Rutherglen bugs

Consultant, Glen Smith (3D-Ag), has reported issues with Rutherglen bugs in emerging canola crops west of Wagga Wagga, in the South West Slopes district of New South Wales. Feeding by large numbers of Rutherglen bugs has retarded the growth of seedlings in at least two paddocks. Glen says the highest numbers of Rutherglen bugs were found under stubble. The majority of damage is patchy within the paddocks. Typical sucking damage is evident and has resulted in the yellowing and cupping of canola cotyledons.

In one paddock, it appears the Rutherglen bugs have moved in from neighbouring pasture paddocks that contained favourable hosts such as capeweed, wireweed and fleabane over summer. Both nymphs and adults have been observed feeding on the canola cotyledons. In the most heavily infested areas, more than 5 bugs could be found per seedling plant. Chemical control is required in these situations. 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.

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. In winter, activity of adults and late-stage nymphs is usually relatively low. It is expected that numbers will decline naturally in the next month due to the cold weather conditions. Numbers will increase again in spring when breeding recommences. Controlling weeds in and around paddocks will reduce Rutherglen bug populations. Ploughing a deep furrow around the crop edge will prevent nymphs migrating from paddock margins.

For further information on Rutherglen bugs, refer to PestFacts Issue No. 4.