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Pasture day moth

Agronomist, Roger Garnsey (Roger Garnsey Agronomy), reports finding larvae of the pasture day moth (Apina calisto) in a perennial pasture near Braidwood, in the South Coast district of New South Wales. The paddock is to be sown with cocksfoot pasture, and there is some concern about the potential impact these caterpillars may have on the emerging seedlings. Roger says one large sized caterpillar was easily spotted about every 10m when walking across the paddock, and they appear to be feeding on sub-clover and some capeweed that is present in the paddock.

Pasture day moth caterpillars have a preference to feed on broadleaved weeds and will often leave cereals and grasses untouched where they have a choice in pastures. However, in paddocks where caterpillars are present and broad-leafed weeds are dead or dying from a previous herbicide spray, the grubs will transfer off the dying host plants and onto nearby plants.

Pasture day moth caterpillars are easily identified when they are fully grown by their dark brown to black colour and reddish-orange markings. They grow to about 50-60 mm long and have two prominent yellow spots near their rear end. From close up they are noticeably hairy, with prominent bristles. The adult moths are brown with yellow markings on the wings and orange on the body. The pasture day moth has only one generation per year and is found in most southern areas of Australia, ranging from lower Queensland to Tasmania.

In previous years, pasture day moth larvae have been found from late July onwards and have been recorded damaging pastures, some cereals and occasionally canola. Low numbers have been sighted in other places around the southern tablelands district recently, and Roger says they are often seen at this time of year in this region. Click here for images of pasture day moth caterpillars.

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