Hot-air induced thermotolerance of red ginger flowers and mealybugs to postharvest hot-water immersion.
The vase life of Alpinia purpurata flowers subjected to postharvest hot-air conditioning (40°C, 64% RH) for 2 h prior to hot-water immersion (49° for 12 min) equalled or exceeded the vase life of flowers treated with hot-water immersion only and control flowers in 96% of the trials conducted over one-year. Reduced flower quality (marketability) (13% of trials) and reduced vase life (4% of trials) from hot-air and hot water treatments occurred in months with high rainfall (≥ 58 cm/month) or drought (≤ 5 cm/month). Flowers conditioned in hot air before hot-water immersion tolerated 49° 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 citrus mealybug (Planococcus citri) survival by 0.4 (2 h hot air + hot water treatment) and 40% (4 h hot air + hot water treatment).