Native budworm update. Caterpillars are being found in cereals
Farmer Peter Cripps has been finding native budworm caterpillars in some pasture paddocks at Binnu, and also reports finding 10 budworm caterpillars per 10 sweeps in a wheat crop.
Nick McKenna (Planfarm) has found up to 35 budworm caterpillars per 10 sweeps in a wheat crop near Northampton and also reports finding budworm caterpillars in a nearby canola crop.
Research scientist Christiaan Valentine (DPIRD) reports finding 30 native budworm caterpillars per 10 sweeps in a wheat crop west of Morawa. In a nearby wheat crop there were 1 per 10 sweeps. Christiaan suspects that higher budworm populations in the first crop originated from early budworm moth flights laying eggs on the volunteer lupins which were sprayed out, as the second crop with very few budworm was not in lupins last year.
Farmer Brent Payne has found 10-15 budworm grubs per 10 sweeps in a wheat crop west of Morawa that was in lupins last year. In nearby wheat on wheat paddocks he reports finding lower grub numbers with around 2-3 budworm grubs per 10 sweeps.
Wayne Birch (Nutrien Ag Solutions) reports finding 5-10 native budworm caterpillars per 10 sweeps in serradella pastures north of Moora. Also present in the serradella pasture were 5-10 weed web moth caterpillars per 10 sweeps.
A farmer south west of Dalwallinu reports finding native budworm caterpillars causing damage to a lupin crop.
Jessica Cole (DKT Rural Agencies) Reports finding one budworm caterpillar per 10 sweeps in a flowering lupin crop south of Kellerberrin.
Cara Allan (Syngenta) reports finding a few patches of native budworm caterpillars causing feeding damage to a canola crop north of Beverley.
Plant virologist Ben Congdon (DPIRD) reports that native budworm caterpillars are being found in vetch pastures at Condingup.
Why are native budworm in cereal crops again?
A similar scenario occurred last year where early and heavy native budworm moth flights occurred in the northern agricultural region and the moths laid eggs on any wild radish, volunteer canola or pulse plant that the moths could find before they were sprayed out. The remaining caterpillars had no choice but to then crawl onto the cereal plants and have a feed.
However, cereals are not a preferred host of native budworm and, as expected, native budworm numbers crashed in cereal crops which were investigated by DPIRD staff in 2019.
During the 2019 season caterpillar samples were collected at properties at Ballidu and Coorow, which had significantly high caterpillar numbers in wheat crops, because there was a chance they were another related species which does attack cereals. These species include the lesser budworm, Heliothis punctifera, or the corn earworm, Helicoverpa armigera. However, the caterpillars were identified as native budworm, Helicoverpa punctigera, using molecular barcode techniques.
High native budworm numbers are being trapped
Growers are urged to monitor their crops for chewing damage, especially pulses, canola and pasture legumes given the high numbers of budworm moths being detected in DPIRD’s moth trapping program in previous weeks.
Quite high numbers of native budworm moths continue to be reported from some areas of the wheat belt. The larger native budworm flights recorded by budworm trappers this week include; Merredin (422 moths over 14 days), Mukinbudin (137, 14 days), Beacon (88, 14 days), Dowerin (36 over 7 days).
A mapped view of the native budworm trap captures is available at cesar’s MothTrapVisWA page. See screenshot below showing native budworm trap data for 21 July to 29 July 2020.
Pesticide options for the control of native budworm and DBM can be found in DPIRD’s 2020 Winter Spring Insecticide Guide.
Detailed information on native budworm can be found at DPIRD’s Management and economic thresholds for native budworm page and 2020 PestFax Issue 7 article Native budworm and other moths are active.
For more information contact Alan Lord, Technical Officer, South Perth +61 (0)8 9368 3758 or +61 (0)409 689 468.
Article authors: Alan Lord (DPIRD South Perth) and Dusty Severtson (DPIRD Northam).