POSTHARVEST HEAT-TREATMENT OF RED GINGER FLOWERS AS A POSSIBLE ALTERNATIVE TO CHEMICAL INSECTICIDAL DIP

A postharvest treatment in hot water at 49 degrees C for 12 to 15 min eliminated >95% of ants, banana aphids and mealybugs infesting red gin ger flowers, Alpinia purpurata (Vieill.) K. Schum. In a 'systems-appro ach' to quarantine security, preharvest chlorpyrifos applications comb ined with either a postharvest hot-water immersion at 49 degrees C for 12 min or 5-min insecticidal dip in a combination of fluvalinate 2.0 flowable (F) and insecticidal soap eliminated all pests, including aph ids, mealybugs, thrips, soft scales, and ants. Phytotoxicity resulting from hot-water treatment was characterized by bract necrosis and shor tened vase life. Flowers were more susceptible to heat injury if harve sted during periods of high rainfall. Conditioning flowers in hot air at 39 degrees C for 2 h before hot-water treatment eliminated phytotox icity.