SCREENING FOR SEED BORNE PATHOGENS AND FIELD DISEASES OF SOME SELECTED EXOTIC VEGETABLES IN BANGLADESH

Abstract

An experiment was conducted at Horticulture Farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during the period from October 2013 to March 2014 to study on screening of seed borne pathogens and field diseases of some selected exotic vegetables in Bangladesh. Five most popular exotic vegetables were taken for this experiment namely broccoli, Chinese cabbage, capsicum, squash and lettuce and three most cultivated varieties were used for each varieties. In seed health test, Aspergillus niger, A. flavus, Chaetomium sp. were found in broccoli. Whereas, in Chinese cabbage, capsicum and squash, A. niger and A. flavus were observed. In lettuce seed, Bipolaris sp., Chaetomium sp. and Curvularia sp. were identified. In seed bed, Alternaria leaf spot was found in broccoli and Chinese cabbage seedlings. Whereas, damping off was observed in lettuce seedlings. Besides this, powdery mildew was found in squash and mosaic disease was observed in capsicum and squash seed bed. In field condition, disease incidence and severity were recorded at three different times during growing seasons. Alternaria leaf spot (Alternaria spp.) was found in broccoli, Chinese cabbage and lettuce and the highest incidence and severity of alternaria leaf spot was recorded in Premium Crop variety of broccoli (19 and 8%). In Chinese cabbage, the highest incidence and severity of alternaria leaf spot was found in Big King (24 and 6.67%) and in case of lettuce, the highest incidence and severity of alternaria leaf spot was observed in Green Wave variety (13.67 and 4%). Mosaic (CMV) disease was observed in capsicum and squash and in capsicum the highest mosaic incidence was recorded in Capsicum First 104 (36.33%) and in squash the highest incidence of mosaic disease was observed in Hybrid Squash (28.33%). In case of powdery mildew (Oidium sp.) the highest disease incidence was found in Squash F 1 Barbuda (42.33%). In capsicum for leaf curl (YLCV) disease the highest disease incidence was observed in Sweet pepper (31.67%). The yield was showed significant variation among the varieties. In case of all diseases, it was observed that disease incidence and severity was gradually increased with the age of the plant and minimum incidence and severity gave the maximum yield.