Having one pest can be damaging for soybean yields, but having two can be disastrous. According to a recent soy-checkoff-funded study, the presence of soybean aphids in a soybean field increases the chances that soybean cyst nematode (SCN) will reproduce in that field — even in the presence of SCN-resistant varieties.
Iowa State researchers recently completed field studies, and found that SCN reproduction increases when plants are co-infested with aphids. In fact, there was a 33% increase in a single generation of SCN compared with plants that were not infested with soybean aphids.
“SCN can reduce soybean yield by 50%, and our main tools of management are resistant varieties,” said Greg Tylka, a professor in the department of plant pathology and microbiology at ISU. “When the varieties we studied were infested by aphids, they lost their nematode resistance.”
While farmers are probably already aware of the strain SCN has on their soybean yield and bottom-line, most probably are not aware of how aphids are making the situation worse.
“Soybean farmers are already losing millions of dollars a year, in Iowa alone, from SCN,” said Mike McCarville, graduate research assistant in the department of entomology at ISU. “Aphids are compounding what is already a bad situation. Farmers who are struggling with nematodes might also be battling another pest that they weren’t even considering.”
With the discovery of these new issues, soybean farmers might have to look for alternative solutions.
“For years soybean farmers have been using resistant varieties as a solution for SCN, but they may have to start looking at other strategies,” said Matt O’Neal, assistant professor in the department on entomology at ISU. “They may have to use other forms of resistance, such as using varieties that are resistant to aphids.”
For more information on production research results, funded by the soy checkoff, visit UnitedSoybean.org.