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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #251835
Title: A possible novel black aphid control approach using plant growth regulators

Author
item Cottrell, Ted
item Wood, Bruce
item Ni, Xinzhi

Submitted to: Western Pecan Growers Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/5/2010
Publication Date: 3/8/2010
Citation: Cottrell, T.E., Wood, B.W., Ni, X. 2010. A possible novel black aphid control approach using plant growth regulators. In: Proceedings of the 44th Annual Western Pecan Growers Association Conference, March 7-9, 2010, Las Cruces, New Mexico. p. 16.

Interpretive Summary: The black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), elicits localized chlorotic injury to pecan foliage in order to feed, thereby accelerating leaf senescence and defoliation. Here we tested the action of certain plant growth regulators (i.e., forchlorfenuron, gibberellic acid and aviglycine), applied to orchard foliage with subsequent evaluation in the laboratory during 2006 and 2007, to prevent the black pecan aphid from triggering pecan leaf chlorosis and senescence-like processes. Additionally, we examined effects upon aphid mortality and development. Results indicate that foliage pretreated in the orchard with the combination treatment of “forchlorfenuron + gibberellic acid,” prior to being challenged by the black pecan aphid, resulted in much less aphid-elicited chlorosis than did control or aviglycine-treated leaf discs. No plant growth regulator affected aphid mortality; however, development time was increased by “forchlorfenuron + gibberellic acid” in 2006 and by the combination treatment of “aviglycine + gibberellic acid” on one date in 2007. Subsequent field trials confirm that application of certain plant growth regulators to pecan can mitigate chlorotic injury associated with black pecan aphid feeding.

Technical Abstract: The black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), elicits localized chlorotic injury to pecan foliage in order to feed, thereby accelerating leaf senescence and defoliation. The action of certain plant growth regulators (i.e., forchlorfenuron, gibberellic acid and aviglycine) to prevent the black pecan aphid from triggering pecan leaf chlorosis and senescence-like processes was evaluated. Treatments were applied to orchard foliage and used in laboratory leaf disc bioassays to assess possible reduction of aphid-elicited chlorosis and concomitant effects upon aphid mortality and development. Foliage pretreated in the orchard with the combination treatment of “forchlorfenuron + gibberellic acid,” prior to being challenged with aphids, resulted in much less aphid-elicited chlorosis than did control or aviglycine-treated leaf discs. No plant growth regulator affected aphid mortality; however, development time was increased by “forchlorfenuron + gibberellic acid” in 2006 and by the combination treatment of “aviglycine + gibberellic acid” on one date in 2007. Field trials confirm that application of certain plant growth regulators to pecan can mitigate chlorotic injury associated with black pecan aphid feeding. In conclusion, certain plant growth regulators possess the potential for usage on pecan to protect foliar canopies from the black pecan aphid via changes in the susceptibility of the host leaf to senescence-like factors being introduced by feeding black pecan aphids.