In 2008, the economic loss for the soybean industry due to the presence of aphids was estimated to be approximately 4 billion U.S. dollars annually (Kim et al., 2016). Aphid infestation can decrease soybean yield as high as 50% (Wang et al., 1994; Ragsdale et al., 2007).  High aphid populations can reduce crop production directly when they are feeding, causing severe damage such as stunting, leaf distortion, and reduced pod set (Sun et al., 1990).  Although proper use of insecticides can greatly reduce the damaging effects of aphids on soybean yield, this approach is costly (∼33 U.S. dollars/hectare), detrimental for the environment, and can lead to the development of insecticide resistant aphids.  In addition, this practice could also adversely affect the population of insects that normally prey on aphids (Ragsdale et al., 2007).

Aphis glycines and a close relative A. gossipii are the only aphid species found colonizing soybean in the Unites States (Hill et al., 2004). To date, four soybean aphid biotypes are now known in relation to genes resistant to Aphis glycines, or Rag genes.  There are different resistance gene combinations (Rag 1, 2, and 3) from the soybean plant that offer tolerance to these pests, dependent on the soybean aphid type.

The use of soybean lines naturally resistant to aphids is a sound management approach to control soybean aphids. Scientists at the National Agricultural Genotyping Center (NAGC) have optimized high-throughput assays to screen soybean varieties for Rag 1, Rag 2, Rag 3 genes, each of which offers resistance to different aphid biotypes. By selecting the varieties that are resistant to the biotypes of aphids found in the field, farmers will decrease aphid damage and decrease yield losses due to aphids. Farmers can decrease insecticide use, thereby reducing costs and impact on the environment.

This project was funded in part by the North Dakota Soybean Council

References

Hill, C. B., Li, Y. & Hartman, G. L. 2004. Resistance to the Soybean Aphid in Soybean Germplasm. Crop Science, 44, 98-106.

Kim, C. S., Schaible, G., Garrett, L., Lubowski, R. & Lee, D. 2016. Economic Impacts of the U. S. Soybean Aphid Infestation: A Multi-Regional Competitive Dynamic Analysis. Agricultural and Resource Economics Review, 37, 227-242.

Ragsdale, D. W., McCornack, B. P., Venette, R. C., Potter, B. D., MacRae, I. V., Hodgson, E. W., O’Neal, M. E., Johnson, K. D., O’Neil, R. J., DiFonzo, C. D., Hunt, T. E., Glogoza, P. A. & Cullen, E. M. 2007. Economic threshold for soybean aphid (Hemiptera: Aphididae). J Econ Entomol, 100, 1258-67.

Sun, Z. Q., Tian, P. Z. & Wang, J. 1990. Study on the uses of aphid-resistant character in wild soybean. I. Aphid-resistance performance of F2 generation from crosses between cultivated and wild soybeans. Soybean Genetics Newsletter, 17, 43-48.

Wang, X., Fang, Y., Lin, Z., Zhang, L. & Wang, H. 1994. A study on the damage and economic threshold of the soybean aphid at the seedling stage. Plant Protection (Institute of Plant Protection, CAAS, China), 20, 12-13.