PestFacts July 2022
Pasture webworm in cereals
Pasture webworm () (Hednota spp.) caterpillars have been reported around the Dutton, Truro and Eudunda areas in paddocks coming out of long to medium term grass pasture going into cereals.
Pasture webworm is a relatively minor native grass-feeding pest of pastures and can occasionally be an issue in cereals. They are only an issue in cereal crops following a pasture phase of several years. They feed at night and hide during the day in web-lined burrows. The larvae have smooth light to dark brown bodies and shiny dark heads. Older larvae have darker raised patches on each segment and look oily.
Monitor at night for caterpillar feeding, or during the day by careful digging at the base of recently damaged plants. Look for leaves protruding from tunnels.
Source of reports: James Chard (Growers Suppliers)
Black Portuguese millipedes moving
Black Portuguese millipedes () (Ommatoiulus moreleti) have been reported congregating around damaged faba bean plants and feeding on the rotting plant material near Laura. Initially, due to their conspicuous aggregation around damaged plants, they were considered a possible culprit but after some expert sleuthing, they were ruled out. We believe the damaged faba bean is attractive to millipedes, which like to feed on decaying organic matter.
Crop damage from black Portuguese millipede is relatively rare as they are primarily feed on decomposing organic matter such as leaf litter, damp decaying wood, fungi and plant roots, mosses and pollen. They have been recorded feeding on living plants, but the cause of this switch is poorly understood, and they can exist in high numbers without feeding on the crop. Often millipedes are conspicuous in the crop and are blamed for damage - always monitor to confirm what’s feeding!
How to monitor black Portuguese millipedes
Monitor activity, as well as densities, by searching at night with a torch to determine whether they are feeding on live plants. They are usually more prevalent in heavier soil types, heavy stubble or weed cover and in places where there were high populations in the previous spring. Preventative action, such as reducing stubble retention and removal of trash, is the main form of control to reduce numbers.
Source of reports: Ziek Kay (Platinum Ag Crystal Brook)
The latest information for growers and advisors on the activity and management of pests in all broadacre crops during the winter growing season.
