**5. Management strategies**

Successful disease control generally relies on employing management strategies toward reducing the damage to a manageable and acceptable level. These strategies

**75**

*Sustainable Strategies for Managing Bacterial Panicle Blight in Rice*

are exclusion, genetic resistance, chemical control, biological control, and cultural practice. However, for control of the BPB disease at a given geographical area, there are few management options available currently. To effectively manage rice BPB, rice producers must start with the use of pathogen-free seeds as an exclusion measure, plant with partially resistant cultivars, apply with available chemicals or biocontrol agents, and use proper cultural practice. Integrated use of these available management strategies is the key to the effective and sustainable control of the BPB disease.

Since the BPB disease has been reported in more than 18 countries (**Table 1**) and the disease is not present in all the rice-producing countries and regions, exclusion of the BPB pathogens from a disease-free region is the most effective strategy to prevent BPB of rice. Plant quarantine is an effective measure to achieve this goal. For example, within the USA, the state of California has employed a plant material quarantine procedure to prevent the introduction of the BPB pathogens, other rice pathogens, and weed and insect pests into the state from the southern rice-producing USA. A similar plant quarantine law has been established and enforced in China to prevent the potential importation of the BPB pathogens from foreign countries since 2007 [21]. BPB is seedborne and infected seeds serve as the primary source of inoculum [1, 2, 48]. Therefore, the use of certified seeds that are free of the BPB pathogens is another effective measure to exclude the disease from a disease-free geographic area. Different molecular detection methods including PCR that have been developed to test rice seed lots [19, 48] can aid in this process. In the USA, the use of pathogen-free seeds is recommended to manage the BPB disease. However, using PCR procedure to ensure the BPB pathogens free in certified seed has not been employed. To reduce the BPB disease, it is recommended that farmers should not use the seeds harvested from the fields that are infected with BPB the previous year. Seed treatment can serve as the last resort to reduce and even eliminate the seedborne BPB pathogen populations and to control subsequent head disease to an accepted level. Rice seeds treated at 65°C of dry heat for 6 days can eradicate the BPB pathogens [26]. Seed treatment with the antibiotic bactericide oxolinic acid (Starner®) has been shown to control the bacterial pathogens in naturally and artificially infected seeds [59]. An antagonistic *Pseudomonas* spp. strain when applied onto seeds was effective to reduce the *B. glumae* populations in seed and suppress seedling rot [60]. Seed treatment with hot water at 60°C for 10 minutes is ineffective for control of the BPB disease although such seed treatment practice is effective

Considerable research efforts have been conducted globally to develop resistant cultivars as an effective and sustainable strategy for management of BPB of rice. Unfortunately, no single genes or quantitative trait loci (QTLs) for complete resistance to BPB have been found so far [13, 14]. Only several rice cultivars with partial resistance are available for commercial use. In Japan, BPB resistance breeding research efforts started as early as 1975; three partially resistant cultivars were identified through a field screening of nine cultivars and lines [62]. No resistant cultivars and breeding lines were identified in a study of screening 293 cultivars and lines using greenhouse inoculation at the flowering stage in 1983 [63, 64]. From 1985 through 2013, there were nine reported studies that screened a total of 798 cultivars and breeding lines in the field and greenhouse and identified a total of 28 cultivars and lines showing partial resistance to BPB [13, 65–73]. Most recently, Mizobuchi et al.

*DOI: http://dx.doi.org/10.5772/intechopen.84882*

to control the rice blast pathogen *M. oryzae* [61].

**5.2 Genetic resistance**

**5.1 Exclusion**

are exclusion, genetic resistance, chemical control, biological control, and cultural practice. However, for control of the BPB disease at a given geographical area, there are few management options available currently. To effectively manage rice BPB, rice producers must start with the use of pathogen-free seeds as an exclusion measure, plant with partially resistant cultivars, apply with available chemicals or biocontrol agents, and use proper cultural practice. Integrated use of these available management strategies is the key to the effective and sustainable control of the BPB disease.
