Cold treatment for guava fruits infested with oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

Abstract

Guava (Psidium guajava Linnaeus) is an important horticulture crop in tropical and subtropical regions. However, guava transportation to the fruit market is regulated due to the risk of fruit fly infestations. The oriental fruit fly [Bactrocera dorsalis (Hendel), Tephritidae, Diptera], which damages numerous horticulture fruits, is the primary pest in guava. For fruit export, phytosanitary treatment is necessary to prevent the potential oriental fruit fly infestations through pest-infested fruits. In this study, cold treatment was administered to eliminate oriental fruit fly infestations in guava fruits. The optimal egg inoculation density was 200 eggs per fruit, and third instar larvae displayed the highest cold treatment tolerance. On assessing the efficacy of cold treatment, none of the third instar larvae in the fruits survived at a constant fruit core temperature of 0.5–1 °C for 11 days. A confirmatory test revealed that on maintaining a fruit core temperature of 0.5–1 °C for 12 days, 100% mortality was achieved among the fruit flies. In fruit quality assessment, guava fruits exposed to cold treatment still maintained their market value. Thus, cold treatment effectively disinfested guava fruits with possible fruit fly infestations, making it a viable quarantine treatment for guava fruits prior to their export.