Harvest keeps moving right along and I keep hearing really good yields from across the county for both soybean and corn. It is not to say we haven’t seen some disappointments this year. In soybeans, some of our lower yielding fields may not all be due to weather.
It may actually be due to a pest we can’t see from above ground.
The pest is the Soybean Cyst Nematode (SCN) and it has been around for quite some time. According to Dr. Anne Dorrance, OSU plant pathologist with the College of Food, Agriculture and Environmental Sciences the state is “polluted” with SCN. Dorrance notes that fortunately many fields are at very low levels, which is where they should be kept. However, there are some surprising locations where individual fields are getting or have gotten into trouble with very high populations.
The following chart from Dr. Dorrance shows the levels of SCN and concerns:
• SCN egg Count/100 cc Cyst count Population Level
• 0-40 0 not detected
• 40-200 1 trace
• 200-2000 1-4 low
• 2000-5000 3-20 moderate
• 5000 & over 15-20 high
If your SCN report in the past has come back, Dr. Dorrance provides these suggestions:
1. Not detected: this is not surprising. Remember that SCN sits in pockets and can be quite variable (Figure 1). Continue to monitor your fields.
2. Trace: May begin to measure some yield loss on susceptible varieties, especially on lighter soils.
3. Low: Plant SCN resistant varieties or rotate to a non-host crop (corn or wheat).
4. Moderate: Rotate to a non-host crop and follow with SCN resistant varieties the following year. We have planted susceptible varieties in fields with this level of SCN and have recorded 20 to 50% yield loss.
5. High: rotate to a non-host crop for two to three years, then sample SCN to determine if populations have declined to a level where soybeans can be planted again.
SCN is picky about what it feeds and reproduces on but it does like a few weed hosts and cover crops as well as soybean. If you have SCN in your fields, it is important to also control winter annuals such as purple deadnettle, but also avoid cover crops such as several of the clover’s, cowpea and common & hairy vetch.
Now is the best time to sample! Dorrance and other specialists recommend sampling in the fall – because in most cases this is what the population will be in the spring. With the warmer weather this year and hopefully no frozen ground should give ample time to collect and process the samples in plenty of time for spring planting. Processing of samples does cost time and money, so here are a few thoughts on how to sample or how to target your sampling to get the best information for your money.
Through funds from the soybean check-off, Dorrance has completed several targeted surveys over the past 5 years. Her group tended to target those fields where yields were stuck or below 30 bu/A. Or when they sampled they hit those pockets in the field where the soybeans tended to be shorter or where they matured earlier and always yielded less that the rest of the field. Dorrance and others were able to detect SCN in almost all of these situations, so these are the ones that should have the top priority for sampling.
The following is an updated list of information on where to send the samples:
• OSU C. Wayne Ellett Plant and Pest Diagnostic Clinic, 8995 E. Main St. Bldg 23, Reynoldsburg, OH 43068. Phone: 614-292-5006. The web link is www.ppdc.osu.edu – follow this link to download forms to go along with the samples
• Brookside Laboratory Inc., 200 White Mountain Dr., New Bremen, OH 45869. Phone: 417-977-2766. The web link is www.blinc.com
• Locally we have Spectrum Analytic Inc., 1087 Jamison Rd. NW, Washington Court House, OH 43160. Phone: 740-335-1562. Their web link is www.spectrumanalytic.com
For some additional information on Management of SCN – always check Ohio’s SCN fact sheet and several other resources as well:
There is a great wealth of information pertaining to SCN at the following: http://soybeanresearchinfo.com/ – link to the 5th edition of the SCN guide developed through the North Central Soybean Research Program.
PQA meeting upcoming
Finally this week I want to let all pork producers know that I will be hosting a Pork Quality Assurance certification program this coming Tuesday, Oct. 20 at 7 p.m. at the Clinton County Extension Office, 111 S. Nelson Ave., Wilmington. Please call ahead of time at 937-382-0901 so we can have enough materials for everyone in attendance.
Tony Nye is the state coordinator for Small Farm Programs and an OSU Extension educator, agriculture and natural resources, for Clinton County and the Miami Valley EERA.
