identify potential attractants for further studies into the control and/or monitoring of NOW. Mature almonds from the Monterey variety were evaluated for their volatile composition after mechanical damage and compared to the volatile composition of undamaged almonds. Volatiles were collected on Tenax, desorbed, and identified via gas chromatography and mass selective detector analyses. Volatiles unique to the damaged tree nuts included trace amounts of 3-pentanol and isolmers of the spiroketal chalcogran. Volatiles that increased in relative amounts after damage include the spiroketal conophthorin, numerous four-carbon ester, ketone, and alcohol derivatives, in addition to two eight-carbon chain compounds. Several volatiles, both unique and in increased amounts, were identified from damaged almonds. Their presence in damaged almonds warrants further investigation into their role in NOW response to damaged almonds, and may lead to insights in the control and/or monitoring of NOW.

Technical Abstract: BACKGROUND: Navel orangeworm (NOW) Amyelois transitella (Walker) is a major insect pest of almonds causing considerable monetary setbacks for both growers and processors, and thus control of NOW is one of the top priorities for the almond industry. Field observations purport NOW is attracted to previously injured almonds. Accordingly, our labs investigated the volatile output of damaged almonds in an effort to identify potential attractants for further studies into the control and/or monitoring of NOW. Mature almonds from the Monterey variety were evaluated for their volatile composition after mechanical damage and compared to the volatile composition of undamaged almonds. RESULTS: Volatiles were collected on Tenax, desorbed, and identified via GC-MS analyses. Volatile unique to the damaged tree nuts included trace amounts of 3-pentanol and isomers of the spiroketal chalcogran. Volatiles that increased in relative amounts after damage include the spiroketal conophthorin, numerous four-carbon ester, ketone, and alcohol derivatives, in addition to two eight-carbon chain compounds. CONCLUSION: Several volatiles, both unique and in increased amounts, were identified from damaged almonds. Their presence in damaged almonds warrants further investigation into their role in NOW response to damaged almonds, and may lead to insights in the control and/or monitoring of NOW.

Last Modified: 11/28/2014
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