C.O.R.N. Newsletter: 2023-36

Summary

The weather pattern over the last couple of weeks has certainly brought cooler temperatures to the region. However, temperatures are still above average across the state through the first 16 days of October. In fact, most locations across the northern half of Ohio typically experience their first 32°F (freeze) in the first two weeks of the month. As Figure 1 shows, this is not the case in 2023, with only a couple of stations having reported freeze conditions so far.

Despite widespread rainfall this past week, with many sites picking up 0.5-1.5” of rain, precipitation is still running 25-75% of normal across the bulk of the state. As of Thursday October 12, 2023, 97% of the state was described as abnromally dry and about 46% of the state was experiencing moderate drought conditions according to the U.S. Drought Monitor. Cooler temperatures and any moisture should help to slowly improve conditions over the next few weeks to months, but with the strong likelihood of El Niño conditions persisting through winter, we will need to watch the progress of soil moisture recharge closely throughout winter. For more information, check out the State Climate Office and sign up for our monthly and quarterly climate summaries.

Forecast

We are starting the week off with northerly flow and a few scattered lake effect rain showers across the state on Monday. These should diminish throughout the day on Tuesday, leaving drier weather and a modest warming trend for Tuesday and Wednesday. Highs should recover into the 60s for much of the week, ahead of low pressure that is expected to move through the Great Lakes region on Thursday through Saturday. This system will drag a series of cold fronts through with rain showers and breezy conditons to end the week. Temperatures will drop back into the 50s for daytime highs over the weekend, but clouds should keep overnight lows from falling too low. Clearing skies Sunday and Monday night next week could create a scenario for a more widespread freeze event however. The current forecast shows anywhere from 0.10” NW to as much as 1.5” across eastern Ohio over the 7 days (Figure 2).

The Climate Prediction Center’s 8-14 Day Outlook and the 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Center indicate that above average temperatures are likely for Ohio with precipitation leaning toward above average for the period of October 24 – 30, 2023 (Figure 3). For this time of year, the average high-temperature range is 61-66°F, the average low-temperature range is 41-45°F, and the average weekly total precipitation is 0.55-0.75 inch.

Harvest is progressing in much of Ohio, though recent rains have slowed field activities in some areas. As crops continue to come off it’s a good time for a reminder about the value of fall-applied herbicides. Rains this past week may stimulate winter annual weed emergence to some extent. This is the best time of year to control winter annuals and some of the more difficult to manage overwintering weed species. Biennial and perennial plants are now sending nutrients down to the root systems in preparation for winter. Systemic herbicides like glyphosate and 2,4-D applied at this time will be translocated down into the roots more effectively than if applied in spring when nutrients are moving upward. This results in better control. In addition, the increasingly unpredictable spring weather patterns we have experienced in recent years can influence the timing and efficacy of spring burndown applications. Fall-applied herbicides can lead to weed free situations going into spring until early emerging annuals begin to appear in April, and are an essential component in the control of marestail and other overwintering species.

Here are some reminders when it comes to fall-applied herbicides:

• Evaluate weed emergence and growth post-harvest to help determine if an application is necessary.

• Fall-applied herbicides should primarily target weeds that are emerged at the time of application.
• Species present in large quantities late-season that would necessitate the application of an herbicide include (but are not limited to): marestail, dandelion, wild carrot, poison hemlock, common chickweed, purple deadnettle, henbit, annual bluegrass, and cressleaf groundsel.
• OSU research has not found much of a benefit from adding metribuzin or other residual products late in the fall. The exception to this is chlorimuron, which can persist into the spring. The recommendation here has generally been to keep costs low in the fall and save those products for spring when you will get more bang for your buck.
• Herbicides generally work across a range of conditions, though activity can be slower as temperatures drop. Foliar products are most effective when daytime temperatures are in the 50s or higher and nighttime temperatures remain above 40.

Table 1 in the Weed Control Guide for Ohio, Indiana, Illinois, and Missouri provides ratings for various overwintering weed species in response to fall-applied herbicides. For questions related to the identification and control of weeds, reach out to Alyssa Essman at Essman.42@osu.edu.

Registration is open for the 2nd annual Ohio State Organic Grains Conference, January 4-5, 2024 at the Maumee Bay Lodge and Conference Center near Toledo, Ohio. The 2024 conference offers programming for experienced organic growers, growers transitioning to or considering organic, and consultants or educators who support these growers. Featured speakers will include Klaas Martens from Lakeview Organic Grain in New York; Léa Vereecke from Rodale Institute; former Ohio State soil fertility specialist Steve Culman; and Eugene Law, currently of USDA-ARS, but soon to be an Ohio State assistant professor in weed ecology.

Take advantage of Early Bird pricing and register now. The cost of $100 per person includes two days of quality programming, meals throughout the event, and opportunities to network with organic farmers in the region as well as speakers and trade show vendors.

This event is brought to you by Ohio State University Extension and Ohio State’s Organic Food & Farming Education and Research (OFFER) program. Continuing education credits will be available for Certified Crop Advisors (CCAs). For more information, visit go.osu.edu/organicgrains.