Plant disease monitoring and disease diagnosis, 1994/95

Plant disease monitoring by Lumle Agricultural Research Centre (LARC) through its network of off-station research sites (OSR), outreach research sites (OR) and also in farmers fields is conducted regularly to understand disease dynamics and their relative economic importance. A vertical transect from an altitude of 400m (Yampaphat, Bhotewodar and Taranagar) to 2200m (Lopre) was used to observe the disease intensity, severity and crop loss in different cropping patterns, different agroecological zones and different soil fertility conditions. The most damaging disease identifed in rice was neck blast (Pyricularia oryzae). Footrot of rice (Fusarium monilliforme) was also observed to be increasingly important in Baglung, Parbat and Myagdi district specially in the low (800) and mid hill (1300m). Brown spot of rice was found in the seedling crop stage in low fertility areas and leaf blast also occurred in locally infesting seedlings of Mansuli variety. Leaf rust of wheat was found severe in Taranagar of Gorkha and Rishing Patan of Tanahun district. Some recommended varieties like NL 297 and Nepal 251 were found severely attacked by leaf rust, however, this disease was very less in the promising variety NL 683 and Bl 1496. Severe infestation of the leaf curl virus disease occurred in tomato growing areas of Dhanubase, Yampaphant and Rishing Patan. A total of eighty nine diseased samples of cereal, vegetable and fruit crops were studied and identified at LARC Plant Protection Laboratory. There were eleven bacterial diseases and eight viral diseases. Among the most common bacterial disease was bacterial wilt of tomato (Pseudomonas solanacearum). The disease bacterial blight of soyabean (Pseudomonas syringae), freckle (Phllostictina musarum) and anthracnose (Gleosporium musarum) disease of banana and sheath rot (Pseudomonas sp.) disease of wheat were identified in the laboratory. Several virus samples from tomato were preserved for identification in cellulose membranae and were sent abroad for identification. The virus samples of tomato were identified to be Tomato Yellow Leaf Curl Virus (TYLCV virus) transmitted by white fly