By: Harold Watters, CCA, Ohio State University Extension
So this year I am getting even more calls and comments on run away marestail.
“Last year I killed it, this year not so much” is often the remark I hear. And following is my response regarding Horseweed (Conyza canadensis), or Marestail as it is known in Ohio. This may be a new weed to you but the western side of the Ohio and particularly the southwest corner have been fighting it since about 2002. It takes a comprehensive effort, but it can be well managed. Continue reading
By: Mark Loux, OSU Extension
If you have never applied herbicide in fall to burn down winter annuals, or done it only infrequently, this might be the year to make an investment in fall herbicides. Fall treatments are an integral component of marestail management programs. They also prevent problems with dense mats of winter annuals in the spring, which can prevent soil from drying out and warming up, interfere with tillage and planting, and harbor insects and soybean cyst nematode. Continue reading
By: Mark Loux, OSU Extension
The world of soybean herbicide resistance traits has gotten more complex over the past several years. The good news is that we have new options for control of herbicide-resistant weeds, although it can be a little difficult to sort out which one is best for a given situation and whether the possible downsides of certain traits are tolerable. The following is a quick rundown of what’s available and some things to consider when selecting seed. Continue reading
The calendar says it is August but it sure doesn’t feel like it to me. As you drive further north on Route 23 and up onto I-75 crop conditions would lead one to think we were just starting July in many instances. However, the reality of everything is that the county fair begins in one week and Farm Science Review will be soon to follow. Speaking of FSR, we have pre-sale tickets available here in the office for $7 up until the week before the event. Continue reading
By: Mark Loux, OSU Extension
If you don’t already have to deal with waterhemp or Palmer amaranth, you don’t want it. Ask anyone who does. Neither one of these weeds is easy to manage, and both can cause substantial increases in the cost of herbicide programs, which have to be constantly changed to account for the multiple resistance that will develop over time (not “can”, “will”). The trend across the country is for Palmer and waterhemp to develop resistance to any new herbicide sites of action that are used in POST treatments within about three cycles of use. Preventing new infestations of these weeds should be of high priority for Ohio growers. Continue reading
By: Joe Boggs, OSU Extension
The dichotomous nature of cressleaf groundsel (a.k.a. butterweed) (Packera glabella; syn. Senecio glabellus) tests the tolerance of lovers of native wildflowers. On one hand, a sea of golden-yellow flowers carpeting farm fields in Ohio provides welcome relief from highway monotony. On the other hand, upright 2 – 3′ tall plants dominating Ohio landscapes presents a weed management challenge.
Cressleaf groundsel is so-named because its lower leaves resemble watercress. Its alternate common name of butterweed comes from its conspicuous buttery yellow flowers. Continue reading
By: Mark Loux, OSU Extension Weeds Specialist
Managing cover crops in a year like this can challenge even those with the most experience. A few suggestions regarding termination of covers:
• Increase glyphosate rates to compensate for larger size, and consider applying alone or just with Sharpen. Mixing glyphosate with other herbicides or ATS can reduce its activity on grass covers, especially when large. Herbicides that can antagonize glyphosate include 2,4-D, metribuzin, atrazine, and flumioxazin and sulfentrazone products. Sharpen has not caused a reduction in glyphosate activity on grass covers in university research. One approach would be to apply the glyphosate or glyphosate/Sharpen first, wait a few days, and then apply residual herbicides. Continue reading
By: Harold Watters, Ohio State University Extension Agronomic Systems Field Specialist
So I got some calls after our Extension Fall Weed Survey — if these are the problem weeds, then how do you deal with them?
It is becoming apparent that with the move to herbicide tolerant crops, we aren’t necessarily getting rid of all of our weeds — only 30% of our fields are weed free. Giant ragweed moved back into first place for worst weed, seen in 34% of fields overtaking marestail seen in 30% of fields. And then there is the pigweed problem — waterhemp appeared frequently, so did redroot pigweed and then there are the concerns about Palmer amaranth and its escape across Ohio.
||2018 Ohio rank
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By: Bob Hartzler, Professor of Agronomy at Iowa State University
I feel obligated to write something about EPA’s dicamba announcement, but will confess at this time I still have several questions that I’m seeking answers for. But here are my initial thoughts regarding the new approach to dicamba management.
- 45 days after planting.I’m not sure if this restriction replaces the previous restriction that limited applications up to and including the R1 soybean stage. Regardless, I see very little value to this new restriction. According to USDA-NASS Crop Progress reports, the 5-year average for Iowa soybean planting is 51% planted on May 20. Thus, applications would be allowed into July for much of Iowa’s soybean acres. In 2017, 90% of dicamba misuse complaints to IDALS were associated with applications made after June 15. I believe a date restriction would be more appropriate, a date in mid-June would be my preference.
By: Mark Loux, Ohio State University Extension Weed Specialist, previously published in the C.O.R.N. newsletter
If you don’t already have to deal with waterhemp or Palmer amaranth, you don’t want it. Ask anyone who does. Neither one of these weeds is easy to manage, and both can cause substantial increases in the cost of herbicide programs, which have to be constantly changed to account for the multiple resistance that will develop over time (not “can,” “will”). Continue reading