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ARS Home » Midwest Area » Wooster, Ohio » Corn, Soybean and Wheat Quality Research » Research » Publications at this Location » Publication #301227
Title: Use of refuse in host plant resistance systems for the control of virulent biotype adaptation in the soybean aphid

Author
item WENGER, JACOB - The Ohio State University
item RAMSTAD, MONICA - The Ohio State University
item Mian, Rouf
item MICHEL, ANDREW - The Ohio State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2014
Publication Date: 8/15/2014
Citation: Wenger, J., Ramstad, M., Mian, R.M., Michel, A.P. 2014. Use of refuse in host plant resistance systems for the control of virulent biotype adaptation in the soybean aphid. Journal of Economic Entomology. 107(4):1599-1609.

Interpretive Summary: The soybean aphid is the number one pest of soybean in North America. Host plant resistant (HPR) soybean cultivars have the potential to offer economic control of the soybean aphid (Aphis glycines). However, virulent aphid biotypes capable of overcoming plant resistance have caused challenges for the integration of HPR. The widespread planting of HPR soybean would increase selection pressure favoring the proliferation of virulent biotypes, and decrease durability of aphid resistance soybean lines. An analogous situation occurs in managing insect resistance to transgenic Bt crops, where susceptible refuge planting effectively delays the evolution and spread of Bt-resistance. We investigated the efficacy of susceptible refuges in HPR soybean as a tactic to manage virulent soybean aphid biotypes. The virulent aphid biotype 3 and avirulent aphid biotype 1 were reared in greenhouse microcosms replicating a several refuge size and HPR gene scenarios, allowing us to discern how the presence of a refuge alters the relative fitness and movement of biotypes in isolation and in competition. The virulent biotype had greater fitness in 10 of 12 tested microcosms, with the greatest advantage observed when refuge was lacking. Compared to pure resistance, refuges significantly reduced the fitness of virulence, as the avirulent biotype preferentially moved to and utilized refuge plants. Competition between biotypes favored the virulent biotype but had no effect on the avirulent biotype. While susceptible refuges may not reverse the proliferation of virulent biotypes, they could slow the spread of virulence by sustaining the avirulant soybean aphids.

Technical Abstract: Host plant resistant (HPR) soybean varieties have the potential to offer economic control of the soybean aphid (Aphis glycines). However, virulent aphid biotypes capable of overcoming plant resistance have caused challenges for the integration of HPR. The widespread planting of HPR soybean would increase selection pressure favoring the proliferation of virulent biotypes, and decrease HPR durability. An analogous situation occurs in managing insect resistance to transgenic Bt crops, where susceptible refuge planting effectively delays the evolution and spread of Bt-resistance. We investigated the efficacy of susceptible refuges in HPR soybean as a tactic to manage virulent soybean aphid biotypes. The virulent biotype 3 and avirulent biotype 1 were reared in greenhouse microcosms replicating a variety of refuge size and HPR gene scenarios, allowing us to discern how the presence of a refuge alters the relative fitness and movement of biotypes in isolation and in competition. The virulent biotype had greater fitness in 10 of 12 tested microcosms, with the greatest advantage observed when refuge was lacking. Compared to pure resistance, refuges significantly reduced the fitness of virulence, as the avirulent biotype preferentially moved to and utilized refuge plants. Competition between biotypes favored the virulent biotype but had no effect on the avirulent biotype. Our findings suggested that while susceptible refuges would be incapable of reversing the proliferation of virulent biotypes, they could slow the spread of virulence by maintaining avirulence.