Various species

Other common names:

Eriophyoid Couch Mites (Aceria cynodoniensis), False Spider Mites (Dolichotetranychus australianus), Tarsonemid Kikuyu Mites (Steneotarsonemus hippodromus), Grass Webbing Mites (Oligonychus araneum and Oligonychus digitatus) and Zoysiagrass mite (Aceria zoysiae).  

Description:

• Mites are not insects; they are arachnids as are spiders and ticks.
• Mites rate second to insects in diversity and species number.
• Mites vary in length from <0.2mm to 5mm. Most can only be seen when magnified.
• Mite life cycles are very short – some mature in only a few days. They lay massive numbers of eggs.
• Mites do not have wings, so spread by other means.
• Source: Horticulture Australia (2012).

Susceptible Turf:

Green couch and hybrid green couch or hybrid bermudagrass, kikuyu, Zoysia matrella, Zoysia japonica and Zoysia pacifica varieties.

Symptoms:

• Distortion of terminal growing points is generally a clear sign of mite damage, but can also be confused with herbicide damage.
• As an infestation increases over time, the terminal shoots may turn black and die completely.
• Runners become short and distorted.
• Root development is impeded and runners “porpoise” without rooting down.
• Turf which typically runs and knits becomes open and clumpy with shortened runners.
• Affected turf is more easily moisture stressed.
• Turf which fails to knit produces a high percentage of broken rolls (often greater than 30%) in turf production.
• On sports surfaces the surface quality declines.
• Source: Horticulture Australia (2012). Refer to image below.

Control options:

• Industry thresholds are set a 4 - 8 stunted tufts (witches brooms) per 100 cm² (as noted by Bayer Turf and Ornamental).
• Pesticides: See available tabs below for registered products. It is important to break the lifecycle of the mite when using pesticides. Use as per label instructions to do so and change pesticide products containing a different active constituents if being used across another season or year. Mites build up resistance and pesticide control may be significantly diminished if directions and product change up is not undertaken.
• Integrated Pest Management (IPM): Use a combination of approaches listed on this page.
• Cultural: Nil.
• Mechanical: Nil.

References:

• Baker, W. E., T. Kono, and N. R. O'Neill. 1986. "Eriophyes zoysiae (Acari: Eriophyidae), a new species of eriophyid mite on zoysiagrass." International Journal of Acarology. 12: 3–6.
• Beehag, G. W. 1992. "Couchgrass culture in Australia." Turf Notes. 11: 10–11.
• McMaugh, P., Loch, D.S., and Knihinicki, D.K. (2011). TU10002: Mite damage: A survey of four warm‐season turf grasses. Final Project Report (Sydney, Australia: Horticulture Australia Ltd.), pp.77.
• McMaugh, P., and Loch, D.S. (2012). TU10004: Screening chemicals for control of eriophyid mites in four warm-season turf grasses. Final Project Report (Sydney, Australia: Horticulture Australia Ltd.), pp.25.

Disclaimer:

Turf Finder or its developer accepts with no responsibility for any consequences whatsoever resulting from the use of any information or product(s) listed herein. Products are to be applied as per label instructions.