Bermudagrass Mite

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Witchesbrooming caused by bermudagrass mites
Close up of witchesbrooming
Microscopic view of bermudagrass mites at leaf bases
  • Scientific Name: Eriophyes cynodoniensis Sayed [Phylum Arthropoda: Class Arachnida: Order Acarina: Family Eriophyidae]


  • Common Names: used to be called the bermudagrass stunt mite, but just bermudagrass mite is now the accepted common name.



  • Geographic Distribution: worldwide, wherever Cynodon is grown. Known distribution includes North and South America, Africa, Middle Eastern Countries, Asia and Orient, Australia and New Zealand. In the United States, this mite is found in states where above ground stems of bermudagrass remain green during the winter months.


  • Damaging Stage: larvae, nymphs and adults



  • Symptoms: Classic symptoms include “witchesbrooming” whereby leaves and buds at the nodes become bushy, forming a rosette or tuft. Early damage may be noticed when bermudagrass does not have vigorous growth in the spring and is often yellowed. The turf appears stunted and close inspection reveals that the stem length between nodes is greatly reduced. Heavy infestations produce an open, “tufted” appearance with irregular sections eventually turning brown and dying. Damage is most severe during periods of hot dry weather.


  • Description of Stages: This mite has stages typical of the eriophyid mite group. These are extremely small mites with worm-like soft bodies and only two pairs of legs facing forward.

Eggs: Round, translucent white eggs are about 1/3 the length of the adult.

Nymphs: The first nymph has the tapered worm-like shape of the adult but is almost clear. These mites have only two pairs of short legs rather than the four pairs of legs found on most mites. The abdomen has minute rings which look like segments. The second nymph is about 2/3 the length of the adult and more white in color.

Adults: Only females are known, as in most eriophyids. These look like the nymphs and are only 1/128 inch (0.2 mm) long when fully grown but have a whitish cream color.


  • Life Cycle and Habits:

Because of their small size, these mites are very difficult to study, and little is understood about their life cycles and habits. Most eriophyids lay less than a dozen eggs during their adult span and these usually hatch in two to three days. At 75 °F it is estimated that adulthood is reached in seven to ten days and eggs are laid for two to five days. Thus, a cycle can be completed in 10 to 14 days. This short time period allows for a rapid build up of a population during summer temperatures. The bermudagrass mite seems to be quite tolerant of high temperatures, having moderate mortality at 120 °F. Cold temperatures tend to stop development though survival during the winter can take place where bermudagrass remains green at the soil surface. This mite can apparently spread by the wind or by being carried on the bodies of insects, but the most common method of spreading is by transportation with infested turf. The mites cannot survive on bermudagrass seed.


  • Control Approaches: Eriophyid mites usually are not alwasy killed by normal miticides but may be killed by many insecticides. With the use of fine textured bermudagrasses on golf courses, this mite seems less abundant.

Cultural Control - Use Resistant Varieties - Common bermudagrass is often attacked but improved, fine textured varieties such as Tifgreen (238) and Tifway (419) have shown considerable resistance.

Cultural Control - Turf Maintenance - The bermudagrass mite does not do well in short cut turf. This is why the pest is rare on green or tee surfaces. In other areas, however, mowing too short may scalp the turf. Good fertilization and water will help reduce stress and mask mite populations. Mite attacks are seldom damaging during wet periods when bermudagrass is rapidly growing.

Chemical Control - Soft Pesticides - Though not specifically registered for this pest, some of the insecticidal soaps can be used on turf. Industry reports indicate that these soaps, when used with sufficient water to thoroughly wet the turf grass blades and stems, are effective in reducing the impact of turf-infesting mites.

Chemical Control - Traditional Pesticides - Proper identification is needed because water stress and disease can look like early mite damage. A microscope with at least 30 power magnification will be needed to adequately see the mites. Short residual pesticides may have to be reapplied in seven to 10 days to kill mites hatching from eggs. If bermudagrass mites are confirmed, there are very few insecticides/miticides that are capable of controlling eriophyid mites. Since these mites are well protected within the folds of plant tissues, regular applications may be needed to achieve acceptable control.

Monitoring

A three by four foot plastic rectangle should be strung on one ft2 grids (12 ft2 total). The sampling hoop consists of four sections of 1-inch PVC pipe. Two are three foot long segments and two are four foot long segments. The segments are joined with right angle connecters and glued. Holes are drilled through the sides at one, two and three (on the four foot segments only) feet from each corner. A monofilament string is then threaded, in a grid pattern, through the holes. This hoop is tossed onto the turf and ten of the ft2 grids are rated for mite activity. Each tuft of turf with a witchesbroom is counted. Fairways and roughs should be sampled every 50 yards and four hoop samples should be taken for each green apron. Tee banks should have two hoop samples. When presence of the mite activity is noted, samples should be taken every month. If the activity is increasing and exceeds four to eight tufts per ft2, chemical controls are probably warranted. Below four tufts per ft2, cultural controls should be used.