International Journal of Advancements in Research & Technology, Volume 2, Issue 9, September-2013 96 ISSN 2278-7763 Copyright © 2013 SciResPub. IJOART Effect of dates of sowing on incidence and severity of Mungbean Yellow Mosaic Virus and Cercospora Leaf spot of mungbean M. Harunor Rashid 1 , M. Sazzadul Aktar 2 , Ismail Hossain 2 , M. Mahbubur Rahmam 1 , M. Rashed Hasnat 3 and Nair RM 4 1 Regional Agricultural Research Station, Bangladesh Agricultural Research Institute, Rahmatpur, Barisal- 8211, Bangladesh 2 Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, Bangladesh 3 Instructor, Agricultural Training Institute, Faridpur, Bangladesh 4 AVRDC, ICRISAT Campus, Hyderabad, India Corresponding author : SSO, Plant Pathology: E-mail: md_harunor_rashid@yahoo.com ABSTRACT An experiment was conducted at Regional Pulses Research Station, BARI, Madaripur during 2011 in order to study the effect of dates of sowing on the incidence and severity of diseases and yield of Mungbean. Results revealed that the disease incidence of Mungbean Yellow Mosaic Virus (MYMV) of six varieties/lines, BMXK2 03000, BMXK2 03005-4 and BARImung-6 showed highly resistance (HR), resistant (R) and resistant to moderately resistant reaction, at the sowing time of January 15, February 01- 15 and April 01 respectively. In, sowing BMXK2 03005-4 and BARImung-6 showed moderately resistance (MR). But in MYMV disease severity BMXK2 03005-4 and BARImung-6 showed 1 scoring scale starting from January 15 to March 15 sowing. In April 01, sowing disease severity of BMXK2 03005-4 and BARImung-6 showed 3 scoring scale. In case of CLS, BMXK2 03005-4 and BARImung-6 showed 1 scoring scale from January 15 to February 01 sowing. February 15 to April 01, sowing showed 2 scoring scale. The yield performance ranged from 681.30 kg/ha to 2131.00 kg/ha while the highest (2131.00 kg/ha) yield was found in S 4 XE 4 i.e. March 01, 2011 sowing with BMXK 2 -030005-4. The lowest (681.3 kg/ha) yield was found in S 6 ×E 3 i.e. April 01, 2011 sowing with BMXK 2 -03000 line. A strong correlation was obtained the incidence of MYMV and yield. It means that with the increase of incidence of MYMV (%), yield of mungbean decreased. The correlation coefficient (r) was – 0.797** and the contribution of the regression (R 2 = 0.6355) indicate that 63.55% yield to mungbean would be affected by MYMV infection. Key word: Vigna radiata L. wilczek, sowing date, Mungbean Yellow Mosaic Virus, Cercospora leaf spot (CLS) and yield 1. INTRODUCTION Mungbean (Vigna radiata L. wilczek) is one of the most important pulse crops in Bangladesh. The agro- ecological condition of this country is favorable for its cultivation. It can be grown in late rabi, kharif-1 and kharif-2. It is important pulse crops having global economic importance as a dietary ingredient of the stable food. It contains 55% carbohydrate, 26% protein, 10% moisture and 3% vitamins. It is also capable of fixing atmospheric nitrogen (222 kg/ha) through symbiotic relationship with Rhizobium in the root nodule of the crop. Mungbean is an important protein rich crop and occupies first position in price and second in acreage and third in production of Bangladesh “[1]” Though the agro-ecological condition of Bangladesh is favorable for mungbean cultivation, both its total area under cultivation and production, but yield of the crop is low compared to other pulses in Bangladesh ‘[2]’. There are many constraints responsible for the low yield of mungbean. Among those, diseases are considered to be the most important. A total of twenty diseases of mungbean have been recorded in Bangladesh [3]. Of which four and two diseases are major in field and stored respectively. Yellow Mosaic Disease, Cercospora leaf spot, Powdery mildew (Erysiphe polygoni) and Leaf rot (Sclerotinia sclerotiorum) are the four major diseases found in the field. Among the diseases Cercospora leaf spot (Cercospora cruenta Sacc.) and the yellow mosaic incited by yellow mosaic virus [4] are the most important and damaging diseases of mungbean that incurred significant yield reductions every year in Bangladesh [5]. The early infected plants showed more severe symptom of yellow mosaic than that of the late infected plants [6]. The incidence and severity of IJOART