Response of New Zealand flower thrips, Thrips obscuratus (Crawford), to olfactory and visual stimuli: A dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Horticultural Science with Honours at Lincoln University

Abstract

White sticky traps of five sizes (210 x 280, 150 x 195, 105 x 140, 75 x 95 and 53 x 65 mm) with and without ethyl nicotinate were used to investigate the influence of visual and olfactory stimuli on the attraction of New Zealand flower thrips, (Thrips obscuratus) in a stonefruit orchard block and adjacent grass field. Greater numbers of thrips were caught in traps in the orchard compared to those in the grass field, and baited traps showed a 2-3 fold increase in thrips catch compared to unbaited traps in both locations. In both the orchard and grass field, the number of thrips caught on unbaited traps initially increased with trap size. There was no consistent relationship between catch and trap size with baited traps, except that the largest size caught the least number of thrips. On a daily basis, the number of thrips caught on traps was highly variable. The number of thrips caught on unbaited traps in both habitats increased to a peak at a maximum temperature of 6°C above the flight threshold temperature, and there was no consistent relationship between wind run and trap catch. The number of thrips caught in baited traps decreased with increasing wind run in both habitats. The implications of the above results to pest management are discussed.