Author
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Beck, John |
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Merrill, Glory |
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HIGBEE, BRADLEY - PARAMOUNT FARMING CO |
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ROITMAN, JAMES - ARS (RETIRED) |
Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/28/2007 Publication Date: 4/14/2008 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. |