Effect of cold storage on larval and adult Anastrepha ludens (Diptera: Tephritidae) viability in commercially ripe, artificially infested Persea americana 'Hass'

Commercially ripe 'Hass' avocados, Persea americana Mill, artificially exposed to wild Anastrepha ludens (Loew) (Diptera: Tephritidae) females 24 h after harvest were placed in a cold storage facility to determine the effect of low temperature on larval survival and adult viability. Fruit were left for 3, 6, 9, and 12 d in a cold room at 5 degrees C followed by a 20-25-d period at ambient temperature to allow for larval development and pupation. Hass avocados and grapefruit, Citrus paradisi Macfadyen, maintained at ambient temperature served as controls. Overall, only 0.23% of the Hass avocados and 19.30% of the grapefruit were infested. The number of infested fruit increased with decreasing exposure time to cold. Puparia from cold-treated Hass avocados were significantly smaller than those stemming from cold-treated grapefruit. Hass avocados exposed for 12 d to 5 degrees C yielded no puparia, and those exposed for 6 and 9 d yielded 22 and two puparia, respectively, but no adults. Although Hass avocados exposed to cold temperature for 3 d yielded adults that reached sexual maturity (N = 16), females laid inviable eggs. Grapefruit exposed to cold for 12 d yielded normal-sized puparia (but no adults), whereas those exposed over 9 d yielded females able to lay viable eggs. We conclude that exposing fruit to cold storage after packing and during transport represents an effective risk-mitigating procedure in the highly improbable event that a gravid A. ludens female might lay eggs in a commercially ripe Hass avocado that had been left unprotected in a packinghouse.