Pulses: integrated hit against pests

NORTHERN RESEARCHERS are notching up some major wins over pest problems in pulses.

Supported by growers and the Federal Government through the GRDC, a dedicated pulse Integrated Pest Management team of Queensland Department of Primary Industries (QDPI) researchers is coming up with some coordinated strategies against mirids, heliothis and other insect pests.

Project leader Hugh Brier said that the team had developed break-even thresholds for spraying and sampling techniques for mirids in mungbeans. Close collaboration with the Australian Mungbean Association, Pulse Australia and QDPI extension officers had enabled rapid adoption of this research.

Heliothis warning

"Trials to date clearly show that the current mirid pesticide for pulses (dimethoate) greatly increases the risk of subsequent heliothis attack," Mr Brier said.

"In some trials, total pest activity post-spray (bugs plus caterpillars) was no different to that in unsprayed plots;' he said. "So softer and more selective pesticides for mirids are urgently needed to conserve natural predators of heliothis, while at the same time effectively controlling bugs and mirids where required. This issue has also been raised by consultants, who have flagged the need for multi-pest management strategies and multi-pest thresholds."

Mr Brier said the project had already generated data that had been submitted for registration of an effective and more selective new-generation pesticide, with dual miridlheliothis activity.

(Bio-controls for heliothis were featured in Issue 37 (November) of Ground Cover.)

Go easy on sprays and watch for exotic pests

The project has also shown that dimethoate can be used at significantly lower rates, which are still effective against mirids, but have much less impact on beneficial insects. Trials this coming season will generate further data before this approach is formally approved.

The team is also evaluating potential soft options against pod-sucking bugs.

"There's an ongoing need for genuinely soft approaches to minimise the impact of recently arrived exotic pests, in particular silverleaf whitefly and soybean aphids in soybeans, and the western flower thrip, which can introduce flaring tomato spotted wilt virus, a devastating disease of peanuts," Mr Brier said.

Program 3 Contact: Mr Hugh Brier 0741600740

Region North