Host status of commercial mango cultivars to Thaumatotibia leucotreta (Lepidoptera: Tortricidae) in South Africa.

ABSTRACT

The objective of this study was to determine the host status of commercially cultivated mango fruit, Mangifera indica L. (Anacardiaceae) to Thaumatotibia leucotreta (Meyrick) (Lepidoptera Tortricidae) in South Africa. T. leucotreta was monitored with parapheromone traps in mango orchards in Limpopo and Mpumalanga from 2007 to 2010. Fruit were inspected for the presence of T leucotreta eggs in mango orchards. Mango fruit of the cultivars 'Tommy Atkins', 'Kent', 'Keitt', and 'Sensation' were artificially infested with T. leucotreta eggs on the tree to determine if the larvae were able to develop in fruit. Mature fruit of these cultivars were harvested and were then exposed to T leucotreta eggs and the larval development monitored. Before harvest, fruit were inspected for natural infestations and a packhouse survey was conducted during the 2009-2010 season to determine if any infested fruit were present. T. leucotreta was present in all mango orchards where monitoring was done with traps but no eggs were found on the fruit, which suggests the presence of antixenosis. Development occurred in mature harvested fruit of all cultivars that had been exposed to T. leucotreta eggs. Depending on the cultivar, between 0 and 5.05% of immature fruit on the tree supported development and demonstrate antibiosis. No naturally infested fruit were found in the orchards or during the packhouse survey. Mango in South Africa is not a natural host for T. leucotreta. Mature mango fruit is an acceptable host for T. leucotreta larval development under artificial conditions. The latex plays an important role in the resistance mechanism of mango fruit to T. leucotreta.