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Australian plague locust hatchings

We have received unconfirmed reports of early hatchings of Australian Plague Locusts (Chortoicetes terminifera) near Swan Hill, in the Mallee district of Victoria. It is anticipated that further hatchings could occur as early as this weekend around Mildura, also in the Mallee district of Victoria. In New South Wales, early hatchings of nymphs have occurred near Nyngan, in the Central West Slopes and Plains district. Growers around these areas should inspect their properties, while in other regions growers should be aware that the APLC has revised hatching dates in many parts.

Temperatures during late winter were generally below average, while continued rainfall has kept soils moist. Together these conditions have resulted in low soil temperatures, leading to later predicted hatching dates in many areas, The APLC has left peak hatching dates for the Mallee areas unchanged, while in central Victoria, locusts are expected to emerge about 10 days later than previously forecast. For New South Wales, the estimated peak hatching dates have been put back by 7-9 days in the Riverina, while in the Central West Slopes and Plains district dates have been delayed by 1-2 weeks, and by approximately 1 week in the South West Slopes region. For the updated forecast hatching and development dates, click here.

Heavy rainfall and flooding recently experienced in Victoria and southern New South Wales could further delay hatching dates. However, there are unlikely to be any major impacts on egg viability in flood-affected areas. Waterlogging could have an effect just prior to hatching, in terms of depriving locusts of oxygen, exposing eggs to predators and making them more susceptible to fungi and other diseases. According to the APLC, this is not expected to significantly reduce the overall number of locusts that hatch in the coming months.

Locust eggs are laid within the soil in a pod, which is sealed with a frothy plug to protect eggs from desiccation, fungal pathogens and other potentially harmful factors. In sandy soils, egg embryo development appears to be occurring faster than in predominantly clay soils. Because of continued repeated rainfall, the soils, particularly heavy soils, are remaining wet, and therefore not warming as quickly in response to increases in ambient temperature. Growers should be aware that hatching of locust nymphs could vary across their properties, depending on soil type. For further information visit the APLC website.

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