We have continued support to run assays and education sessions for farmers throughout the region to be
able to answer “What’s your number?”
There are fields throughout the Midwest, where not only are soybean cyst nematode numbers creeping up to
economic levels but also the reproduction factor, which is the ability to reproduce on the one source of
resistance (PI 88788) is also creeping up, according to Dr. Dorrance, Ohio State University pathologist.
The good news is that adaptation to the PI 88788 type of resistance towards SCN in soybean is going to be
slow – but it is happening in a couple of fields in Ohio where the number of cysts are up to 27 percent
of the susceptible check.
We received soil samples from 238 fields during 2018 and found 9 percent with moderate and about 5
percent with high SCN population levels.
And here are specific suggestions of where to sample to find SCN:
1. Review the yield maps and target those areas of the field where yields were low and you can’t explain
why. No flooding or weed outbreak.
2. Target fields with heavy purple dead nettle or other winter annuals that can SCN can reproduce on,
especially during a warm winter.
3. Target fields that are planted continuously to soybean or those where rotations are rare. Don’t forget
double crop situations in these fields. For full season soybeans, we can have 3 to 4 life cycles per
growing season depending on where your fields are in the state, with double crop soybean, there is time
for at least 2 life cycles, thus almost negating the effect of planting a non-host, where the
populations can drop by 50 percent.
Members of the American soybean Association were sent sample bags last May. And if you are like me, it is
probably still on your desk, so please take a look for that. If you are not a member, let your county
educator know – we will be shipping bags to each county educator in the next few weeks.
For more information- check out our SCN information at: OSU soybean diseases:
ttps://u.osu.edu/osusoybeandisease/
SCN Coalition: https://www.thescncoalition.com/
