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Reducing the Impact of Insects in Next Year’s Crops

17 December 2010
The Australian Bureau of Agricultural and Resource Economics and Sciences

South Australian and Western Victorian grain growers are being encouraged to take measures over the coming months to reduce the impact of insect pests in next year's crops, according to the

PestFacts South Australia and Western Victoria co-ordinators say that cultural practices have a significant impact on insect populations in field crops. And a number of basic steps can help increase the chances of a successful start next season.

PestFacts co-ordinator Kym Perry also of the SA Research and Development Institute Entomology says controlling summer weeds is a pest management priority.

"Summer weeds provide a ‘green bridge' for pests such as aphids, mites, snails and diamondback moth to survive on over the hot summer months," said Perry.

"These over-summering populations give rise to new generations the following autumn which can then move into emerging crops. Controlling summer weeds removes habitat and food supply, reducing pest survival and limiting local sources of infestation for crops in autumn."

Perry recommends that growers identify paddocks at higher risk of pest pressure and carefully monitor them in the autumn prior to sowing susceptible crops. Some risk factors include:

  • High pest pressure this season, or a history of recurring or resident pests such as cockchafers and false and true wireworms;
  • Sowing crops into paddocks following a pasture phase or adjacent to long term pastures;
  • Areas containing or adjacent to high weed populations which may harbour pests;
  • Crops intended to be sown which are particularly susceptible to seedling damage (such as canola);
  • Significant pest numbers detected during autumn monitoring of paddocks prior to sowing.
Perry said growers could monitor insect pests through techniques such as pitfall traps and shelter traps for ground-dwelling or nocturnal feeders, germinating seed baits, and digging in the soil to detect soil-dwelling larvae.

"Remember to sample a number of representative areas within the paddock. If pests are detected which are likely to cause significant damage at emergence, consider the use of seed dressings or rotating with a less susceptible crop," he advised.

SARDI Entomology Unit offers a free insect diagnostic service for PestFacts subscribers. For identification, growers and agronomists should send at least two undamaged specimens in a non-crushable container along with some food (host material). Provision of collection date, district, host-plant, description of damage caused and contact details is requested. Specimens can be forwarded to: Kym Perry or Gabriella Caon, Entomology Unit SARDI, GPO Box 397, Adelaide 5001.

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