Turfgrass Weeds, Diseases and Insects

Turfgrass Weeds

Weeds are described as plants growing where they are not wanted. They can disrupt the appearance of maintained turfgrass surfaces. In addition, they compete with desired turfgrasses for space, water, nutrients and light. Turf weeds may be grasses, grass-like plants (rushes and sedges), or broadleaf plants with annual, biennial and/or perennial life cycles.

Weeds are classified as summer annuals, winter annuals, biennials and perennials. Annuals complete their life cycles in one season by flowering, maturing seed and dying. Summer annuals germinate from late March through July, depending on the location. They flower in the summer and die in the fall. Winter annuals germinate in the fall and early winter and usually die with warm weather in the spring or summer; however, they may continue to grow into early summer in cool seasons. Biennial weeds have a two-year life cycle. They create vegetative structures (leaves, stems and roots) during the first year, and reproductive structures (flowers and seeds) the second. Perennials live more than two years and may produce seed each season.

Broadleaves Grasses Sedges
Stem Round or square Round Triangular
Leaf Round, heart, oval, or linear Linear Linear
Root Tap roots, bulbous roots, fibrous Fibrous Fibrous

Turfgrass Diseases

In total, there are over 100 diseases that affect turfgrasses, and each turfgrass disease has its own unique prescription that should be followed for its control. Accurate diagnosis of diseases is a critical first step in their management. There are only about 26 diseases that develop in turfgrasses year after year and learning how to diagnose and manage these most common diseases will prepare you to meet most problems that arise.

Submitting a Sample for Turfgrass Problem Diagnosis

Three factors are required for a disease to develop: a susceptible plant, a pathogen and an environment that is favorable for pathogen growth. Disease will not develop unless these factors are present for at least several consecutive days. Because turfgrasses are perennial, the host plant is always present. The pathogens are always present as well, lying dormant in the thatch and soil when they are not causing disease. Therefore, it is the environment that triggers disease development. Weather conditions, management practices and microclimate are the environmental variables that have the greatest impact on disease development.

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Turfgrass Insects

Several insects and mites feed on grass, but not all of them cause economic or aesthetic damage. Many are harmless, some are beneficial and some are pests. Only a few cause significant damage and need immediate control. Keep in mind that insects are only one of many potential causes for thin or brown grass. Only about 3% of all insects found in turfgrass are pests. Diseases, nematodes, drought and nutritional disorders can also be damaging. The presence of a few pest insects does not mean that you have a problem. Most turfgrass areas have a few insect pests, but the level of infestation is far below the density of pests needed to cause visible turf injury. Correct identification of the problem can save money and prevent unnecessary pesticide applications.

 

  • Leafhoppers (Draeculacephala minerva and Deltacephalus sonorus)