Bacterial Leaf Blight (BLB) Disease Incidence and Severity in Basmati and Non-Basmati Rice Growing Areas of Punjab, Pakistan

Hafiz M I Arshad,Junaid A Khan,Shahbaz T Sahi,Kamran Saleem,Syed S Alam

doi:10.33687/phytopath.009.03.3417

Abstract

Bacterial leaf blight (BLB) is one of the most damaging diseases of rice in Asia and annually incurring significant yield loss to rice production in Pakistan. Management of disease required the information of BLB incidence and severity in basmati and non-basmati rice areas. The current study presented the observation of BLB disease incidence and severity in 19 major rice growing districts of Punjab. In this study, 9 Basmati growing and 10 non-basmati rice growing districts were surveyed from September to October in 2009, 2010, 2012, and 2013. Rice fields near to roadside, research stations and adjoining farmer fields were preferred for the survey. Each halt was after 10 km on the route depending upon the crop intensity. The general appearance of the field was observed for the absence or presence of BLB disease symptoms. The incidence of BLB was recorded as a percentage of plants infected in a field on a visual basis. For each field, 4 plants were observed at 5 points/hill along the diagonal transect for disease symptoms. The data of severity was recorded as the percentage of leaf area infected out of the total leaf area. Among the districts with basmati rice, the mean incidence of BLB was maximum in Gujranwala, Sheikhupura and Hafizabad followed by Mandi Bahauddin and Gujrat. A similar pattern of disease severity was observed in the basmati rice belt with maximum BLB mean severity in Gujranwala, Sheikhupura and Hafizabad having most of the field with a severity scale of 9. Overall, the disease trend showed that both the incidence and the severity were higher in 2010, 2012 and 2013 in the basmati rice belt. The ten districts, comprising of mostly non-basmati rice varieties showed relatively less BLB incidence and severity compared to basmati rice districts. The maximum mean incidence of 20-25% was observed in Faisalabad, Chiniot and Sahiwal in at least one year of the rice season. None of the field with BLB disease symptoms was observed in districts Okara, Khanewal and Bahawalpur during the 2012 and 2013 rice season. Maximum disease severity of mean value 3 was observed in Sahiwal during 2009 while the rest of the districts showed less than 2 mean severity during all rice growing season. Overall, in non-basmati rice districts, no specific trend of disease incidence and severity was apparent, however, the disease was present in very low magnitude or absent during the surveyed years. The information from this study is helpful in the selection of variety for basmati and non-basmati districts of Punjab and the adoption of appropriate disease management strategies.

Highlights

Rice (Oryza sativa L.) is the most important food crop of the developing world and the staple food of more than half of the world's population
The current study presented the observation of Bacterial leaf blight (BLB) disease incidence and severity in 19 major rice growing districts of Punjab
The incidence of BLB disease was maximum in Gujranwala, Sheikhupura and Hafizabad with the range of 0-100% followed by Mandi Bahauddin (Table 1)

Summary

Introduction

Rice (Oryza sativa L.) is the most important food crop of the developing world and the staple food of more than half of the world's population. Yield loss of 10-20% are common and have been as high as 74%, depending upon location, season, weather, growth stage of the crop and cultivar (Mew et al, 1993; Ou, 1985). There may be 50% yield reduction depending on the stage of the crop, degree of cultivar susceptibility and to a great extent, the conduciveness of the environment in which disease occurs (Ou, 1985). Monitoring of disease in farmer field as well as at research stations or farms elucidated the appearance of new races; new varieties and fungicide opt by the farmer In this regard, the present survey was conducted during 2009, 2010, 2012 and 2013 for monitoring the BLB disease prevalence, incidence and severity in 19 major rice growing districts of Punjab province. Disease samples were collected for isolation and characterization of the pathogen

Methods

Results

Conclusion