Rutherglen bugs

Agronomist, Kate McCormick (John Stuchbery and Associates), reports Rutherglen bugs (Nysius vinitor) have been observed in a canola crop near Murrayville, in the Mallee district of Victoria. Kate says the numbers are relatively low and not presently thought to be causing significant damage. Oilseeds Development Officer, Felicity Pritchard, has also recently observed Rutherglen bugs on a canola crop, near Horsham, in the Wimmera, Victoria.

The Rutherglen bug is a common native insect that attacks a wide range of weed and crop hosts, including sunflowers, linseed, canola, wheat, sorghum, safflower and lucerne. In some seasons Rutherglen bug can reach plague proportions, typically when the senescence of weed hosts in spring and early summer forces adults and nymphs into nearby crops.

Adult Rutherglen bugs are 4 mm long, have clear wings and are narrow bodied. They are grey-brown in colour, have two prominent black eyes and are very mobile. Immature Rutherglen bugs are dark red and more swollen in shape than adults.

Rutherglen bugs are sap suckers and damage to susceptible plants is similar to that caused by aphids. They do not usually damage standing crops of rapeseed but they can cause problems by contaminating grain at harvest. The presence of Rutherglen bugs may render the grain unacceptable because they contain tainting body oils. Growers have solved the problem of contamination by attaching screens to headers or by harvesting at night.

Canola should be checked during podding. Rutherglen bugs can be controlled by removing weeds they use as hosts and by ploughing a deep furrow around the crop, which prevents wingless individuals migrating from weeds. As Rutherglen bugs can readily reinvade a sprayed area, insecticide application will not guarantee a clean sample.