The younger instars or stage of growth (there are six instars as caterpillars) chew the leaves and may leave scalloped edges.

The younger instars or stage of growth (there are six instars as caterpillars) chew the leaves and may leave scalloped edges.

THERE are reports of thriving armyworm populations in pastures in some areas in South Gippsland.
Department of Economic Development, Jobs, Transport and Resources (DEDJTR) Pasture and Fodder Conservation Specialist, Frank Mickan is urging producers not to be complacent because there could be more outbreaks around Gippsland soon.
“Producers need to manage the risk of infestations, as feed will be in short supply as it is, without feeding these destructive caterpillars too,” Mr Mickan said.
“Armyworms tend to set up camp initially in pastures shut-up for hay and can decimate crops within days.
“This season already has seen a producer lose a crop of lucerne overnight and in the last infestation year, 2013, one producer lost about 60 per cent of his standing hay crop.
“If you have had trouble with armyworm caterpillars (or larvae) in the past, inspect pastures (or cereal crops) to pick up early signs of their presence. Check the longer pastures first.”
Armyworms are most active at night so sweeping with a sweep-net/bucket at dusk will be the most effective.
Sweep about 100 times across the crop in 180 degree arcs, at different sites within the crop to give an indication of density and spread.
“If average catch is more than 5-10 per 100 sweeps then hop onto your knees to do at least ten “spot checks” in the crop and consider spraying if one to three caterpillars per square metre is detected,” Mr Mickan said.
“There are chemicals registered for control of armyworms so if the caterpillars are “marching” in bands spray the band but also overlap spraying to cover where they were and where they are heading to, just to be sure!
“If spraying is necessary, it is recommended to do it in late afternoon or early evening for maximum effect.
“When the food supply (pastures/cereals) becomes severely depleted, the caterpillars start to gather together and they will “march” across paddocks in search of food, hence the name armyworm.”
Three species of armyworm (Common, Southern and Inland Armyworms) exist in southern Australia but all look the same as caterpillars and all do similar damage.
For more information go to www.agriculture.vic.gov.au and search for armyworms.