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Bermudagrass Mite1
D. E. Short and E. A. Buss2The bermudagrass mite (Eriophyes cynodoniensis) can be a serious pest wherever bermudagrass is grown in Florida. It does not attack other turfgrasses. It is an eriophyid or gall mite, which infests the southern United States. The most severe damage occurs to the coarser varieties of bermudagrass - Common, Ormond, and St. Lucie. Damage is usually not as evident on varieties such as Tiflawn, Tifdwarf, and Tifgreen.
Identification and Biology
The mites are extremely small, yellowish-white, somewhat worm-like in shape, and have two pairs of legs. A 20X hand lens or microscope is needed to find them - they cannot be seen with the naked eye. The mites are active primarily during late spring and summer, but may be active most of the year in southern Florida. They need 5-10 days to complete their cycle from egg to adult, so there are multiple generations each year. The mites tend to develop between the grass stem and blade sheath, which physically protects them from pesticide contact. They remain for most of their life beneath the grass sheath, and large numbers in all stages of development may be found under infested sheaths. Nearly 100-200 mites (eggs, immatures, and adults) can occur under one leaf. They cannot survive on bermudagrass seeds.Monitoring and Damage
Characteristic damage symptoms (Figure 1 ) are often enough to diagnose an infestation. The grass blades turn light green or yellow and curl abnormally. The internodes (the area between the joints of a stem) shorten, the tissues swell, and the grass becomes tufted so that small clumps are noticeable. This produces small "cabbage heads" or "witches brooms" in the grass. With heavily-infested grass, the clumps can be felt by moving a hand through the grass. The grass loses its vigor, thins out, and may die. Then, weeds may invade those areas. The presence of 4-8 stunted trufts per square foot may warrant a treatment.
CREDITS: University of Florida
Figure 1. Characteristic damage symptoms of bermudagrass mite. Biological Control
No information exists on the presence or effectiveness of natural enemies of the bermudagrass mite in the U.S.Cultural Control
Severe damage is associated with dry weather, insufficient irrigation, and low fertility. Mites can be spread on grass clippings, and could even disperse via insects or on the wind.To manage small infestations, scalp or closely mow the grass to a height of 3/4 inch and dispose of all clippings. To minimize plant stress after mowing, water the turfgrass thoroughly for three days. Mite infestations often occur on sloped ground where water drainage occurs, as well as near fence posts and other obstructions where mowing is minimal or where grass clippings are discarded. Keeping the turfgrass healthy and growing vigorously will help the plants tolerate or outgrow an infestation.
Chemical Control
Diazinon was effective in the past, but is no longer available for turfgrass use. Talstar, DeltaGard GC Granular*, DeltaGard T&O Granular, Dicofol 4E Miticide*, Dursban Pro*, or Kelthane 50 WSP (Danger signal word) are currently labeled against mites on turfgrass. Reapplication in 7-10 days may be needed to kill any recently-hatched immatures.* Not for use on residential home lawns.
Footnotes
1. This document is ENY-328, one of a series of the Department of Entomology and Nematology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First Published: October 1993. Revised: June 2005. Please visit the EDIS Web site at http://edis.ifas.ufl.edu.2. D. E. Short, retired professor-extension entomologist and E. A. Buss, assistant professor, Department of Entomology and Nematology, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.
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U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean.
Copyright Information
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