Allen County Crop Scouting Update – Late July

Clint Schroeder – OSU Extension

As both corn and soybeans have entered the reproductive phase of the crop cycle it is an important time to be scouting for disease and insect issues. One of the most important parts of integrated pest management (IPM) is crop scouting. When done properly it can help farmers obtain higher yields and increased profit per acre. When heading to the field don’t forget your copy of the Corn, Soybean, Wheat, and Forages Field Guide to help determine identification and threshold levels for each disease or pest. The field guide can be purchased at the extension office if you do not already have a copy.


OSU Extension conducts weekly monitoring of Western Bean Cutworm (WBC) pheromone traps throughout the state and published the data in the weekly in the C.O.R.N. Newsletter. Those results can be found here. Trap numbers have remained low for Allen County, but there has been an uptick in surrounding counties. Now is the time to scout for egg masses on the upper leaves. Select 20 consecutive plants in 5 locations of the field. If over 5% of those plants have egg masses an insecticide application is warranted. Continue reading

Soybean Cyst Nematode Testing Available

Soybean cyst nematode (SCN) was first identified in Ohio in 1981, and has now been found in 72 of Ohio’s 88 counties, including Allen. SCN is a small roundworm parasite that damages soybeans by feeding on roots, robbing the plants of nutrients, and providing wound sites for root rotting fungi to enter. The severity of symptoms and yield losses are dependent on several factors including: the number of nematodes present in the field at planting, the soybean variety, tillage practices, soil texture, fertility, pH, and environmental conditions during the growing season. Seed producers worked to breed varieties with resistance to SCN initially, but now certain populations are becoming resistant to the resistance.

The SCN Coalition was developed with funding from the soybean checkoff to raise awareness among farmers. The goal of this group is to decrease SCN populations and increase yield potential for soybean farmers. As part of this effort OSU Extension in Allen County is looking for producers who will allow their fields to be sampled by extension personnel. There is no cost to the farmer for this program and all data will be kept confidential. If you are interested in having your fields sampled please call 419-879-9108 or e-mail Clint Schroeder at

Lookout for Spider Mites.

With continued dry weather, spider mites are one of the main pests to remain vigilant about in field crops.  They will often show up in field borders first as they move in from other habitats, for example if nearby ditches have been mowed.  Spider mites are difficult to see.  Look for injury signs — yellow spotting or stippling on the upper side of leaves.  In soybean this damage usually begins in the lower canopy and progresses upward as the mite population increases.  Heavily infested leaves may also have light webbing similar to spider webs.

Soybean leaves showing speckling.

There are no number-based thresholds available for mites, in part because counting them is not practical in a scouting context.  During drought populations can increase rapidly so scouting every 4 to 5 days in recommended during drought conditions.  Walk a broad pattern in the field and examine at least two plants in each of 20 locations.  Use the following scale developed by the University of Minnesota to evaluate spider mite damage in soybean, with treatment recommended at level 3.  There are relatively few products available for the treatment of two-spotted spider mites and some pyrethroid insecticides may actually “flare” spider mite populations, making them worse. Continue reading

How does flooding affect soybean germination?

The recent heavy rains have created flooded conditions in many areas of Michigan and producers need to understand how the standing water will affect their soybean fields. There is a lot of information available regarding the effects of flooded or saturated soils on emerged soybeans and this information is summarized in the Michigan State University Extension article, “Assessing water damage to emerged soybeans.”

Photo by Paul Gross, MSU Extension.

There is less information about how flooding affects the germination of recently planted soybean seed. A 2001 journal article, “Flooding and temperature effects on soybean germination,” by Wuebker et al. is a commonly cited reference on this topic. The research was conducted in a growth chamber so that temperature, timing of the flooding and the duration of the flooding could be controlled and varied. The researchers looked at two temperatures, 59 and 77 degrees Fahrenheit, three timings, one, two and three days after imbibition (seed swell or 12 hours after planting) and five durations of flooding ranging from 1 hour to 48 hours.

Temperature effects

The researchers found that overall, flooding adversely affected germination more severely at 59 F than at 77 F. This was true regardless of the duration of the flooding. They also showed that damage was reduced by warmer soil temperatures when the flooding occurred one to two days after imbibition. At 59 F, flooded conditions lasting for only 1 hour reduced germination rates by 22%. Continue reading

Help OSU Extension Document the Yield Impacts of the 2019 Planting Delays

By: CFAES Ag Crisis Taskforce

Normal planting dates for Ohio range from mid-April to the end of May. This season was quite different when planting for both crops was delayed until late May and stretched into June and even July across many parts of Ohio. We found ourselves grasping for any information we could find including 1) how much of an effect late planting dates would have on yield, and 2) what, if anything, we should change in management of these late planted crops. The historical planting date information we did have was somewhat helpful, but we did not have any data on what could happen when planting is delayed into the second half of June nor July. Continue reading

Soybean Cyst Nematode Sampling

By:  Stephanie Karhoff OSU Extension

A female soybean cyst nematode, stained with a bright pink stain, has set up her feeding site within the soybean root. Her body will fill with eggs and become a bright white cyst visible on the soybean root.

A female soybean cyst nematode, stained with a bright pink stain, has set up her feeding site within the soybean root. Her body will fill with eggs and become a bright white cyst visible on the soybean root. Photo: OSU Extension.

