Mandalotus weevils active

Date: 03 Jun 2011

MANDALOTUS WEEVILS ACTIVE: As Mandalotus weevils become active in parts of South Australia’s grain belt, growers are advised that early detection is critical in preventing and reducing damage to germinating crops. According to the South Australian Research and Development Institute (SARDI) Entomology Unit, the weevils have been reported actively feeding in the Murraylands and on Yorke Peninsula. SARDI entomologist Kym Perry says growers on rubbly or lighter calcareous soil types should now be regularly checking germinating crops, especially canola, for plant damage or losses and the presence of adult weevils. “Adults are known to attack seedlings of canola, lentils, beans, cereals, and medic pasture, with canola most susceptible to serious damage,” said Mr Perry, whose work is supported by growers and the Australian Government through the Grains Research and Development Corporation’s (GRDC) investment in the National Invertebrate Pest Initiative (NIPI). “Adults often ringbark the stems of canola and lentils above ground level, resulting in plant losses and bare patches. In severe cases they can destroy large areas which will need to be re-sown. In cereals, most damage occurs on leaves which are chewed or lopped to the ground where weevils continue feeding.” Growers should consult with their local agronomist regarding the need for treatment. Meanwhile, the SARDI Entomology Unit is conducting GRDC-funded research to increase understanding of the biology of Mandalotus and is asking growers and advisers to report any sightings and to send in multiple specimens along with observations. Mr Perry says little is known about the pest’s basic biology, but hopes the study will reveal the identity of species involved, the life history, host range and mode of arrival into crops – information which is critical for developing effective management strategies. Growers who find weevils can contact Mr Perry on (08) 8303 9370 or, or Gabriella Caon on (08) 83039 3536 or Specimens can be sent to NIPI Insect Diagnostic Service, SARDI Entomology Unit, GPO Box 397, Adelaide 5001.


Caption: Mandalotus attacking emerging lentil seedlings. Image courtesy SARDI.

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