sustainability through science & innovation

Bug briefing | 14 July – 3 August

Bug Briefing is an overview of some recent invertebrate reports sent to PestFacts south-eastern, providing a snapshot of pest and beneficial activity in broadacre crops and pastures in Victoria and southern NSW.


Native armyworm larvae

Our general sense from reports is that armyworm, Mythimna convecta and Persectania spp., are present in many paddocks in cereal cropping regions, although there is variability in larvae sizes and population densities.

In the Murray region of NSW near Deniliquin, half a hectare of wheat was stripped down to bare stems by armyworms. The larvae were easily detected feeding on plants and sheltering under soil clods. In the worse affected parts, over 50 larvae/m2 were found.

Armyworm larva (most likely inland armyworm) were found lopping a few lentil branches in the Victorian Mallee. The damage was isolated. The armyworm species that occur in south-eastern winter cropping season prefer cereals and grasses. They aren’t expected to cause a lot of damage in lentils, although occasional branch lopping is not unheard of.

Armyworm damage in wheat. Images: Stuart McColl


Herringbone caterpillars

Herringbone caterpillars, Proteuxoa sp., were found in a wheat paddock near Manangatang in the Victorian Mallee. The larvae were found in the soil under plants that displayed chewing symptoms.

Herringbone caterpillars were also spotted in a barley paddock amongst stubble trash near Nhill in the Victorian Wimmera.

Brown pasture looper

Brown pasture looper, Ciampa arietaria, larvae continue to be spotted near Henty in the NSW Riverina. Large numbers of small to large larvae continue to be found chewing on lucerne, pastures, lupins and capeweed.

In the same region near Yerong Creek, a paddock of lupins had significant damage in patches where the larvae had stripped the leaves bare.

Pasture webworm

Pasture webworm, Hednota sp., larvae were found causing foliar chewing damage to a couple of cereal crops near Ganmain in the NSW Riverina. The larvae were found where there were some grasses present in early autumn prior to sowing. These larvae, which shelter during the day, were discovered once plants were pulled up and they were found amongst the roots.

Feeding damage by pasture webworm larvae. Images: Rohan Brill

 

Aphids

Russian wheat aphid, Diuraphis noxia, were spotted on isolated wheat plants west of Henty in the NSW Riverina. Similarly, low levels were reported in a wheat paddock near Gre Gre South in North Central Victoria.

Near Minyip in the Victorian Wimmera, a larger Russian wheat aphid population was reported in a wheat paddock, with one plant/m2 displaying symptoms.

Green peach aphid, Myzus persicae, was discovered causing significant direct feeding damage in a canola crop near Marnoo, North Central Victoria. Very high numbers were discovered under the leaves with low lying, frost affected area most impacted.

In the same region, cowpea aphid, Aphis craccivora, hot spots were found on faba beans, with frost affected plants also most impacted.

Large numbers of bluegreen aphid, Acrythosiphon kondoi, were reported in paddock near Temora in the NSW Riverina and two properties further north east near Canowindra in the NSW Tablelands.

Direct feeding damage by green peach aphid in canola. Images: Rob Fox


Acknowledgements

Thanks to the following for providing field observation: Stuart McColl (Kagome), Matt Bissett (Agrivision), Daniel Andrews (Nutrien Ag), Darcy Bullen (Western Ag), Andrew McMahen (Nutrien Ag), Nathan Soulsby (Agnvet), Heidi Gooden (Delta Ag), Rohan Brill, Tom Batters (Agrivision), George Hepburn (Tyler’s Rural), Rob Fox, Henry Mitton (Delta Ag), Brad Bennett (Agrivision) and Ben Romeo (Lachlan Fertilizers Rural).

 

Header image: Illustration by Elia Pirtle, cesar

PestFacts is supported by