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, 2008). 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 their 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 resistance genes. Depending on the type of soybean aphid, there are different resistance gene combinations from the soybean plant that offer tolerance to these pests.
The use of soybean lines naturally resistant to aphids is another management approach to control soybean aphids. NAGC is developing a test to aid in characterizing the resistance genes present in the plants to offer a strategy for optimal deployment of aphid resistant soybean is also needed to ensure sustainability of this technology. By selecting the varieties that are resistant to the biotypes of aphids most prevalent in ND, farmers will decrease aphid damage and decrease yield losses due to aphids. Farmers will decrease insecticide applications reducing costs and impact on the environment.