Pest of the month: Broad mite

Month: December 2017

Pest: Broad mite – Polyphagotarsonemus latus

Broad mites causing deformed growth on Asian bell (Radermachera sinica)

Importance: Common and major nursery pest

Description: Egg: Transparent, less than 0.1 mm long, oval-shaped, surface characteristically covered in white bumps (stipules). Found mostly near veins and in depressions in leaves. Immatures: Whitish in colour with a distinct white stripe along the dorsal surface.Adult: Very small, barely visible to naked eye. Oval-shaped, mostly translucent but with a yellow-green tinge. Males are slimmer and are often carried by the female with the rear legs.

Damage: Adults are found mostly on underside of young apical leaves and in flowers.  Leaves become bronzed, russetted and distorted with down-curling margins, stems can be flattened. Fruit may be misshapen and russetted. Severely attacked plants are stunted and often die. By the time injury is first noticed the mites may no longer be on the damaged foliage. Symptoms may be mistaken for virus or herbicide damage.

For further industry pest information refer to the mite pest management plan and at www.pestid.com.au  An initiative of the Nursery Levy funded National Nursery Industry Biosecurity Program (NY15004) and Building the resilience and on-farm biosecurity capacity of the Australian production nursery industry (NY15002) project.