Sieving fruit pulp to detect immature Tephritid fruit flies in the field

Authors: RODA, AMY - Animal And Plant Health Inspection Service (APHIS); STECK, GARY - Florida Department Of Agriculture And Consumer Services; FEZZA, THOMAS - Animal And Plant Health Inspection Service (APHIS); SHELLY, TODD - Animal And Plant Health Inspection Service (APHIS); DUNCAN, RITA - University Of Florida; Manoukis, Nicholas; Carvalho, Lori; FOX, ABBIE - Animal And Plant Health Inspection Service (APHIS); Kendra, Paul; CARILLO, DANIEL - University Of Florida

Submitted to: Journal of Visualized Experiments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2023
Publication Date: 7/28/2023
Citation: Roda, A., Steck, G., Fezza, T., Shelly, T., Duncan, R., Manoukis, N., Carvalho, L.A., Fox, A., Kendra, P.E., Carillo, D. 2023. Sieving fruit pulp to detect immature Tephritid fruit flies in the field. Journal of Visualized Experiments. 197. https://doi.org/10.3791/65501.
DOI: https://doi.org/10.3791/65501

Interpretive Summary: Increasing the sensitivity and effectiveness of detection of tephritid larvae in the field can trigger earlier implementation of response efforts. Detecting late instar larvae was faster and more sensitive when mushing host fruit in a bag and passing the pulp through a series of sieves than hand cutting and visual inspection.

Technical Abstract: Fruit flies of the family Tephritidae are among the most destructive and invasive agricultural pests in the world. During eradication programs, a concerted effort is made to detect larvae, as this strongly indicates a breeding population as well as helps establish the spatial extent of the infestation. Detection of immature life stages triggers additional control and regulatory actions to contain and prevent any further spread of the pest. Traditionally, larval detection is accomplished by cutting individual host fruits and examining them visually. This method is labor intensive where only a limited number of fruit can be processed and the probability of missing a larva is high. Many countries undertake expensive eradication programs to eliminate incipient populations. An extraction technique that combines i) mushing host fruit in a plastic bag, ii) straining pulp through a series of sieves, iii) placing retained pulp in a brown sugar-water solution, and iv) collecting larvae that float to the surface was tested. The method was evaluated in Florida with field-collected guava naturally infested by Anestrepha suspensa. To mimic low populations more representative of a fruit fly eradication program, mangos and papaya in Hawaii were infested with a known, low number of Bactrocera dorsalis larvae. The applicability of the method was tested in the field on guava naturally infested by B. dorsalis to evaluate the method under conditions experienced by workers during an emergency fruit fly program. In both field and laboratory trials, mushing and sieving the pulp was more efficient (required less time) and more sensitive (more larvae found) than cutting fruit. Floating the pulp in brown sugar-water solution helped detect earlier instar larvae. Mushing and sieving fruit pulp of important tephritid hosts may increase the probability of detecting larvae during emergency programs.