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Couch mites – a turf pest profile

Damage from Couch MiteCausal Agent
Aceria cynodontis (Eriophyes cynodoniensis)

Susceptible turfgrasses  
Common couch, the “Tif” hybrids more resistant

Symptoms
This pest is also in the USA and South Africa where it is referred to as Bermudagrass Mite. Typical symptoms could include:

      – The first indication is that turf is not growing as vigorously as it should in spring, despite adequate irrigation and fertility
      – Leaf tips firstly appear yellow and start rolling
      – Symptoms progress to shortened internodes with the development of  ‘witches broom’
      – Progresses further to affected turf areas, with a clumped appearance, resembling a miniature cabbage head
      – Leaves may die back to stems
      – If not controlled, stems and stolons may die back

Close up of couch miteConditions favouring couch mite
        –  Dry and warm weather during spring and summer
        – Turf under stress from irrigation, fertility and heat will recover slower from damage

Life cycle
         – Over winter in green leaf sheaths
         – Females start laying eggs in spring
         – Multiple life cycles per season of only 7-10 days depending on temperature
         – Can survive temperatures of up to 50ºC
         – Nymphs and adults will feed under leaf sheaths with mixed populations of up to 200 individuals per leaf sheath
         – All stage primarily spread by clippings

Cultural control
         – Maintain adequate fertility levels
         – Counter possible factors contributing to slow turf growth
         – Reduce mowing height and collect clippings in affected areas

Microscopic photograph of a couch mite (0.2mm)

Chemical control
General – pyrethroids, diazinon
Apply to wet turf or add surfactants to aide with penetration, re-apply 7-10 days later

What to look for
        – Warm and dry climate (20 – 40ºC)
        – Retarded turf growth
        – Yellowing ‘witches broom’ with tufty and uneven growth patches
        – Small wormlike mites (0.2 mm) under leaf sheaths of affected plants
        – Recent history of increased mowing height or no clipping removal

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