Combining chlorpyrifos and diflubenzuron for effective management of clover flea (Sminthurus viridus)

Abstract

Clover flea (syn Lucerne flea) (Sminthurus viridis) populations were controlled in pasture in Northland over spring with a single application of insecticide A mixture of organophosphate insecticide (chlorpyrifos) at a range of rates (125 to 100 g/ha) combined with an insect growth regulator (diflubenzuron) at 125 g/ha was applied to small plots in two locations in spring 2000 Field scale demonstration plots were treated with chlorpyrifos at 125 g/ha combined with diflubenzuron at 125 g/ha at nine sites in spring 2001 In small plots (2000) chlorpyrifos alone and with diflubenzuron reduced the clover flea populations by 98 within 24 48 h regardless of rate Plots treated with diflubenzuron alone had 67 fewer fleas than untreated ones at this time No differences existed between insecticide treatments 3 12 weeks after spraying In the demonstration plots (2001) clover flea numbers were maintained at low levels for at least 33 days over the spring season Cost health and environmental advantages may accrue from the reduced use of organophosphate insecticide