Weeds | University of Maryland Extension

Updated: May 29, 2024

Vegetable and Fruit News-2024 (Volume 15, Issue 3)

Vegetable and Fruit Newsletter, Volume 15: Issue 3, May 2024. Topics include: Preemergence Herbicides for Common Weeds in Vegetables, Greasiness in Apples: Why it Happens and How to Prevent it, Insect Scouting Tips, Beginning Farmer FAQ –Soil Testing, Upcoming UME and UMES Events

Updated: February 12, 2024

A Guide for Identifying Pigweed Species Commonly Found in Maryland (EB-2023-0654)

This hand-held guide provides information on how to identify and differentiate common pigweed species in Maryland including: Palmer amaranth, Spiny amaranth, waterhemp, and redroot/smooth pigweed. Authors: Kurt Vollmer and Ben Beale; Title: A Guide for Identifying Pigweed Species Commonly Found in Maryland (EB-2023-0654)

Updated: February 2, 2024

Vegetable and Fruit News-October 2022

Vegetable and Fruit News, Volume 13, Issue 7 (October 2022). Topics in this issue are Sensor Placement and Row Cover Impact on Fruit Rotting Diseases, Common Weed Survey, Testing for Soluble Salt in High Tunnels, Changes to the Whole-Farm Revenue Protection and Micro Farm Insurance Workshop, SARE Grant information, Apple Workshop, and Upcoming UME & UMES events

Updated: October 19, 2023

Evaluating Biosolarization as a Weed Management Tactic in Organic Vegetables

Biosolarization, akin to solarization, is a soil disinfection technique but involves the addition of organic amendments before the passive solar heating process. As the damp soil warms, organic materials break down, releasing allelochemicals and other biotoxic compounds briefly into the soil. Read more about "Evaluating Biosolarization as a Weed management Tactic in Organic Vegetables."

Updated: October 19, 2023

Using Spring-Seeded Cover Crops to Complement Weed Management in Cucurbits

Weed management in plasticulture vegetable systems can be challenging. Control can be achieved with herbicides, but fewer options are available due to lack of registered products and loss of efficacy due to the presence of herbicide resistance weeds. Cover crops are an alternative tool that has successfully been used for weed management in multiple cropping systems. Read more about "Using Spring-Seeded Cover Crops to Complement Weed Management in Cucurbits."

Tractor spraying on field with cover crops

Updated: October 4, 2023

Keys to Identifying Palmer Amaranth and Waterhemp (FS-2023-0653)

Pigweeds are annual weeds that can cause significant problems for Maryland farmers. Palmer amaranth and waterhemp are two pigweeds that are especially troublesome, and have been designated as noxious weeds by the Maryland Department of Agriculture. Therefore, it is required that these two species be actively managed to prevent their spread and resulting negative impacts on Maryland agriculture. To the untrained eye, Palmer amaranth and waterhemp can appear similar to each other and to other pigweed species. However they can be easily distinguished from one another by looking at some key botanical characteristics. Becoming familiar with these species allows for earlier detection, and as a result, improved management practices. Authors: Kurt Vollmer, Ph.D., and Ben Beale; Title: Keys to Identifying Palmer Amaranth and Waterhemp (FS-2023-0653)

Updated: May 30, 2023

Know Your Foxtails (FS-2023-0658)

Yellow, green, and giant foxtail are the three most common weedy foxtail species in Maryland. Knowing the differences between foxtail species and look-alike grassy weeds can assist with identification, and the selection of effective weed management strategies. Title: Know Your Foxtails (FS-2023-0658); Authors: Dwayne D. Joseph, and Leo Kerner

Updated: January 19, 2023

Branching Out - Fall 2022

Read about a bunch of stuff I ain't writ yet. There's also the News and Notes summary about stories you might have missed, as well as our regular features the Woodland Wildlife Spotlight, Invasives in Your Woodland, and the Brain Tickler challenge.

Male adult downy woodpecker. Photo © Evan Lipton| Macaulay Library

Updated: September 26, 2022

Thoughts on the Control of Palmer Amaranth in Organic Systems

An article on the control of Palmer amaranth in organic systems that will discuss the biology, Palmer amaranth weaknesses, management considerations, early detection, and elimination, managing populations in organic systems, considering cultural techniques/growing practices that are less conducive to palmer amaranth, strategic tillage, cultivation, and crop rotation/fallowing.

Updated: September 26, 2022

Minimizing Combine Weed-Seed Movement

Harvest is fast approaching for grain producers; some of which have already begun shelling corn in recent days. Though this time of year often marks the end of the season, some decisions we make at harvest have lasting effects on subsequent growing seasons; one of which is weed control. If weeds are allowed to mature and set-seed, harvest equipment can be highly effective at retaining, and transporting weed seeds from field to field, as well as dispersing weed seeds across the field, further increasing the weed seed bank.