- A B Ware, B A Tate, P R Stephen, J H Dancel and R R Beck
- Citrus Research International (Pty) Ltd. PO Box 18, Nelspruit 1100, South Africa
- 2004
Young (first and second instar) and mature (third instar) Mediterranean (Ceratitis capitata) and Natal (Ceratitis rosa) fruit fly larvae were subjected to various periods of cold (0.5°C) and the numbers surviving the treatments were determined. Probit analysis on the data indicated that mature Natal fruit fly larvae were the most tolerant. It is recommended that the medium and large scale trials necessary to determine the effectiveness of the disinfestation treatment be done using this life stage, unless the country for whom the research is being conducted insists on both species being processed.
Summary:
The study investigated cold treatment (0.5°C) effects on Mediterranean fruit fly (Ceratitis capitata) and Natal fruit fly (Ceratitis rosa) larvae in litchis.
Larvae of different developmental stages (young: 1st and 2nd instar, mature: 3rd instar) were tested for survival after cold exposure.
Probit analysis showed mature Natal fruit fly larvae were the most cold-tolerant stage among those tested.
For practical disinfestation trials, it is recommended to use mature Natal fruit fly larvae as the target life stage to optimize effectiveness and cost.
Fruit flies cause quarantine concerns worldwide, and cold treatment is a common quarantine method requiring a mortality rate of at least 99.996832% (probit 9).
Methodology included inoculating litchis with eggs, incubating to desired larval stages, and subjecting them to controlled cold exposure, followed by survival assessments.
Results indicated variation in mortality among eggs, young larvae, and mature larvae, with eggs initially appearing most tolerant but practical considerations led to focusing on larvae.
Findings aim to assist export protocols and quarantine treatment standards for litchis to ensure pest-free produce for international markets.