Low temperature phosphine fumigation for postharvest control of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae) on oriental lily

Abstract

Western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), widely distributed in the main Chinese cut flower production areas, present a problem because it is listed as a quarantine pest in some exporting countries. Phosphine (PH3), a potential alternative to methyl bromide (MB), was investigated to determine its effects on postharvest control of western flower thrips at low temperature on oriental lily. Toxicity tests showed that the 3-d-old egg was the most tolerant among all life stages. Phosphine concentrations from 0.31 to 1.88mgL−1 and exposure durations from 6 to 120h at 5°C were applied on the 3-d-old eggs, and results showed 24.34–09.55h were required to achieve 99% mortality with different phosphine concentrations. The expression of C0.85T=k was obtained. Synergistic effects of controlled atmosphere (CA) treatment with increased carbon dioxide (CO2) and reduced oxygen to PH3 fumigation were verified. Phosphine fumigation could achieve 100% mortality and had no adverse effects on vase life and damage indices of two oriental lily cultivars at 1.66mgL−1 PH3 and 12% CO2 for 16h, and at 2.29mgL−1 PH3 without CO2 gas for 2d at 5°C. All results suggested that low temperature phosphine fumigation with or without CO2 could be used as an alternative for postharvest control of western flower thrips on oriental lily.