Palmer amaranth (Amaranthus palmeri), a member of the "pigweed" family, is one of the most troublesome weeds in many southern row crops. Seed can germinate all season and plants can grow to over 6 feet in height. Plants have either male flowers that shed pollen or female flowers that can produce up to 600,000 seed per plant. One Palmer amaranth per 30 foot of row can reduce cotton yield by 6 to 12%.

Palmer amaranth (Amaranthus palmeri), a member of the "pigweed" family, is one of the most troublesome weeds in many southern row crops. Seed can germinate all season and plants can grow to over 6 feet in height. Plants have either male flowers that shed pollen or female flowers that can produce up to 600,000 seed per plant. One Palmer amaranth per 30 foot of row can reduce cotton yield by 6 to 12%.

The Virginia Pest Management Guide (PMG) series lists options for management of major pests: diseases, insects, nematodes, and weeds. These guides are produced by Virginia Cooperative Extension and each guide is revised annually. PMG recommendations are based on research conducted by the Research and Extension Division of Virginia Tech, in cooperation with other land-grant universities, the USDA, and the pest management industry.

Over past decades, there has been a steep emergence in the use of larger and heavier agricultural machinery including for tillage, planting, spraying, and harvesting. Although this is done to achieve higher productivity and efficiency, the unregulated traffic in the crop fields raise wheel loads to result in heavy soil compaction risks. Soil compaction is one of the major reasons for soil health degradation impacting physical, chemical, and biological properties of the soil and eventually the crop productivity. We present the impact of soil compaction on crop yield and assess Controlled traffic farming (CTF) as a possible solution. Study results show that the soil compaction was higher for the track zone compared to the no-track zone for both the corn and soybean growing fields. Importantly, this impact was prominent in the root zone depth i.e., till and beyond the hard pan. In some cases, the compaction varied so prominently that it led to the formation of two hard pans. Evaluations for the CTF also showed a trend that the field treatments with no cover crop experienced the highest soil compactions whereas the treatments with cover crop experienced the least compaction in most cases. It was also evident that soil compaction led to reduced crop health which likely also impacts the crop yield.

Hemp is a new crop to Virginia agriculture and available information about pest management and general crop production is lacking. This guide compiles the current known information about pest (insect and mite, disease and pathogen, and weed) management and crop production for hemp grown in Virginia. This is a first version and updates will occur in the future.

Herbicides that are usually associated with contamination of straw/hay, turf clippings, manure, and composts are growth regulator herbicides or synthetic auxins, a group of herbicides that mimics plant hormones and regulates growth. These herbicides are labeled for control of broadleaf weeds in grass crops, such as pastures and corn; in turfgrass, including lawns, golf courses, parks, and highway turf; and in noncrop areas. Vegetable and fruit crops, as well as broadleaf ornamentals can inadvertently be injured by these chemicals through drift of spray droplets, volatilization, and spray tank contamination or by residues in straw, manure, turf clippings, or compost. Diagnosing the specific herbicide responsible for the plant damage can be difficult. This publication focuses on damage caused by herbicide residues.

Combine harvesters can disperse weed seed, spreading them within a field and from field to field. Harvest Weed Seed Control (HWSC) is a method of weed control that concentrates, removes, or kills weed seeds that are retained on weed plants at the time of crop harvest. HWSC can be used to reduce the soil seedbank and thus future weed problems. It can also aid in herbicide resistance management, by killing or removing seeds produced by weeds that have escaped herbicidal control. This publication overviews current options to adopt HWSC and research results from Virginia.

DuraCor is a new herbicide currently registered for use in pastures and hayfields. ProClova is a new herbicide expected to be registered for use in January 2021. Both DuraCor and ProClova are used to control broadleaf weeds, however, a major benefit of ProClova (but not DuraCor) is the preservation of white clover. The objective of our research was to evaluate the efficacy ProClova on broadleaf weed species and safety on white clover.

This publication provides information on giant hogweed identification, including how to distinguish between look alike species, and what to do if you think you have found giant hogweed.

This publication reviews options for controlling common grassy weeds in grass forages including chemical and cultural management options. Specific weeds are discussed in detail including johnsongrass, Japanese stiltgrass, broomsedge, and foxtail species.

Italian ryegrass (Lolium perenne L. ssp. multiflorum) is the most common weed reported in wheat fields in Virginia. It is a winter annual weed and germinates when day/night temperatures range from 50/41°F to 77/41°F, which coincides with wheat germination. The emergence of this weed can occur both in fall as well as spring seasons. Controlling Italian ryegrass in wheat with herbicides becomes challenging as both are grass species, and limited herbicide options are available, especially when it is herbicide-resistant. In Virginia, Italian ryegrass populations are resistant to ALS-inhibitors (Group 2), and/or ACCase-inhibitors (Group 1) herbicides. Experiences from on-station and on-farm research indicate that postemergence herbicides alone cannot provide complete control of Italian ryegrass. A combination of preemergence and postemergence herbicides ensures effective control of this troublesome weed.

No-till seeding has become accepted practice for establishing forage grasses and legumes for a number of reasons. Foremost among these is that no-till management helps keep soils in place. Tilling soils to create a seedbed for new forage stands greatly increases the risk of soil erosion during the establishment period.