RESPONSES OF PAPAYA TO SHORT-TERM INSECTICIDAL OXYGEN ATMOSPHERE

Papaya (Carica papaya L., cv. Sunrise) fruits were exposed to a continuous flow of an atmosphere containing < 0.4% O2 (the balance being N2) for 0 to 5 days at 20C. Decay was a major problem, and some fruit had developed off-flavors after 3 days in low O2 plus 3 days in air at 20C. The intolerance of the fruit to low O2 correlates with an increase in the activity of pyruvate decarboxylase and lactate dehydrogenase but not with the activity of alcohol dehydrogenase. Insecticidal O2 (<0.4%) atmospheres can be used as a quarantine insect control treatment in papaya for periods < 3 days at 20C without the risk of significant fruit injury.