Rutherglen bugs

Agronomist, Allan Edis (Landmark), has reported Rutherglen bugs causing feeding damage to an emerging canola crop, just west of Temora, in the South West Slopes region of New South Wales. Allan says the majority of Rutherglen bugs are nymphs, and appear to have moved into the crop from a neighbouring pasture paddock. In the most heavily infested areas, 3-5 bugs could be found per seedling plant. The majority of damage is concentrated along one edge of the paddock. Allan says typical sucking damage is evident, which appears as ‘small pin prick’ marks on the leaf surface, and the cupping of cotyledons and young leaves. Chemical control is deemed necessary.

The Rutherglen bug (Nysius vinitor) is a common native insect that attacks a wide range of crops and weeds including canola, lucerne, wheat, sunflowers, safflowers, linseed and sorghum. Adults are 4 mm long and grey-brown in colour with clear wings folded flat on their back. They are narrow-bodied with prominent dark eyes, and they are highly mobile. Nymphs are wingless and have a dark red, pear-shaped body. Rutherglen bugs are typically a problem in spring, but can also be a sporadic pest of seedling crops in autumn and early winter. During this time they can cause retardation of emerging seedlings and seedling death.

Rutherglen bugs are often found in paddocks that have had summer weeds especially an abundance of goosefoot, fleabane and wireweed. Swarms of the bugs often move out from under weed plants when they are disturbed. In winter, activity of adults and late-stage nymphs is relatively low. Numbers will increase again in spring when breeding recommences. They are regarded as opportunistic and can reach plague proportions in some seasons.

There are several organophosphates and synthetic pyrethroids registered against Rutherglen bugs. Be aware that Rutherglen bugs can readily reinvade a sprayed area due to their migratory behaviour and insecticide applications will not guarantee a clean crop. Controlling weeds in and around paddocks will reduce populations. Ploughing a deep furrow around the crop edge will prevent wingless individuals migrating from paddock margins.