Root-knot nematodes may have finally met their match. These hungry little microscopic worms love to munch on Georgia soybeans. So University of Georgia agricultural experts designed new nematode-resistant varieties.
Now it's up to Georgia farmers to match the right varieties to the nematode species flourishing in their fields.
"If you know what's in your field, you can pick the right variety," said Richard Davis, a nematologist with the UGA Extension Service. "But if you don't know, you have to plant varieties that are resistant to all the various species of root-knot nematodes. That greatly limits your selection."
Soybean farmers can submit soil samples and root samples with root-knot galls to the UGA agricultural lab through their county Extension Service agent.
The nematode test, which tells which species is in a field, normally costs $15 per sample. This fall, though, the Georgia Soybean Association is underwriting the tests to help farmers choose the right soybean varieties to resist the nematodes in their fields.
Farmers need to take samples before cold weather comes, Davis said.
"The best time to take soil samples is at or near harvest time," he said. "I know farmers get so busy it's hard to take the time to sample. But once cold weather sets in, the nematode population goes way, way down, and we may not find them in the sample."
Different species look similar under the microscope. So the scientists need to do much more specialized testing to tell them apart.
"We have a machine that analyzes the enzymes present in the female nematode," Davis said. "This is a much faster, more accurate and reliable way to determine species than previous methods."
The only problem is catching the nematodes at the right growth stage.
"If the nematodes are at the correct development stage, we can run the analysis," Davis said. "If not, we'll grow out the nematodes on tomato plants in our greenhouse and then run the test. It will take about six to eight weeks longer."
A farmer may not be sure he has root-knot nematodes or may have been growing resistant varieties already. Davis advises them to send in a soil sample. If the lab finds any nematodes, they'll run the analysis.
The county agent can show farmers how to sample and has other information on testing for nematodes. The results will go back to the agent, who will explain them to the grower.
"We're trying to fill the gap so new varieties can be more useful to soybean farmers," Davis said.
