The Australian Grains Research and Development Corpoation (GRDC)has reported on the phenomenon of mouse plagues in South Australia, and how an increase in the frequency of these epidemics is an unexpected side effect of an increase in minimum tillage in cereal production.
According to this GRDC research update, mouse plagues were recorded in South Australia as early as 1890: “the land swarms with mice; they destroy or damage everything that is eatable; a large quantity of the sown grain has been devoured; no crop is expected from over 100 acres; the farmer will not resow now it is so late - Kapunda Herald, June 1890”.
There has, however, been a marked increase in plague frequency in the last 30 years. On average a plague was recorded somewhere in South Australia every 5-6 years between 1900 and 1980, but every 4 years since then, with severe plagues in 1980, 1993, 2010 and 2011. In addition, substantial localised damage occurred in several other years and some growers have had to bait every 2nd year for the last decade.
The increased frequency of plagues has been caused by changes in cropping systems that use less cultivation, stubble retention, more diverse crops, and fewer livestock. These changes provide mice with better cover, more high-quality food, undisturbed burrows and easy access to sown grain. The end result is both more mice for any given seasonal conditions, and more damage to crops for a given number of mice.
Read the full update here.