Rutherglen bugs

Immature Rutherglen bugs (Nysius vinitor) have recently been identified for agronomist, Laura Watson (Landmark), from a wheat crop near Corowa, in the Riverina district of New South Wales. Laura reports finding very high numbers across a 180 ha paddock and says plants appeared to be unthrifty and showed some evidence of feeding damage. Although Rutherglen bugs are more likely to be a problem in spring, they can be sporadic pests at this time of year under favourable conditions.

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 bugs can reach plague proportions, typically when the senescence of weed hosts in spring and early summer forces adults and nymphs into nearby crops. Highest numbers of Rutherglen bugs are often observed along crop perimeters.

Adults 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, more swollen in shape than adults and lack fully-developed wings. Both adults and nymphs are sap-suckers and damage to susceptible plants is similar to that caused by aphids. Feeding by high numbers of bugs can cause cupping of leaves and retardation of emerging seedlings.

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. There are also several organophosphates and synthetic pyrethoids registered against Rutherglen bugs, although insecticide applications will not guarantee a clean crop as winged Rutherglen bugs can readily reinvade sprayed areas.

Click here for images of Rutherglen bugs.