|Quisenberry, Sharron - VIRGINIA POLYTECH INST|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 30, 2005
Publication Date: December 27, 2005
Citation: Ni, X., Quisenberry, S.S. 2005. Diuraphis noxia and Rhopalosiphum padi interactions and their injury on resistant and susceptible cereal seedlings. Journal of Economic Entomology. 99:551-558. Interpretive Summary: Although cereal aphid resistance has been examined extensively for an individual aphid species, the interspecific interactions among cereal aphid species and multiple aphid resistance among cereal genotypes are still not well understood. This study examined the interspecific interactions between leaf chlorosis-eliciting Russian wheat aphid (RWA) and non-chlorosis-eliciting bird cherry-oat aphid (BCOA) and their injury on four cereal genotypes that confers different degrees of RWA resistance. In addition to confirming RWA resistance among the cereal genotypes and indicating that the RWA-resistant cereal genotypes did not confer BCOA resistance, the study demonstrated that simultaneous infestations of both aphid species caused an antagonistic effect on RWA population development, but not on BCOA, and non-chlorosis-eliciting BCOA synergistically enhanced the RWA–elicited leaf chlorophyll loss.
Technical Abstract: Interspecific interactions between the symptomatic (chlorosis-eliciting) Russian wheat aphid [Diuraphis noxia (Mordvilko)] and the asymptomatic (non-chlorosis-eliciting) bird cherry-oat aphid [Rhopalosiphum padi (L.)] on four cereal genotypes were examined by simultaneous infestations. Four cereals (i.e., Diuraphis noxia-susceptible 'Arapahoe' wheat and 'Morex' barley, and D. noxia-resistant 'Halt' wheat and 'Border' oat) and four infestations (i.e., control, D. noxia, R. padi, D. noxia/R. padi) were used in the research. While D. noxia biomass confirmed D. noxia resistance among the cereal genotypes, R. padi biomass indicated that the D. noxia-resistant cereal genotypes did not confer R. padi resistance. Simultaneous infestations of both aphid species caused an antagonistic effect on D. noxia population development, but not on R. padi. Diuraphis noxia biomass was significantly lower in D. noxia/R. padi infestation than that in D. noxia infestation on all cereals, except Border oat. All aphid infestations caused a significant plant biomass reduction in comparison with the control. In comparison with D. noxia infestation, D. noxia/R. padi caused a significant plant biomass reduction on all cereal genotypes, except Morex barley. Although D. noxia biomass from D. noxia/R. padi infestation was significantly less than that in D. noxia infestation, net leaf chlorophyll and plant biomass loss in D. noxia/R. padi was the same as in D. noxia infestation, which suggested that the asymptomatic R. padi synergistically enhanced the D. noxia–elicited leaf chlorophyll loss. The coexistence of R. padi (a senescence feeder) in D. noxia (a flush feeder)-elicited chlorotic leaf lesions in D. noxia/R. padi infestation suggested that the D. noxia-elicited chlorosis is the result of the accelerated leaf senescence process.