Survival of Australian plague locust eggs in relation to soil type and moisture retention
Dr Martin Steinbauer – Australian Plague Locust Commission, Canberra
• Locust egg survival is affected by moisture content and is a key to understanding population changes.
• A locust egg is able to exert up to 1000kPa suction to extract moisture – if soil water potential is greater egg will die.
• A WP4 can be used to measure the soil water potential for a given soil type and moisture content.
Locust eggs laid in intimate contact with their host soil – moisture critically important
(photo courtesy of Barry Davies Department of Agriculture & Food WA)
First egg survival versus moisture content relationship for C. terminifera
• Survival of eggs falls below 50% on vermiculite with < 20% water
• Used a dewpoint potential meter to determine the suction required to extract water from vermiculite at 20% and less moisture
• Repeat egg survival assays & suction measurements for different soils in which locusts lay their eggs
WP4 Dewpoint PotentiaMeter™
• Water potential readings directly in MPa within 5 minutes
• Directly measures water potential from 0 to -60 MPa
• Easy to use
• Push-button calibration using standard samples
• Accuracy: -0.1MPa on samples from 0 to -10MPa; 1% accuracy from -10 to -60 Mpa
• Standard RS232 output: For data capture via computer or printer. Cable included.
• This presentation based on “Physiological adaptations of locusts: examples from South African and Australian species” by Dr Martin Steinbauer – Australian
Plague Locust Commission, Canberra
• Used with permission and grateful thanks