Weeds grow on every acre used for crop and timber production. Weeds also grow in those areas not used for crop and timber production. Weeds can be found just about everywhere and all times of the year.
Weeds in lawns: Weeds occur in home lawns during winter, spring, summer, and fall. There are many different types of weeds that invade lawns. A thick, dense turfgrass canopy is the best defense one can have against weed invasions. Diseases, insects, cold damage, inadequate sunlight, acid soils, poor drainage, fertilizer burn, poor fertility, poorly adapted turf type, poor mowing practices, or other factors can cause the turfgrass canopy to thin, creating areas for weeds to emerge. Follow recommended turf maintenance practices to provide the first level of defense against weed invasions. Herbicides can then be used to control those weeds that emerge in those areas.
Weeds in Forages: More than 4 million acres of native and improved grasses are grown for pasture and forages, in Mississippi. Weeds occur on most of the 4 million acres. Attitudes toward control differ as much as the people that manage the forages. Cattle producers tend to be more willing to control weeds when cattle prices are up than when cattle prices are depressed. Those growing hybrid bermudagrass hay for horses strive toward eradicating all weeds. In any event, when dollars are spent for lime and fertilizer, weeds should be managed to minimize competition between the forages and weeds.Good management practices such as selecting a forage that is suited to your area, maintaining soil pH in the range best suited for your type forage and applying fertilizer at recommended rates should be the first weed management practices used. Timely mowing and managed grazing pressure can also be utilized to help minimize weed growth and seed production.
Weeds in Corn: Corn acreage has increased substantially in Mississippi over the last few years. For many Mississippi farmers, corn is a new crop. As a result of this crop shift, many farmers are faced with many of the same problem weeds, but must control them in an unfamiliar crop. Since much of the corn in Mississippi is grown close to cotton, and often the same equipment is used to spray both cotton and corn, many farmers are skeptical of using herbicides such as 2,4-D which can injure cotton. Fortunately, many weeds can be controlled with other herbicides early in the season. As fall approaches and corn begins to mature and dry for harvest, morningglories and other weeds take advantage of the available sunlight and resume growth at full speed.The 10 most common weeds in corn, in Mississippi are broadleaf signalgrass, annual morningglories, southern crabgrass, common cocklebur, johnsongrass, sicklepod, purple nutsedge, pigweeds, Pennsylvania smartweed, and goosegrass. The 10 most troublesome weeds are broadleaf signalgrass, annual morningglories, common cocklebur, common bermudagrass, horsenettle, purple nutsedge, sicklepod, Palmeramaranth, southern crabgrass, and yellow nutsedge.
Weeds in Cotton: Weeds occur in all cotton fields, in Mississippi. Weed control in conventional tilled cotton combines many management tactics, including preplant tillage, preplant herbicides, preemergence herbicides, cultivation, and postemergence herbicides.Some farmers have taken a new look at an old weed management technique that was widely used in the 1950's and 1960's, flame cultivation.
Weeds in Soybeans: Soybean is the largest acreage row crop grown in Mississippi. Weeds are a significant pest problem in most soybean fields. Producers typically rely on preplant, preemergence and postemergence herbicide applications, often combined with cultivation to manage weeds. There are numerous herbicides available to control weeds in soybean.The 10 most common weeds in soybeans in Mississippi are johnsongrass, prickly sida, entireleaf morningglory, common cocklebur, pitted morningglory, spotted spurge, sicklepod, hemp sesbania, barnyardgrass, trumpetcreeper.The 10 most troublesome weeds in soybean in Mississippi are sicklepod, eclipta, redvine, spotted spurge, johnsongrass, prickly sida, horsenettle, Pennsylvania smartweed, common bermudagrass, and trumpetcreeper.One of the newest methods of weed management, in soybeans, involves transgenic cultivars that can tolerate nonselective herbicides, such as Roundup Ultra and Liberty. These cultivars are genetically modified to tolerate herbicides that will kill conventional soybean cultivars. The traditional approach to herbicide development was to synthesize a new herbicide, then simultaneously evaluate soybean tolerance and activity on several key weeds. Genetic engineering allows the company to develop crop tolerance to a herbicide that has already been examined by EPA and determined safe to use, and that provides good control of many weeds in soybean.
Weeds in gardens: Home gardeners face a variety of weeds each season. Weeds can easily be controlled by tillage prior to planting. The equipment used for tillage depends on the size of the garden and seriousness of the gardener. In a small garden, a shovel may be sufficient for preplant (or pretransplant) tillage, while larger gardens may require a tiller or tractor and assorted implements. Some gardeners may choose to use a herbicide, such as Roundup, that is labeled to kill existing vegetation before tilling the garden.Many gardeners use some physical weed control, such as cultivating, hoeing, or hand pulling to control weeds during the season. Plastic, either black or white, can be used to help minimize weed growth, but will not retard a troublesome weed like nutsedge. In addition to suppressing weeds, plastic helps heat the soil enabling producers to plant warm season crops earlier. One disadvantage to using plastic, however, is disposing of the used material at the end of the season .Another procedure that was practiced in agronomic crops in the 1940's and 1950's is cross cultivating. Cross cultivating is cultivating in perpendicular directions in the field. Plants in adjacent rows must be in perfect line with sufficient spacing for cultivating down the row and 90 degrees to the row. This is an effective method of removing weeds that emerge between plants. There are several herbicides that can be used in the home garden, although there are few herbicides that can be used on all types of vegetables in a garden. For example, a herbicide that is labeled and safe to use on corn may not be labeled or safe to use on tomatoes.
Herbicide label: Herbicides, like all other pesticides, are regulated by the Environmental Protection Agency and the Mississippi Bureau of Plant Industry within the Department of Agriculture .Attached to every pesticide container is a label that provides certain information. The label indicates the active ingredient and concentration, manufacturer, application rates to control certain pests, crops or areas that can be treated, precautions that must be followed to ensure the harvested commodity is safe (contains no illegal residues), clothing that must be worn during applications to prevent exposure, conditions under which the pesticide will not perform as expected, and other pertinent information.More information is available for weeds in vegetable gardens in the Home Gardening/Vegetables area of this Web site.
Frequently Asked Questions
Other Weed Information
Weed pictures and other information:
Exotic, invasive weeds:
US government agencies: