Winter wheat pest weeded out

Winter wheat pest weeded out

A University of Queensland researcher believes a control has been found for a grass weed which can reduce winter wheat crop yields by as much as 25% in Australia's northern grain region.

Ian Taylor, a PhD student, has spent the last two years researching the biology of paradoxa grass, both at the University's Gatton College and in England last year as a Sir Robert Menzies scholarship recipient.

He believes tilling the soil before seasonal planting, along with chemicals already used by farmers, could substantially eliminate paradoxa, the second most prominent grass weed in winter cereals in the north.

"It is particularly difficult to control because more than 21,000 seeds are produced by each plant, they emerge at several different times during the life of a wheat crop, and resistance to some herbicides has been detected," Mr Taylor said.

Working with Dr Nick Peters, the principal weed biologist at Long Ashton Research Station in Bristol, England, Mr Taylor investigated the effects of different light on seed germination and dormancy, and the effect of temperature on secondary dormancy.

They found dormancy could be overcome by exposing seed to white or red light after it had been buried, so the best way to control paradoxa grass was to till soil at the start of the winter wheat growing season.

"We can then use tillage to shift emergence from throughout the season to having the majority of seed germinate at the beginning of the season, which allows us to make more efficient and better use of our herbicides," Mr Taylor said.

"We found that without tillage emergence at the beginning of the season was 400 plants per square metre, but when we used a tillage treatment 1800 plants per square metre emerged.

"As the season progressed we had higher emergence later out of the non-tilled plot, while in the tilled plot the emergence was much greatly reduced.This means we can come in clean up at the beginning of the season, and the paradoxa grass plants that come in later in the season will compete less with the established wheat crop."

For further information, contact Mr Taylor on (07) 3365-4814 (Mondays and Fridays), (07) 3365-0271 (Tuesdays and Wednesdays), or 4639-8838 (Thursdays and Saturdays).