Fumigation of kumara with aerosol formulations of synthetic and natural pyrethroids for control of tropical armyworm and opogona

Tropical army worm (TAW) and opogona are common pests of stored kumara. In Northland, stored tubers became infested with TAW predominantly after harvest early in the year whilst opogona damage is more prevalent later in the year. Current practices for controlling these pests include repeated use of organophosphate (OP) insecticides that are hazardous to apply. Moreover, these pests are becoming more resistant to OP pesticides following the excessive use of these chemicals. Consequently, residues in kumara have become a concern to growers. This project investigated alternative pesticides and assessed the associated risk of residues from their use.