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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #285533
Title: Can plant bioregulators be potential tools for managing black pecan aphids?

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

Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: 9/28/2012
Publication Date: 11/9/2012
Citation: Cottrell, T.E., Wood, B.W., Ni, X. 2012. Can plant bioregulators be potential tools for managing black pecan aphids?. Pecan Grower. 24(1):14-21.

Interpretive Summary: Plant bioregulators (PBRs) can have various effects on plants. Our research leads us to conclude that some PBRs could be used to protect pecan foliage from damaging chlorotic feeding injury elicited by the black pecan aphid. These PBRs are not insecticidal but do interfere with BPA feeding by inhibiting formation of chlorotic feeding zones on pecan foliage. In this study we evaluated treatments applied to orchard foliage which was subsequently used in laboratory leaf disc bioassays during 2006 and 2007 to assess possible reduction of aphid-elicited chlorosis and concomitant effects upon aphid mortality and development. Foliage pretreated with the PBRs “forchlorfenuron + gibberellic acid,” prior to being challenged with black pecan aphids, resulted in significantly less aphid-elicited chlorosis than did control or the PBR aviglycine-treated leaf discs. No PBR affected aphid mortality; however, development time was increased by “forchlorfenuron + gibberellic acid” in 2006 and by “aviglycine + gibberellic acid” on one date in 2007. We conclude that some PBRs possess the potential for usage on pecan to protect foliage from black pecan aphid feeding injury.

Technical Abstract: Some classes of plant bioregulators (PBRs) possess the potential for usage on pecan (Carya illinoinensis [Wangenh.] K. Koch) to protect foliar canopies from black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), feeding injury. The black pecan aphid elicits localized chlorotic injury to pecan foliage leading to faster leaf senescence and defoliation. Some PBRs may posess the ability to prevent M. caryaefoliae from initiating pecan leaf chlorosis and senescence-like processes. We evaluated treatments applied to orchard foliage and used in laboratory leaf disc bioassays during 2006 and 2007 to assess possible reduction of aphid-elicited chlorosis and concomitant effects upon aphid mortality and development. Foliage pretreated with “forchlorfenuron + gibberellic acid,” prior to being challenged with aphids, resulted in significantly less aphid-elicited chlorosis than did control or aviglycine-treated leaf discs. No PBR affected aphid mortality; however, development time was increased by “forchlorfenuron + gibberellic acid” in 2006 and by “aviglycine + gibberellic acid” on one date in 2007. Certain PBRs possess the potential for usage on pecan to protect foliar canopies from M. caryaefoliae via changes in the susceptibility of the host leaf to senescence-like factors being introduced by feeding aphids. This protective effect on host foliage, and associated suppressive effect on development of feeding aphids, might also be relevant to pest management programs on other aphid-crop systems in which aphid-elicited chlorosis and senescence-like processes can limit profitability.