Bermudagrass Mite

This eriophyid mite is host specific to bermudagrass, Cynodon spp. It is widely distributed in New Zealand and North Africa. Entomologists suspect that it originated in Australia. The first detection in the U.S. was in 1959 in a bermudagrass lawn in Phoenix, AZ. Now it is a major pest of bermudagrass in Arizona. In 1962, it was detected in Florida and is now found throughout the southern states.

The bermudagrass mite is a major problem on golf courses. It survives best on grass that is not mowed closely, such as the edge of bunkers, the lips of sand traps, and around trees. In home landscapes it is more of a problem on well fertilized lawns.

The first symptoms of a bermudagrass mite infestation is grass that fails to begin normal growth although it is well fertilized and properly watered. The mites feed under the leaf sheaths and suck sap from the stems. At first the leaf tips yellow slightly and the leaf tips begin to roll. As damage continues, the internode distance shortens and “witches broom” or rosetting occurs. As the damage continues to get worse, the grass develops clumps that resemble miniature cabbage heads. The leaves eventually die back to the stem. If not controlled, the stems and stolons may die. Mite injury is much more severe during hot, dry periods. The injury can initially be mistaken for water or nutrient stress. Careful examination of the grass with a 15X to 20X hand lens will reveal the mites. The leaf sheath should be pulled back to make detection easier.

Under summer conditions the mites can go from an egg to an egg-laying female in 7–10 days. This allows populations to build very quickly. All life stages are found together under the leaf sheaths. As many as 200 mites may exist under a single leaf sheath.

Mites are spread by way of clippings, by hitchhiking on insects in the grass, by the wind, and by water. It is a good practice to remove the clippings from an infested area. Proper water and fertility management will help infested grass recover and may prevent damage in the first place.

Chemical controls can be used, but the spray must penetrate the leaf sheath to contact the mites. Addition of a spray adjuvant to enhance penetration may help. A second application within a week is usually needed to kill the newly hatched mites.

A few of the improved cultivars of bermudagrass are resistant to bermudagrass mites. These include ‘FloraTex’, ‘Midiron’, and ‘Tifdwarf’. Most other common varieties and cultivars are susceptible.

Prepared by Clyde S. Gorsuch, Extension Entomologist/ Professor, Department of Entomology, Soils, and Plant Sciences, Clemson University.

EIIS/TO-19 (New 08/2003).

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