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In Bangladesh, Fusarium proliferatum is a prevalent pathogen of maize plants that poses a significant threat to human health and livestock by producing carcinogenic fumonisin. However, the use of the Bacillus species, which can colonize the infected plant parts, has been practiced globally to mitigate fumonisin contamination in maize. In this study, B. subtilis MMM1, a native isolate from the maize rhizosphere, was found to be the most effective antagonist against F. proliferatum, which reduced their mycelial growth and total fumonisin accumulation by 85.31% and 85.12%, respectively, over control through a fivefold reduction in fungal population (1.1 × 104 CFU/g maize grain) in vitro. Furthermore, out of the five bacilli used in this study, B. subtilis MMM1 was able to increase the root and, shoot length, and the vigor index of maize seedlings, by colonizing the fresh roots at 82 × 106 CFU/g root tissue. This suggests that B. subtilis MMM1 might be put forth both as a biocontrol agent and a plant growth promoter in Bangladesh to combat F. proliferatum. Nevertheless, evaluation of its efficacy in reducing fumonisin contamination in maize should be investigated under field conditions.

Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae is a destructive disease of rice causing significant yield losses. Surveys were conducted to know the influence of weather parameters on epidemic development of BB in the thirty agroecological zones of Bangladesh. The maximum (55.11%) bacterial blight incidence and severity were recorded Mymensingh division (AEZs 8 and 9) while the minimum (3.25%) incidence was observed in Barishal division (AEZ 13) in both rainfed and irrigated seasons. In rainfed conditions, the maximum BB incidence and severity were recorded in hybrid varieties Aloron from Netrokona (AEZ 9) and the minimum incidence was observed in the local variety Sughondi from Jalhokhati (AEZ 13). On the other hand, in irrigated conditions, the highest BB incidence was recorded in the hybrid variety Hera-2 from Netrokona (AEZ 9) and the lowest incidence was observed in the local variety from Hobiganj (AEZ 20, 21, 22). Swarna, Puja, BRRIdhan28, BRRIdhan29, and BRRIdhan49 showed intermediate levels of infection, while hybrid Hera-2, Arize TejGold, Partex, Agrodhan, Aloron, ACI-2, and Dhani Gold showed higher level of infection (susceptibility) to BB. The data analysis on BB incidence with the weather parameters of rice growing seasons from 2015 to 2017 revealed that the rainfall distribution varied greatly within rice growing seasons over the years. The results indicated that weather parameters, viz. temperature (25-34°C), relative humidity (70-84%), and rainfall (>200mm), largely affected the prevalence, incidence and severity of BB. The correlation studies revealed that, among the climate variables, minimum temperature exhibits a negative correlation. However, rainfall, maximum temperature, morning relative humidity and evening relative humidity were found positively correlated, while wind velocity imparted a significant positive correlation with BB infection. The regional outbreak of BB indicated a considerable yield loss of rice and give rise a threat for food security of the country.

Bacterial blight (BB) caused by X. oryzae pv. oryzae is a destructive disease of rice and causes 30-50% losses to rice depending on the outbreak. Development BB resistant rice varieties have long been considered as one of the most effective approach to control the disease. However, the durability of host resistance is breaking down due to the change of pathotypes of X. oryzae pv. oryzae globally. Pathotypic analyses of 239 X. oryzae pv. oryzae Bangladeshi isolates on Near Isogenic Lines (NILs) containing resistance (R) gene (s) revealed the existence of eight pathotypes of X. oryzae pv. oryzae. Among eight pathotypes, pathotypes IV and V were considered as major comprising  maximum number of isolates, (30.13% and 23.01%, respectively), whereas pathotype VIII considered as minor consisting only 2.51% of total isolates. Pathotype, I showed highest virulence or aggressiveness compatible with all NILs, whereas pathotype VIII exhibited lowest virulence to these NILs. Bacterial blight resistant genes viz. Xa1 (75.00%), Xa11 (62.50%) and Xa21 (50.00%) showed resistance to most of the pathotypes while Xa4 performed worst as compared to all others R-genes. In pyramid lines, IRBBB63 (Xa5+Xa7+Xa13) and IRBB57 (Xa5+Xa7 +Xa21) showed resistance reaction and IRBB61 (Xa4+Xa5+Xa7), IRBB60 (Xa4+Xa5+Xa13+Xa21), IRBB54 (Xa5+Xa21), and IRBB53 (Xa4+Xa21) showed susceptible reaction to X. oryzae pv. oryzae pathotypes. These results collectively indicated the deployment of Xa1, Xa11, Xa4, Xa5, Xa7, Xa13 and Xa21 either alone or in combination against BB would be a best choice for the development of BB resistant rice varieties in Bangladesh.