Development of a decision-support plan for wireworm management

Wireworms (Coleoptera: Elateridae) damage the eyes and young shoots of germinating setts in most mill areas. Liquid chlorpyrifos can be applied at planting to avoid damage. However, there are no guidelines for deciding on whether treatment is warranted, and a sampling method to detect wireworms before planting has not been developed. Trials in the Central and Herbert River districts in 1994 showed that crop establishment in most fields was not significantly improved by insecticide at planting. Baits were tested as a method for detecting wireworms in pre-plant fallows. Baits of rolled oats were chosen as the most suitable, being equally as effective as germinating seeds in 1994. In 1995 at Bundaberg, the reduction in crop establishment when treatment was withheld was positively correlated with the catch of wireworms at baits before planting, indicating that baiting could be used to develop a decision-support system for insecticide use. However, no similar relationship was seen at Mackay in 1995, perhaps because a greater time ,elapsed between baiting and planting in this district or because of variation in wireworm species between farms. Possible barriers to the adoption of baiting as a decision-support tool are discussed.