Integrated Weed Management

Lately, I have seen several fields with Palmer amaranth flowers (Figure 1). It is imperative that these plants be managed before harvest (Palmer amaranth is listed as a noxious weed in Maryland and Delaware). At this point, mowing or herbicides will not improve yield nor prevent Palmer from germinating next year. Plants need to be physically removed from fields. Palmer amaranth has both male and female flowers on separate plants (Figure 2), and focus should be placed on removing the seed-producing females first. A single female can produce approximately 600,000 seeds per plant, and these seeds can remain viable for six years. Palmer seed matures within 2 weeks of flowering and if left unchecked, a single plant can infest an entire field within a few years (Figure 3). 

As planting gets underway, it is important to stay on top of our most troublesome weeds. In particular, marestail/horseweed, common ragweed, and Palmer amaranth. Below are two new charts to help determine the type of products to be included in the tank mix to best manage these weeds in corn and soybean.

Japanese stiltgrass is an invasive grass that is typically seen in wooded areas. It likes shaded, wet areas and can easily take over the forest understory. Unfortunately, it can also creep into pastures and hay fields. The leaves of Japanese stiltgrass are wider and shorter than most of our common pasture grasses. There is also a distinctive silvery midvein that is slightly off-center from the middle of the leaf (Figure 1).

Agronomy News is a statewide newsletter for farmers, consultants, researchers, and educators interested in grain and row crop forage production systems. The topic for this edition is Cost-Share Grants Expanded, Evaluating Wheat Stands, Fusarium Head Blight Management, Early-Season Wheat Disease Scouting, April IPM Insect Scouting Tips, Cover Crop Termination for 2021, Maryland Circuit Court Judge Reverses Final Maryland AFO Permit, Maryland Ag Land Preservation, Pesticide Disposal Program, Pesticide Recertification Workbook, US Corn & Soybean Planting Acreage Report, Cooperators Needed For On-Farm Nitrogen Trials, What To Do With Thinning Alfalfa Stands, Weather Outlook, and Regional Crop Reports.

Agronomy News is a statewide newsletter for farmers, consultants, researchers, and educators interested in grain and row crop forage production systems. The topic for this edition is Preemergence Herbicides, Mowing Pastures: To Mow or Not to Mow, Checking Vegetative Growth Stages, Summer Nutrient Management Tips, Wheat Yields & Double-Crops—Time is Important to Maximize Yield, New Extension Agent, 2021-2022 Cover Crop Sign-Up, LEAD Maryland Fellowship Applications, MDA Pesticide Exams, MDA Pesticide Disposal Program, Weather Outlook, and Regional Crop Reports.

Agronomy News is a statewide newsletter for farmers, consultants, researchers, and educators interested in grain and row crop forage production systems. The topics for this edition are

Over the past few years there have been quite few cases in Maryland of injury to grapevines from herbicides that were sprayed to control weeds before planting crops on adjacent or nearby fields. Damage has ranged from some minimal leaf distortion through severe damage, crop loss, and vine death.

Greenhouse Herbicides for Vegetables