A fairly common question this time of year – where I have planted cover crops, do I still need a fall herbicide treatment to help manage marestail? The underlying premise here is that where a cover crop develops enough biomass to adequately cover the ground by late fall, it can contribute substantial suppression/control of marestail. Grass covers seem to be most effective at suppressing marestail, as long as they are planted early enough in fall to develop this type of biomass. Grass covers can also be treated postemergence in the fall with several broadleaf herbicides, while this is not possible in covers that contain broadleaf crops – legumes, radish, etc. There are no hard and fast rules with regard to this situation but here are some things to think about:

– Herbicide options for cereal rye and wheat covers generally include all of the typical postemergence herbicides that are labeled for fall use in small grains – 2,4-D, dicamba, 2,4-D/dicamba premix, Huskie, etc. We do not recommend use of 2,4-D in fall on small grains grown for yield because of the potential for crop injury and yield loss. However, we have applied 2,4-D to cereal rye and ryegrass in our research, and either injury did not occur or was minor enough that we did not detect it. Yield is a not a factor for cover crops anyway. Late-planted rye and wheat, which would be less developed at the time of application, may be more sensitive to 2,4-D injury.

– Do not apply dicamba or 2,4-D around the time of planting due to risk of injury. Delay applications until cover has at least a few inches of growth. It is possible to make a preemergence application of glyphosate plus Sharpen, and Sharpen alone could work if marestail is the only weed of concern.

• Decisions about whether to treat a cover yet this fall should probably be based on several factors and how they affect cover crop development and marestail control: date of cover planting – earlier is better; seeding rate – higher is better; row spacing – narrower is better; ground cover – more is better (or less bare ground observed is better); overall cover biomass – more is better. Some of these factors are related of course. A higher seeding rate may net be needed to obtain adequate ground cover when planting early, but it could help in later planting. Even where the cover is optimized, fall application may be the safe strategy in fields with a history of dense marestail infestations that always seem to be a problem to control.
• Spring burndown management can also have a role in the fall herbicide decision. In our research in soybeans, maximum suppression of marestail often occurred when the cover crop kill in spring was delayed until close to planting, compared with early April, where we had substantial fall biomass. At one site however, the rye did not provide near as much suppression, and marestail control was maximized by applying in April, when marestail were smaller and more sensitive to 2,4-D. So it’s possible to compensate for the lack of a fall herbicide treatment by applying the burndown earlier, or by applying a more aggressive burndown treatment. For example, using dicamba in the soybean spring burndown/residual treatment will often result in more effective control compared with 2,4-D. Preemergence yuse of dicamba in Xtend soybeans also allows application of the burndown anytime before crop emergence if that’s the way a grower wants to manage the rye. Bottom line – relying on 2,4-D still in the spring burndown might sway the decision toward still treating in fall, while relying on dicamba could sway the decision the other way, all other factors being equal.

In summary, factors allowing for greatest possibility of skipping application of fall herbicides to the cover crop: 1) earliest possible cover planting and development of substantial fall growth that prevents bare ground; 2) use of more effective spring burndown herbicides; and 3) fields with low marestail populations.

The number of acres planted to malting barley in Ohio this fall is at an all-time high and will likely continue to increase over the next few years. Although barley is not new to Ohio, raising it for malt is new to us and considerably different from raising it for feed or raising wheat for grain. In particular, the grain quality requirements for malting barley are different from the requirements for feed or grain, and as such there are a few differences in terms of how the crop is managed during the growing season. However, in spite of these differences, there are several key fall management guidelines for wheat and feed barley that would apply equally well to malting barley. For instance, variety selection, planting date, weed, disease, and pest control are just as important for malting barley as they are for wheat. See the links below from Ohio State and Cornell Universities for helpful tips on how to manage barley for malt in Ohio and the eastern US in general:

https://u.osu.edu/osuweeds/files/2017/10/barley-guide-2n9akle.pdf

https://fieldcrops.cals.cornell.edu/small-grains/malting-barley

According to the USDA/NASS (https://www.nass.usda.gov/) as of Sunday, Oct. 15, 21 percent of Ohio’s corn was harvested for grain, compared to 34 percent for last year and 32 percent for the five-year average. Wet weather delayed corn harvest across the state and is not helping with field drying. Some growers are delaying harvest until grain moisture drops further. However, these delays increase the likelihood that stalk rots present in many fields will lead to stalk lodging problems. Some serious stalk rot and lodging problems have already been reported, as shown in the image submitted by Curtis Young in Van Wert County. Leaving corn to dry in the field exposes a crop to unfavorable weather conditions, as well as wildlife damage. A crop with weak plant integrity is more vulnerable to yield losses from stalk lodging and ear drop when weathering conditions occur. Additional losses may occur when ear rots reduce grain quality and can lead to significant dockage when the grain is marketed. Some ear rots produce mycotoxins, which may cause major health problems if fed to livestock.

Several years ago we conducted a study that evaluated effects of four plant populations (24,000, 30,000, 36,000, and 42,000 plants/A) and three harvest dates (early-mid Oct., Nov. and Dec.) on the agronomic performance of four hybrids differing in maturity and stalk quality. The study was conducted at three locations in NW, NE, and SW Ohio over a three-year period for a total of eight experiments. Results of this study provide some insight on yield losses and changes in grain moisture and stalk quality associated with delaying harvest. The following lists some of the major findings from this research.

KEY FINDINGS

• Results showed that nearly 90% of the yield loss associated with delayed corn harvest occurred when delays extended beyond mid-November.
• Grain moisture decreased nearly 6% between harvest dates in Oct. and Nov. Delaying harvest after early to mid Nov. achieved almost no additional grain drying.
• Higher plant populations resulted in increased grain yields when harvest occurred in early to mid-October. Only when harvest was delayed until mid-November or later did yields decline at plant populations above 30,000/acre.
• Hybrids with lower stalk strength ratings exhibited greater stalk rot, lodging and yield loss when harvest was delayed. Early harvest of these hybrids eliminated this effect.
• The greatest increase in stalk rot incidence came between harvest dates in October and November. In contrast, stalk lodging increased most after early-mid November.
• Harvest delays had little or no effect on grain quality characteristics such as oil, protein, starch, and kernel breakage.

In this study, yields averaged across experiments, populations and hybrids, decreased about 13% between the Oct. and Dec. harvest dates. Most of the yield loss, about 11%, occurred after the early-mid Nov. harvest date. In three of the eight experiments, yield losses between Oct. and Dec. harvest dates ranged from 21 to 24%. In the other five experiments, yield losses ranged from 5 to 12%.

Grain moisture content showed a decrease from the Oct. to Nov. harvest dates but little or no change beyond the Nov. harvest dates. Grain moisture, averaged across experiments, hybrid, and plant population, decreased 6.3% points between the Oct. and Dec. harvest dates, with most of the decrease occurring between the Oct. and Nov. harvest dates (5.8 % points); only a 0.5 % point decrease occurred after early-mid Nov. Population effects on grain moisture content were not consistent. Differences in grain moisture were evident among hybrids on the first harvest date in early-mid Oct. but were generally negligible on the later dates.

A Field Loss Calculator for Field Drying Corn

Agronomists at the University of Wisconsin have developed a “Field Loss Calculator” Excel spreadsheet available at: http://corn.agronomy.wisc.edu/Season/DSS.aspx that allows producers to calculate the costs of harvesting today versus allowing the crop to stand in the field and harvesting later. The spreadsheet accounts for higher drying costs versus grain losses during field drying. It allows the user to account for elevator discounts and grain shrink.