Australian grain growers to take measures to reduce the impact of insect pests in next year’s crops

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.

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 over the summer and pre-sowing period can help increase the chances of a successful start next season.

PestFacts co-ordinator Kym Perry (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 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).

"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.”

Mr 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.

Mr 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, and this service will continue to be available over summer.

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.

For more information, contact Kym Perry on (08) 8303 9370, Ken Henry on (08) 8303 9540 or Gabriella Caon (08) 8303 9536.

The GRDC also provides growers with a comprehensive source of information in integrated pest management at www.grdc.com.au/pestlinks.