Published September 3, 2010

The Mudgee region is just outside the eastern boundary of one of the predicted plague locust risk zones, mapped on the Australian Dept. Agriculture, Fisheries & Forestry website. However many farmers further west, who grow the wheat for our bread and pasta, are likely to be seriously affected. With the next locust plague predicted this spring 2010, landscape-wide participation by landholders is needed to monitor and report egg beds to help target efforts to maximise effectiveness and minimise economic damage to agriculture and the environment. See links at end of the article for more information.

The Australian Plague Locust is well adapted to arid to semi-arid environments and can take great advantage of favourable seasonal conditions when they occur. Plagues occurred to some degree prior to introduction of European agricultural practices, however there is evidence that agriculture can encourage the formation of plague locusts. In fact, simplification of the landscape into larger patches of high density, high quality food (i.e. crops) is the key which turns these ‘split-personality’ insects from isolated grasshoppers into a swarm of adults.

Recent research by the University of Sydney has shown that “when reared alone, they develop into shy green grasshoppers which shun the company of others but when crowded they become brightly coloured, attracted by other locusts and form huge marching bands of juveniles and flying swarms of adults. The process of changing from the solitary to the ‘outgoing’ form is initiated by crowding, begins rapidly, and can accumulate across generations via a chemical agent added by the mother to her eggs. This transition is the catalyst for locust swarming (source: www.bio.usyd.edu.au).

Locusts are a great source of protein for many insects and animals. Spiders, parasitic wasps, snakes, birds, small mammals, lizards, scorpions, beetles and ants all use locusts as a food source. These guys can’t sit around waiting, in adequate numbers, for their once-a-decade feast to occur. Creating a permanent habitat for a range of critters throughout our food growing areas will help reduce the number eggs being laid, surviving to hatch, and transforming into the ‘outgoing’ locusts that become a plague.

• Latest news - www.daff.gov.au Department of Agriculture Fisheries & Forestry
• News releases - www.dpi.nsw.gov.au NSW Industry & Investment (Primary Industries)
• Spotlight - www.lhpa.org.au Livestock Health & Pest Authority