Effect of Climate Change Resilience Strategies on Common Bacterial Blight of Common Bean (Phaseolus vulgaris L.) in Semi-arid Agro-ecology of Eastern Ethiopia

Abstract

Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli is the most important biotic production constraint to common bean in eastern Ethiopia. Climate change could have an impact on the disease epidemiology by influencing both common bean growth and the pathogen reproduction. The effects of climate change needs to be mitigated using climate change resilience strategies. Field experiments were conducted in the 2012 and 2013 cropping seasons at Haramaya and Babile research stations in eastern Ethiopia to assess the effects of integrating climate change resilience strategies on CBB of common bean. Gofta (G2816) and Mexican 142(11239) common bean varieties were used. Eight climate change resilience strategies used were compost application, row intercropping and furrow planting alone and in combination. Factorial combinations of two common bean varieties and eight climate change resilience strategies totally 16 treatment combinations were studied in randomized complete block design (RCBD) with three replications and repeated once. Disease severity data were recorded from 10 randomly tagged plants from four central rows per plot. Disease severity, area under disease progress curve (AUDPC) and disease progress rate were significantly different among climate change resilience strategies, between varieties, cropping seasons and locations. Disease severities, AUDPC and disease progress rate were consistently less on row intercropping + compost application + furrow planting and row intercropping + compost application compared to singly applied climate change resilience strategies and sole planting plots in both locations and seasons. The disease epidemic was relatively higher on Mexican 142 than Gofta and during 2012 than 2013 at Babile than Haramaya. Integrated climate resilience strategies reduced CBB epidemics and could be applied as a component in management of CBB in eastern Ethiopia and in areas with similar agro-ecological zones.

Vermicompost and bactericide application minimized common bacterial blight development and enhanced nodulation and agronomic performances of bean varieties in Southern Ethiopia

“…A strong and significant relationship between yield with nodules and other agronomic traits might indicate that nodulation, growth, and yield component parameters could have a positive and direct influence on GY of bean genotypes (Ahmadi & Arain, 2021; Bitew et al., 2022; Mengesha et al., 2021; Yitayih et al., 2022). In the current study, a significant and negative association of the disease severity and AUDPC with nodule and agronomic parameters as stated by Hailu and Tontosha (2021) could imply that the disease may play a detrimental role in damaging the nodulation and agronomic characteristics and estimating yield loss in common bean. This could be explained by the fact that the disease is known to disturb nutrient metabolism, reduce the rate of photosynthesis, and reduce seed weight, and thus GY in bean (Garry et al., 1998).…”

“…In line with the present study, applications of protectant chemicals every 7−14 days early in the season before symptoms decrease the establishment of bacterial diseases (Schwartz, 2004). A previous study by Hailu and Tontosha (2021) reported a 31.8% disease severity reduction over unsprayed plants due to bactericide (Kocide‐101) sprays at the 14‐day interval at HARC during 2017/2018. by decreasing bacterial pathogens on bean leaves and spreads to healthy plants (Schwartz, 2004; Wohleb & du Toit, 2011).…”

“…In the present study, the increasing number of pods and seeds, GY, and dray biomass in both varieties treated with a combination of VC and three times bactericide applications at the 7‐day interval might be associated with improvement of soil fertility, microbial activity and biomass, nutrient availability, root development, nutrient uptake, phytohormone release via VC application, and reduction of CBB establishment and development by bactericide sprays, which ultimately promote plant growth, reproductive processes, and grain production (Argaw & Mnalku, 2017; Fernández‐Luqueo et al., 2010; Hailu & Tontosha, 2021; Shanka et al., 2018). In addition, the use of VC in a substrate or as a spray drench to improve nodulation, growth, and yield in several legumes, viz.…”

“…There are various research reports suggesting that VC applications alone and in integration with organic or inorganic fertilizers enhance soil fertility, nutrient uptake, mineralization, N‐fixation, plant growth and productivity, soil physical conditions (aeration, drainage, facilitation of actions of N, P, and K exchange) and moisture retention capacity, soil microbial population and activity, and nutrient cycling (Bark & Gulati, 2009; Manivannan et al., 2009; Roy et al., 2010; Saha et al., 2008; Sharma et al., 2018) and suppress plant pests through different mechanisms (Basco et al., 2017; Baum et al., 2015; Doan et al., 2015; Edwards et al., 2004; Koul, 2008; Mohamadi et al., 2017; Nadana et al., 2020). Chemical seed treatment and foliar applications have also been considered promising options to manage the CBB of common bean across the world (Ararsa et al., 2018, 2019; Girma, 2023; Hailu & Tontosha, 2021; Harveson, 2009; Schwartz, 2004).…”

“…The condition calls for the devising and administration of effective management strategies. Disease management alternatives, including cultural practices such as plant debris management, use of pathogen-free seeds, crop rotation (Agrios, 2005), use of intercropping and varietal mixtures (Fikire, 2004;Fininsa, 2003), use of resistance varieties (Adila et al, 2021;Schwartz, 2004;Wohleb & du Toit, 2011), copper-based bactericide applications (Hailu & Tontosha, 2021;Schwartz, 2004), and integrated options (Girma, 2023;Gudero & Terefe, 2018) are recommended to minimize the damage caused by CBB. The integration of cultural practices, resistant varieties, and biocides is a costeffective and eco-friendly approach and lowers the chance of resistance development and damage levels and improves grain yield (GY) (Agrios, 2005).…”