Non-chemical post-harvest disinfestation of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) in tommy atkins mango using hot-water immersion treatment.
Mango production and trade is a major source of employment, food and income in Sub Saharan Africa (SSA). Most of its production in SSA is under smallholder farming with a few commercial farms undertaking production. Fruits are traded both locally and some exported, with improved exotic varieties being preferred by consumers. However, mango export which is more lucrative to most exporters in terms of foreign currency exchange earnings, is currently faced with serious quarantine restrictions because of the invasive fruit fly, Bactrocera dorsalis. Since its invasion in Africa, yield losses of up to 100% have been recorded. In addition, loss of export due to restrictions has resulted in loss of potential revenue from lucrative markets such as the European Union. This study aimed at determining postharvest disinfestation parameters for B. dorsalis using hot-water treatments. To attain this, the development of B. dorsalis in the mango cultivar Tommy Atkins was determined. This information was used to treat different immature life stages at 46.1°C for 12, 24, 36, 48, 60 and 72 min. Mortality of the different life stages over the different duration of treatments was determined. There was an increase in mortality with increasing duration of treatment for all life stages. The egg and first instar life stages were the most heat susceptible stages followed by the second instar larvae. The third instar was the most heat tolerant life stage evaluated and required treatment at 46.1°C for 86.7 min (95% CL (77.830-99.880)) to achieve 100% mortality. Validation experiments at this temperature and treatment duration resulted in no survivors from the 41 542 third instar larvae treated in Tommy Atkins weighing 500-700 g. These results provide an effective treatment protocol which can be adopted by exporters in re-accessing currently inaccessible lucrative export markets in the U.S.A. and Europe.