INCIDENCE AND SEVERITY OF RED RUST (Cephaleuros parasiticus karst.) DISEASE IN TEA UNDER DIFFERENT TOPOGRAPHIES OF SOME SELECTED TEA ESTATES AT SYLHET REGION

Abstract

The present study was conducted during April 2013 to July 2013 at different locations with a view to observing incidence and severity of red rust disease in tea under different topographic positions. The surveyed areas included in this study were BTRI farm, Gazipur tea estate, Lackatoorah tea estate, Marina tea estate, Malnichora tea estate, Chundeeche Tea Estate, Burjan Tea estate, Bejoya tea estate, Baraoora (Finlay) tea estate and Moomin cherra tea estate of Sylhet region where three different topographic positions viz. flat, hellock and tillah were considered for data collection on red rust disease incidence of tea. Fifty tea bushes/plants were randomly selected for data collection as much population of tea bushes occupied in each sample. From each location, three samples were taken randomly in each topographic position of tillah, flat and hellock. Variation in relation to incidence and severity of red rust disease of tea were observed in different locations and topographic positions. Under tillah condition, the highest disease incidence (67.33%) and severity (23.20%) were estimated from Lackatoorah tea estate while these were the lowest (25.33% and 8.25%, respectively) was related from Malnicherra tea estate. Under flat condition the highest disease incidence (84.00%) and severity (40.00%) was found in BTRI farm closely followed by Marina tea estate and Chundeeche Tea Estate. The highest disease incidence (80.67%) and severity (34.13%) were recorded from the crop grown under hellock condition at BTRI while the lowest (36.67%) disease incidence was observed at Baraoora tea estate. Tea grown under hellock position of Burjan Tea estate showed the lowest red rust severity (13.33%). The results indicated that there was a negative correlation between elevation and disease incidence. Red rust disease incidence was decreased with an increasing elevation of the plantation. The highest disease incidence and severity of red rust were estimated from the tea grown under flat condition which was followed by hellock and tillah conditions. The average disease incidence of 70%, 59.00% and 49.00% were recorded from flat, hellock and tillah region respectively.