Biology of grape thrips [ Rubiothrips vitis (Priesner) (Thysanoptera: Thripidae)] and their damage to the Sultani Cekirdeksiz (Vitis vinifera L.) vineyards of Manisa, Turkey
Abstract: The damage caused by grape thrips Rubiothrips vitis (Priesner) (Thysanoptera, Thripidae) to the Sultani Cekirdeksiz (Vitis vinifera L.) grape variety and the fluctuations in the thrips population were evaluated in the Alaşehir district of Manisa province in two untreated vineyards. The biology of R. vitis was examined under laboratory conditions in 2004 and 2006. It was described by population fluctuation, by examination of grapevine organs and by counting the number of individuals detached from the grapevine by the shaking method. The duration of each life phase (larva, prepupa, pupa, preoviposition, oviposition, and postoviposition) and the longevity of R. vitis were determined at 25 ± 1 °C, 60 ± 10% relative humidity (RH), and 16 hour of light, at an illumination of 4000 lux. R. vitis was first observed on grapevines in April a time corresponding with bud burst. Their population reached its highest level in April-May. The thrips preferred the newly emerged buds and young shoots of the grapevine. At the end of May, the thrips population decreased and continued at a low intensity until the grape harvest. R. vitis individuals were collected in the vineyard by the shaking method from the following organs: bud + young shoot (10-15 cm), bud + flower/fruit bunches, and the leaves on shoots with 5-6 leaves. The pest entered the grapevine buds, feeding and laying eggs. As the young leaves in these buds grew, it was observed that the damaged tissues tore and desiccated from the sides. The duration of the life phases in R. vitis were as follows: embryonic development 5.5 ± 0.3 days; larval stage 5.4 ± 0.4 days; prepupa stage 1.4 ± 0.11 days; and the pupa stage 2.3 ± 0.14 days. The preoviposition period was 1.7 ± 0.15 days, the oviposition period 16.9 ± 1.17 days, and the post oviposition period 5.8 ± 0.32 days. Females of R. vitis laid an average of 12.45 ± 0.81 eggs and the longevity of the female was 22.4 ± 1.92 days while that of the males was 13.15 ± 1.19 days.