2021 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.

A total of 82 soybean fields were observed in Allen County this year.  Waterhemp and volunteer corn were the most prevalent and present in 30% of the observed fields.

2021 Allen County Weed Survey Results

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Five Things to Know about Fall Herbicide Treatments

By:  Mark Loux OSU Extension

There is plenty of information on fall herbicide treatments in the C.O.R.N. newsletter archive and on other university websites.  Our philosophy on this has not changed much over the past decade.  A few brief reminders follow:

1.  When to spray?  Anytime between now and Thanksgiving will work, and possibly later.  We have applied into late December and still eventually controlled the weeds present at time of application.  Once hard freezes start to occur, there is usually a substantial change in the condition of certain weeds, such as dandelion and thistle, that renders them less sensitive to herbicides.  We discourage applications during periods of very cold weather which can occur starting about Thanksgiving, and also (obviously) when the ground is snow-covered. Continue reading

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.

Corn

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 schroeder.307@osu.edu

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

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