Effects of larval‐diet pH on worker comfort and insect quality during mass production of mediterranean fruit fly (Diptera: Tephritidae) in Hawaii¹

Mention of a proprietary product does not necessarily imply its endorsement by the USDA.

Abstract

During mass production of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), for the 1980–82 California Sterile‐Insect Technique (SIT) program, the production of volatiles by excessive fermentation in the diet caused eye and lung irritation to workers and heavy corrosion to air conditioners. Subsequent laboratory analysis of the air identified acetic acid and CO₂, as the primary causal agents. Concentrations of these volatiles in the air were reduced from ca. 16.5 ppm to 10 ppm when the initial diet pH was lowered from 5.8 to 4.5. However, the adjustment was coincident with noticeable irregularities in pupal recoveries and larval developmental time. The biological effects of three initial larval‐diet pH's (3.6, 4.6, and 5.6) on mass‐produced C. capitata were investigated. Decreasing the pH resulted in three undesirable consequences: decreased pupal recovery, decreased pupal weight, and increased larval developmental time. Substitution of citric acid for hydrochloric acid in the diet did not affect C. capitata quality.

Key words:

• Mediterranean fruit fly
• mass production of fruit flies
• larval diet pH

Notes

Mention of a proprietary product does not necessarily imply its endorsement by the USDA.