Resistance of mexican fruit fly to quarantine treatments of high hydrostatic pressure combined with heat

High-pressure processing (HPP) has been proposed as an alternative quarantine method against the Mexican fruit fly Anastrepha ludens Loew (Diptera: Tephritidae), which is one of the most important pests infesting mangoes, citrus, and other fruits in Mexico and other Latin-American countries. However, processing conditions used to destroy eggs and larvae also affect the shelf life of fruits. The objective of this study was to assess the biological viability of A. ludens eggs treated with HPP, establishing whether undestroyed eggs were able to develop larvae, pupae, and adults capable of reproduction. Eggs of 1, 2, 3, and 4 days old were pressurized at 50, 75, or 100MPa for 0, 5, 10, or 20min. The hatching ability of pressurized eggs; survivorship of third instars, pupae, and adults emerged; and their capability to produce viable eggs were examined. The results showed that the hatching capacity of eggs and the larval development were affected negatively by the treatment duration and level of pressure. Treatments with 100MPa for 20min inhibited the hatching capacity of eggs of 2, 3, or 4 days old by 100%, but the inhibition was of 99.8% for 1-day-old eggs. Most of the eggs that survived the treatments were able to produce adults that can reproduce. The percent of hatching of eggs of A. ludens oviposited for adults obtained from pressurized 1-day-old eggs treated with 100MPa for 20min was 64.81%. Thus, more efforts must be addressed to destroy eggs and larvae during HPP because surviving organisms can reach adult stage and reproduce.