A new soybean aphid (Hemiptera: Aphididae) biotype identified

Area of Science:

• Entomology
• Plant Breeding
• Pest Management

Background:

• Soybean aphid (Aphis glycines) is a major pest of soybean (Glycine max) in North America.
• Deployment of aphid-resistant soybean cultivars is a key sustainable management strategy.
• Concerns exist regarding the durability of resistance genes due to potential pest adaptation.

Purpose of the Study:

• To characterize the colonization of soybean aphid biotypes on different resistant soybean genotypes.
• To identify new soybean aphid biotypes capable of overcoming existing resistance genes.
• To assess the variability in virulence within North American soybean aphid populations.

Main Methods:

• Choice and nonchoice feeding tests were conducted.
• Soybean aphid isolates were tested on soybean plants with different resistance genes (Rag1, Rag2).
• Colonization success was evaluated to differentiate biotypes.

Main Results:

• A novel soybean aphid biotype, designated biotype 3, was identified.
• Biotype 3 readily colonized soybean plants possessing the Rag2 resistance gene.
• This finding indicates significant virulence variability in soybean aphid populations.

Conclusions:

• The emergence of biotype 3 capable of overcoming Rag2 resistance raises concerns about gene durability.
• High variability in soybean aphid virulence suggests rapid adaptation potential.
• Continued discovery of novel resistance genes and integrated pest management strategies is essential.