Population Densities and Distributions of the Western Flower Thrips (Thysanoptera: Thripidae) and its Predatory Bug, Orius niger (Hemiptera: Anthocoridae), in Strawberry

Population fluctuations of western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and its predatory bugs, Orius spp. (Hemiptera: Anthocoridae) as well as their distributions characteristics in strawberry in Adana province, Turkey were studied in 2007-2008. Populations of thrips and their predators were monitored by sampling of flowers and fruiting parts. F. occidentalis was the main thrips species and Orius niger (Wolff) was the most prevailing predatory bug of the thrips. Predators and thrips species were found mainly in the flowers, with few numbers of thrips on the fruits. WFT and O. niger significantly and regularly distributed over the fruiting parts (P<0.05). Thrips and Orius peaked in the flowers in mid-or late-May, where plants had low numbers of flowers. Numbers of Orius spp. significantly related to numbers of adult or larval thrips in the flowers (P<0.05). Numbers of WFT in flowers were much greater at the presence of low population density of Orius in 2008. While the lowest Orius spp.: thrips ratio in flowers was 1:319 and highest was 1:24 in 2007, the lowest predator: prey ratio was 1:2571 and the highest was 1:233 in 2008. WFT appeared to be not economically important pest even the highest density level of thrips with 24 individuals per flower and with 2 larvae per fruit caused damage of slight discolorations to the flowers and slight scarring to the unripe or ripe fruits in late-May in 2008. This study suggests that the O. niger could be a potential candidate for biological control of thrips in strawberry in the Mediterranean region of Turkey. c 2011 Friends Science Publishers