The occurrence, cost and control of sawfly larval (Lophyrotoma interrupta) poisoning of cattle in Queensland 1972-81.

A postal survey of cattle producers in the Maranoa, Warrego and Leichhardt districts of Queensland where poisoning of cattle by larvae of the sawfly (Lophyrotoma interrupta) occurs was carried out in 1982 with 179 replies (64% of those contacted). During 1972-81, 50 farms with 84,300 cattle experienced deaths (5254 on 37 farms) during July to September. The worst years were 1975 (955 deaths) and 1979 (1895 deaths). Heavy losses occurred on 9% of farms. These were where the silver-leaved iron bark (Eucalyptus melanophloia) was most common. To prevent the disease, 37 graziers moved cattle from dangerous areas and 52 partly removed E. melanophloia from their farms. 31 fed supplements to try to prevent the pica thought to cause cattle to eat larvae. 53 who had suffered sporadic or no deaths took no action. The survey results indicated that cattle should not be returned to dangerous areas until early October. The estimated total yearly cost from reduced carrying capacity, control measures and deaths was $1,100,000 (1981 values). Improved control by advice on property management and a better knowledge of the population dynamics of the sawfly was suggested. The use of antidotes or toxoids was thought inappropriate.