Oriental and Mediterranean Fruit Flies: Fumigation of Papaya, Avocado, Tomato, Bell Pepper, Eggplant, and Banana with Phosphine12

Abstract

Infestations (1- to 3-day-old eggs and larvae) of the oriental fruit fly, Dacus dorsalis Hendel, or the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were eliminated from packaged papayas, Carica papaya L., by low-temperature (12.8°C) fumigation with phosphine generated from ½ of a FUMI-CEL®. There were no survivors from 103,880 oriental fruit flies after an exposure of 4940 ppm-h. Where fumigations were done at 12.8° or 18.5°–26.1°C and 80% RH (ambient), mortality varied both with the natural logarithm of the concentration and treatment time because of the variable rates of phosphine generated. Time influenced efficacy more than concentration. The residues of phosphine in the fumigated papayas were 0.08 ppb after low-temperature fumigation and an exposure of 7600 ppm-h. These residues dissipated to trace levels after 2 days of storage at 12.8°C. Residues were 1.0–1.4 ppb after fumigation at ambient and an exposure of 7700–9100 ppm-h. These residues decreased to 0.18–0.3 ppb after 1 day of storage. Residues of 1.3 ppb on the carton and the polyethylene foam sheet dissipated to levels ranging from trace to 0.4 ppb. Papayas and 10 Hawaiian varieties of avocado, Persea Americana Mill., were not injured by low-temperature fumigation, but fumigated avocados ripened faster than unfumigated avocados. ‘California Wonder’ bell peppers, Capsicum annuum L. var. annuum, ‘apple’ and ‘Williams Hybrid’ bananas, Musa paradisiaca ssp. sapientum (L.) O. Ktze., ‘N-52’ and ‘Anahu’ tomatoes, Lycopersicon esculentum Mill., and 5 varieties of avocado were uninjured after fumigation for 12–63 h and exposures of 5500–20,000 ppm-h at ambient. ‘Black Beauty’ eggplant, Solanum melongena L., tolerated 5500 ppm-h.