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.