Soybean cyst nematode (SCN), Heterodera glycines, is a small roundworm that parasitizes soybean roots, stealing vital nutrients from the plant. Even if you are not seeing above-ground symptoms, SCN is likely still reducing your yield. To make matters worse, certain SCN populations are now becoming “resistant to the resistance.”  In other words, a portion of the nematodes now have the capability of feeding and reproducing on soybean varieties previously thought to be resistant. The main reason for this, is that more than 95% of all SCN-resistant varieties for the past two decades included resistance gene(s) from the same breeding line, Plant Introduction (PI) 88788. Just like herbicide-resistant weeds, relying on the same SCN resistance source for the past 20 years has led to SCN populations adapting to, and overpowering the resistance. Continue reading

Allen County Weed Survey

By Clint Schroeder OSU Extension

Each fall Ohio State University Extension conducts a survey of the different types of weeds present in soybean fields, as well as, the level of infestation. Weed Science State Specialist Dr. Mark Loux leads this study and uses the information gained to help develop future weed management programs. This study is conducted in each county where there is an Ag and Natural Resources Educator. The educator selects a route 80-100 miles long through the county and takes notes on one soybean field in each mile.

Allen County 2019 Weed Survey Results

Continue reading

What’s in your Grain Dust?

By Dr. S Dee Jepsen, State Leader of the OSU Extension Agricultural Safety & Health Program

As many farmers know, grain dust contains more than meets the eye. Moreover, the dust you inhale may also contain microbes, insects, and additional plant fodder. All of which are affected by temperature and humidity fluctuations. It is important to better understand what is in your grain dust, since many biological contaminants have been linked to health conditions like asthma and chronic bronchitis. That is why the OSU Extension Agricultural Safety & Health Program wants to sample your grain dust during a loud out period. See below for study details:

  1. We know your schedule is ever-changing, that’s why students will be available both weekdays/nights and weekends for sampling. A half day notice will suffice to allow for travel time
  2. Samples may be taken of multiple bins, storing different grains
  3. No preparation is needed for sampling!
  4. Sampling will not interfere with the load-out process.
  5. Measurements will only be taken during the unloading process.
  6. You will receive a dust analysis report ~1 week later showing the amount of Total Dust and Respirable Dust. Results are anonymous, and will not be shared with any other agencies.
  7. There is no fee for this service, and no incentives to participate, besides contributing to our understanding of dust level exposure. N-95 respirators are available upon request.

If you are interested in participating, please contact Dee Jepsen by phone at 614-292-6008 or by e-mail at

Frogeye Leaf Spot – Is It Worth Spraying in 2019?

By:  Anne Dorrance, Ohio State University

Frogeye leaf spot

Several reports over the last two weeks of heavy frogeye leaf spot pressure in some fields as well as low to moderate pressure in others.  This disease will continue to increase and infect new foliage as it develops on these late planted soybeans. Based on our previous research, only once (2018) in 14 years of studies did applications at the soybean growth stage R5 contribute to preserved yield.  At the R5, the leaf at the terminal is fully developed and the pods at any one of the top four nodes is fully expanded, but the seeds are just beginning to expand.

Soybeans that have frogeye and have just begun to flower, are at full flower, or have just reached the R3 growth stage, these decisions are going to be challenging.  In full disclosure, we don’t have data or examples to rely on here.  This late planting and late development is all new territory for all of us.  But there are some sound principles to rely on.

For soybeans that are in the R3 growth stage, pods are tiny, 3/16 of an inch at one of the four uppermost nodes of the plant. This is the time if frogeye leaf spot can easily be found in the canopy, a lesion on one plant every 40’ has in our studies, preserved yield in a normal growing season.  This growth stage in Ohio typically occurs in mid to late July on May planted soybeans.

So here are the questions to address for 2019 and in the order of importance.

  1. The value of the crop – are these soybeans grown for seed, then yes error on the side of caution and apply the fungicide and make a second application 14 days later.
  2. Are these soybeans under contract, and will you actually be able to sell them? If the answer is no, then adding more inputs into the crop may not be a sound investment.
  3. Will the soybean finish making grain before harvest? This question will most likely affect soybeans that are just now in full flower, we are hoping for a very long fall, but this will impact the return on applying the fungicide.
  4. How susceptible is the variety? For some resistant varieties, the frogeye leaf spots are small and only a few will form on each leaf.  So double check with your seed supplier to look at the ratings. In any event your seed dealer will want to watch this variety and work with their breeders.

If you do decide to spray, please leave unsprayed check strips – at least 3 separate locations in the field and collect the yield off each of these separately, the same is true for the fungicides sprayed strips, collect the data from these as well.  The yield maps will be especially important this year.  Secondly, choose the cheapest triazole fungicide that you can find.  This is going to be very important for the economic viability of this year’s crop. Also remember, we have detected QoI resistance in Ohio, and it is not advisable to spray these types of fungicides at these late dates on crops that are further behind in development.

If you don’t spray, and it is a highly susceptible variety, the disease will continue to increase on the plants, but only if periodic rains and heavy dews or fogs continue through the remainder of this crazy field season. Mark this field and this variety. These are important considerations for 2020 field season as this disease does now overwinter in Ohio. Replanting in the same field with the same variety or one that is susceptible to this disease is a recipe for further yield loss in the future.

Frogeye leaf spot