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Weed Control
Definition
Weeds are plants out of place. A plant may be desirable in one situation and a weed in another. For example, creeping bentgrass plants can invade a Kentucky bluegrass lawn and cause unsightly patches. On a golf green, however, creeping bentgrass is highly desirable as the predominant plant. Weeds detract from the beauty of lawns due to the contrast in color and texture between the desired grass plants and the weeds. In addition, weeds compete with the desired grass plants for available water and nutrients, and this usually results in the thinning of the desirable plant cover. Identification and Characteristics Lawn weeds may be divided into two classes based on the way in which they emerge from the seed. Monocots emerge with a single seed leaf, but dicots emerge with two seed leaves. Most monocot weeds found in turfgrass are from the family Gramineae and are called weedy grasses. They include crabgrass, annual bluegrass, tall fescue, and quackgrass. Dicots are called broadleaf weeds and include dandelion, clover, ground ivy, knotweed, and plantain. These two types of weeds are divided into groups according to the plants’ length of life. Perennial weeds have a life of more than two years, although new seeds may be produced every year. Biennial weeds have a life of two years. They generally store up food reserves in the leaves and roots the first year and produce seed in the second year. Control for perennials and biennials is similar, so they are often grouped together. Annual weeds germinate from seed, grow, flower, and produce seed in less than one year. Summer annuals germinate in the spring and mature in the fall. Winter annuals germinate in the fall or late winter and mature in late spring. Methods of Weed Control Effective control of weeds in turf is based on correct identification. Turf weeds can often be controlled by altering the cultural practices to favor the grass plants rather than the weeds. Cultural controls may include raising or lowering the mowing height, changing the frequency of mowing, lengthening or shortening the period between irrigations, increasing or decreasing the application of fertilizer, or aerifying the soil. A combination of proper cultural practices plus prudent use of chemical is sometimes necessary to control weeds effectively in turf. Whenever herbicides are used, container labels should ALWAYS be read and followed carefully. Pre-emergence herbicides affect germinating seeds. To be effective, the herbicide should be applied two to three weeks before weed seeds germinate, so pre-emergence herbicides are most effective against annual weeds. Post-emergence herbicides are used to kill weeds after the weed plants are up and growing. To be effective, most post-emergence herbicides must be absorbed through the leaves. Therefore, liquid sprays generally work better than dry, granular materials, but granular formulations may be the most practical way for homeowners to apply these materials. Post-emergence herbicides are most effective when applied when the weeds are young and growing vigorously. Safeguard Pest Control will identify your weeds and recommend a program that will be effective. |