TOLERANCE OF TEA CLONES AGAINST THE RED SPIDER MITE (OLIGONYCHUS COFFEAE) IN PREVAILING WEATHER PARAMETERS

ABSTRACT: The Oligonychus coffeae (Acari: Tetranychidae), known as tea red spider mite, is one of the major pests of commercial tea (Camellia sinensis (L.) O. Kuntze) plantation in the world. The aim of this study was to find out the tolerance of seven tea clones (BT1, BT2, BT8, BT19, BT20, BT21 and TV1) against the red spider mite and to know the influence of temperature, rainfall and relative humidity on red spider mite at Sylhet Agricultural University campus, Sylhet, Bangladesh during November 2021 to July 2022. The leaf infestation ranged 6.2% to 22.1% where the highest leaf infestation (22.1%) was recorded in BT2 clone while the lowest leaf infestation was 6.2% in BT21 followed by BT19 (7.8%). Similarly, the highest chlorophyll reduction (51.1%) was recorded in BT2 while the lowest reduction was in BT21 (21.8%) followed by BT1 (26.9%) and BT8 (27.5%). The results clearly indicated that the clones BT19 and BT21 are higher tolerant against the red spider mite while BT2 clone is the most vulnerable to this pest. No remarkable influence of rainfall and relative humidity on the population dynamics of red spider mite and percent leaf infestation was noticed, but temperature tended to foster the leaf infestation, abundance of protonymphs, deutonymphs and adults of the tea red spider mite. 

Keywords: Protonymphs, deutonymphs, adults, temperature, rainfall, humidity.