New management resources focus on identifying hidden pests that can reduce soybean yields
ST. LOUIS — Soybean growers are being encouraged to use the weeks immediately following harvest to check fields for nematodes that may be quietly cutting yields.
Soybean cyst nematode remains one of the most damaging soybean pathogens in North America, but it isn’t the only nematode capable of causing problems. Root-knot, root lesion and reniform nematodes can also affect soybean production, depending on the region and field conditions.
One of the challenges for farmers is that significant damage can occur below ground without obvious signs in the soybean canopy. Soybean cyst nematode, for example, can reduce production substantially even when plants appear relatively healthy.
That makes soil sampling an important part of determining whether a field has a problem.
Fall provides growers with an opportunity to collect samples after the crop comes out and use those results when making seed and management decisions for the next growing season.
New Soybean Nematode Management Guides supported by soybean checkoff funding provide information on identifying and managing four major nematode threats: soybean cyst, root-knot, root lesion and reniform nematodes.
The guides include information on proper soil sampling, recognizing potential nematode damage and developing management plans based on the pest present in a field.
Management can vary because the different nematode species don’t behave the same way. Some also have broad host ranges, meaning rotating away from soybeans doesn’t necessarily eliminate the problem.
Research involving soybean farmers in southern production areas found soybean cyst and root-knot nematodes are relatively well recognized. Root lesion and reniform nematodes, however, aren’t as familiar to many producers.
The research also found some growers continue to depend heavily on visible crop symptoms when determining whether nematodes are present. That can allow infestations to go undetected because plants don’t always show obvious aboveground damage.
Once a field is infested, eliminating nematodes entirely generally isn’t realistic. Instead, specialists recommend using several management practices to keep populations under control and reduce yield losses.
Those options can include resistant soybean varieties, crop rotation where appropriate, nematode-protectant seed treatments and practices designed to maintain healthier root systems.
Weather can also influence the amount of damage. Fields dealing with drought or other environmental stress may suffer greater yield losses when significant nematode populations are also present.
For soybean growers preparing for harvest, specialists say the important first step is determining what’s actually in the field. Post-harvest soil testing can provide that information before decisions are made for the next crop.
The Soybean Nematode Management Guides are available digitally through The SCN Coalition.