Soybean aphids may be small, but they find strength in numbers. With a common economic threshold of 250 aphids per plant, farmers could easily see scenarios where a 100-acre field could literally house billions of this pest.
Current chemical solutions are on the market, but timing can be tricky. In fact, the University of Nebraska-Lincoln and others note that applying too early can be a waste of time and money. Natural predators abound, but getting ladybirds, parasitic wasps and others delivered isn’t typically seen as effective. (Note – drones may be a game-changing technology in this arena, if this University of Queensland project takes off.)
Researchers are hoping for another game-changing tool in the form of new resistant varieties, too. The North Central Soybean Research Program (NCSRP), has several projects in the works, including discovering new aphid-resistant traits and breeding new aphid-resistant varieties.
"The desired outcome of our work is to increase profitability and sustainability for soybean farmers and to provide unbiased information to help them with their management decisions," says Kelley Tilmon, associate professor and soybean extension specialist at South Dakota State University.
Tilmon says researchers are looking at how two traits, Rag1 and Rag2, could be stacked in a “gene pyramid” that could perform as good or better than current insecticides on the market.
“I think it could be a game-changer for aphid management,” Tilmon says. “There are several other genes in the pipeline, so triple pyramids are possible, too. There’s no reason these varieties can’t be high agronomic performers.”
Tilmon adds there is no “silver bullet” solution for soybean aphids, but is enthusiastic by the current progress. Other area entomologists are in agreement.
“Growers shouldn't rely on a single method of pest management and should continue to scout fields thought to be resistant,” notes Tom Hunt, Extension entomologist with University of Nebraska-Lincoln.
In the video below, Hunt explains why improved varietal performance against soybean aphids could have several benefits, including not taking “such a hard [yield] hit” in instances where insecticide applications were delayed.