INSECTICIDES FOR CONTROL OF GREYBACK CANEGRUB IN NEW PLANTING SYSTEMS

SOME canegrowers are adopting new planting configurations, including the use of minimum-tillage planters and dual-row beds, which may impact on the efficacy of current insecticide registrations for canegrub control. We conducted efficacy trials against greyback canegrub in the Central and Herbert districts, to evaluate the impact of these changes and to obtain data to alter existing registrations if required. The controlled-release insecticide granules suSCon® Blue and suSCon® Maxi gave satisfactory control of greyback canegrub when applied between the discs of a doubledisc opener planter, although suSCon® Blue efficacy may have been compromised in one trial with a soil pH near 6. Confidor® Guard gave at least one year of control of greyback canegrub in dual rows when applied at planting or using coulters. Twin coulters were slightly more effective than a single coulter. Effective application rates of suSCon® granules and Confidor® Guard in dual rows were within the range currently listed on the registered labels for single-row application when expressed per hundred metres of single- or dual-row bed. Results have been reported to the relevant insecticide companies and an application for a change to the current suSCon® Maxi label to include dual rows and double-disc opener planters is currently with the Australian Pesticides and Veterinary Medicines Authority (APVMA).