New mite species found in hazelnut orchards
The hazelnut mite (Tetranycopsis horridus) has been recently detected in Victoria's north east and near Melbourne. This is the first time the pest has been detected in Australia.
Overseas the species has a broad geographic distribution that includes Europe (from Spain to western Russia), China, and the United States of America. Hazelnut mites have been reported as destructive to some economic crops.
The mites feed on hazelnut leaves causing discoloration. The main host is hazelnut, but it has been reported on other species including walnut, spruce, pine, and yarrow.
Additionally, Tetranychid mites (spider mites) include some important pests in agriculture and forestry and can be found feeding on many trees, including vines, hazelnut, vegetables and ornamental plants.
Growers should examine their nursery stock or groves for symptoms of white or yellowish feeding spots on the upper leaf surface and the leaf underside for black spider mites.
What does the hazelnut mite look like?
Tetranycopsis horridus - live adult mite
What damage does the mite do?
Tetranycopsis horridus causes conspicuous white or yellowish feeding spots throughout the forests of hazel.
The mites attack the hazelnut leaf, both young and mature varieties; and are found mostly on the under surface, along with its eggs and cast skins. The eggs tend to be red in colour. A few are often located on the developing nuts and the associated bracts.
Signs of damage on a hazelnut leaf
Healthy hazelnut leaf
Healthy hazelnut leaf - no signs of feeding spots
What does it affect?
Tetranycopsis horridus has been mainly reported feeding on hazelnuts; however, growers should be aware that reports of the mite have associated it with walnuts (Juglans sp.), beans, pine (Pinussp.), willow, oaks (Quercus sp.) and alder (Alnussp.). Some hazelnut varieties appear to be more susceptible than others.
Can I control the pest?
Currently there are no chemicals approved for use in Australia, but in Victoria off label use of some pesticides may be permitted in specific circumstances. For more information on the potential off label use of pesticides for the control of Tetranycopsis horridus contact the DEDJTR Customer Service Centre on 136 186
How can I help?
Before leaving a host tree location, check your clothing, machinery and tools for signs of the pest.
Report suspected detections
Report any suspected detections of Tetranycopsis horridus by phoning the Exotic Plant Pest Hotline on 1800 084 881 (toll-free); or emailing photos of the suspected pest, together with a contact phone number and the pest's location, to firstname.lastname@example.org