Efficacy of phosphine fumigation of apples for codling moth ( Cydia pomonella ) disinfestation

Codling moth, although rare on New Zealand export pipfruit, is a quarantine actionable pest that limits access to countries where it is not present and requires speciic control measures during production. Fumigation with phosphine gas is a disinfestation technology that has recently been extended to fresh produce. Apples infested with codling moth ifth instar larvae and eggs were fumigated for two durations at concentrations from 500 to 3500 ppm phosphine at two temperatures. Larval mortality assessed 3 days post fumigation at 0.5°C increased with increasing dose, with little difference between 48- and 72-h treatments. In contrast, mortality after fumigation of larvae at 12°C did not increase with dose and resulted in overall higher mortality than 0.5°C. Codling moth eggs were more susceptible to fumigation at 0.5°C than at 12°C; fumigation at 12°C had minimal effect at all doses. The implications for improved market access using phosphine fumigation are discussed.