Hot-air induced thermotolerance of red ginger flowers and mealybugs to postharvest hot-water immersion

Vase life of red ginger flowers, Alpinia purpurata (Vieill.) K. Schume, subjected to postharvest hot-air conditioning (40 degrees C, 64% r.h.) for 2 h prior to hot-water immersion (49 degrees C for 12 min) equaled or exceeded the vase life of red ginger treated in hot-water immersion only and control flowers in 96% of the trials conducted during a one year period. Reduced flower quality (marketability) (13% of trials) and reduced vase life (4% of trials) from her-air and hot water treatments occurred in months with high rainfall (greater than or equal to 58 cm month(-1)) or drought (less than or equal to 5 cm month(-1)). Flowers conditioned in hot air before hot-water immersion tolerated 49 degrees C water for up to 13 min, exceeding a proposed 12 min treatment time with no significant loss in vase life or marketability. No apparent benefits were observed for conditioning flowers longer than 2 h in hot air. Hot-air conditioning prior to hot-water immersion increased mealybug survival by 0.4-40%. (C) 1997 Elsevier Science B.V.