Australia
April 23, 2008
With no effective miticides or
Wheat Streak Mosaic Virus (WSMV) resistant wheat varieties
available, hygiene measures, such as controlling volunteer
cereals or grasses during summer and completely removing them
two weeks before sowing, is recommended.
Less than 0.2 millimetres long, Aceria tosichella, or
Wheat Curl Mite, transmits Wheat Streak Mosaic Virus.
It is active after surviving summer on host plants if there is
sufficient autumn rain to establish a 'green bridge' of grasses
and volunteer cereals, enabling transfer of WSMV to adjacent
crops.
The mite can't live long without suitable green plant material,
so regions with 100 mm or more rainfall in January to March are
at the greatest risk of an outbreak.
GRDC supported DAFWA entomologist, Geoff Strickland said it
typically colonises the youngest tissue of wheat plants, causing
longitudinal rolling of leaves with high mite populations.
WSMV symptoms include light green-yellow, discontinuous streaks
and dashes parallel to veins.
"Unfortunately, symptoms are easily confused with nutritional
disorders, environmental effects and chemical damage," he said.
For more information, visit the
GRDC supported website
www.wheatcurlmite.org
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