B. K. S. Hu

Molluscicides and mechanical barriers against slugs, Vaginula plebeia Fischer and Veronicella cubensis (Pfeiffer) (Stylommatophora: Veronicellidae).

Thirteen molluscicides containing metaldehyde, three molluscicides containing metaldehyde plus carbaryl, one molluscicide containing metaldehyde plus methiocarb and one molluscicide containing methiocarb alone were tested for efficacy against the brown slug, Vaginula plebeia Fischer, and the two-striped slug, Veronicella cubensis (Pfeiffer). With the exception of Corrys Liquid Slug, Snail and Insect Killer against V. plebeia, all tested molluscicides caused significant mortalities against both species. Selected molluscicides were further evaluated for persistence under simulated rainfall; Deadline One Last Meal for Slugs and Snails, Deadline 40, Deadline Bullets and Slug and Snail AG Pelleted Bait, all of which contain metaldehyde as the active ingredient, consistently produced high mean percentage mortalities against both species. Efficacy of certain molluscicides decreased steadily with time, whereas efficacy of other molluscicides increased initially before declining. Mold grew on the majority of molluscicides after application. Liquid paste and liquid formulations were more resistant to mold development than pelleted, granule or coated granule formulations. In a separate study, physical barriers composed of copper or fiberglass screens repelled both slug species.

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

Abstract Vase life of red ginger flowers, Alpinia purpurata (Vieill.) K. Schume, subjected to postharvest hot-air conditioning (40°C, 64% r.h.) for 2 h prior to hot-water immersion (49°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 hot-air and hot water treatments occurred in months with high rainfall (≥58 cm month−1) or drought (≤5 cm month−1). Flowers conditioned in hot air before hot-water immersion tolerated 49°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%.

Postharvest heat treatment of red ginger flowers as a possible alternative to chemical insecticidal dip

Abstract A postharvest treatment in hot water at 49 °C for 12 to 15 min eliminated > 95% of ants, banana aphids and mealybugs infesting red ginger flowers, Alpinia purpurata (Vieill.) K. Schum. In a ‘systems-approach’ to quarantine security, preharvest chlorpyrifos applications combined with either a postharvest hot-water immersion at 49 °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 aphids, mealybugs, thrips, soft scales, and ants. Phytotoxicity resulting from hot-water treatment was characterized by bract necrosis and shortened vase life. Flowers were more susceptible to heat injury if harvested during periods of high rainfall. Conditioning flowers in hot air at 39 °C for 2 h before hot-water treatment eliminated phytotoxicity.

Postharvest heat treatment of red ginger flowers as a possible alternative to chemical insecticidal dip: [Postharvest. Biol. Technol. 7 (1996) 137–144]

Abstract A postharvest treatment in hot water at 49 °C for 12 to 15 min eliminated > 95% of ants, banana aphids and mealybugs infesting red ginger flowers, Alpinia purpurata (Vieill.) K. Schum. In a ‘systems-approach’ to quarantine security, preharvest chlorpyrifos applications combined with either a postharvest hot-water immersion at 49 °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 aphids, mealybugs, thrips, soft scales, and ants. Phytotoxicity resulting from hot-water treatment was characterized by bract necrosis and shortened vase life. Flowers were more susceptible to heat injury if harvested during periods of high rainfall. Conditioning flowers in hot air at 39 °C for 2 h before hot-water treatment eliminated phytotoxicity.