Susceptibility of Avocado Fruit to Scirtothrips aurantii Faure (Thysanoptera: Thripidae) and Wind Scarring Damage in Limpopo and KwaZulu-Natal Provinces of South Africa

Abstract

In South Africa, the avocado (Persea americana) is an important fruit, grown primarily for export and contributing ZAR 1.75 billion to the gross domestic product of the country. As an export driven industry, optimising exportable avocado fruit volume is a primary concern. Wind induced abrasion and damage by thrips (Thysanoptera: Thripidae), through their feeding on avocado fruit results in corky tissue development (scarring) and making the fruit unsuitable for export. The study aimed to determine the economic losses caused by these agents as well as assess different cultivar responses to scarring damage. Across cultivars, the 1.49% revenue annually due to Scirtothrips aurantii downgrading (3.86% loss factor), translating to ZAR 34.90 million (US$2.39 million). Packhouse study results showed that both thrips and wind abrasion damage accounted for 30% scarring damage, a loss factor of 13.72% and a combined revenue loss of 5.57%. The cultivar ‘Pinkerton’ showed the greatest susceptibility to scarring damage by both wind and S. aurantii whilst the cultivar ‘Carmen®-Hass’ showed a natural predisposition to higher levels of thrips damage. The presence of macadamia trees near avocado trees predisposes avocado fruit to S. aurantii damage.