Attractiveness of Different Coloured Sticky Traps to the South African Citrus Thrips (Scirtothrips aurantii Faure) in Avocado, KwaZulu-Natal, South Africa

Abstract

The South African citrus thrips, Scirtothrips aurantii, is a recently confirmed economic pest in South African avocado. Scarring damage by thrips results in corky tissue development, making the fruit unsuitable for export and potentially costing the country in lost export revenue. Thrips management is complicated by the multiple and protracted flowering patterns of susceptible cultivars. In addition, widespread pesticide resistance of thrips and the negative environmental effects along with minimum residue levels for export fruit limit the application of pesticides for thrips control. Monitoring an insect pest's presence and abundance is the first step in thrips management. This study aimed to investigate S. aurantii's colour preferences, establish the distribution of thrips in the orchard and population dynamics from flowering to fruit establishment. Attractiveness followed the order yellow > blue, white, clear > red, black, purple and orange. Thrips were evenly distributed throughout the orchard, with the highest populations occurring during flowering (August), declining sharply and picking up in the summer months starting December. Yellow sticky cards are recommended as a monitoring tool.