Belowground Influence of Rhizobium Inoculant and Water Hyacinth Composts on Yellow Bean Infested by Aphis fabae and Colletotrichum lindemuthianum under Field Conditions

Abstract

Rhizobium inoculant has been developed for bean production in Lake Victoria basin. Two types of compost have been developed, water hyacinth compost with cattle manure culture (H+CMC) or with effective microbes (H+EM). Influence of Rhizobium and composts on Aphis fabae and Colletotrichum lindemuthianum were investigated in the field. Rhizobium and hyacinth composts increased nodulation (×2 to 5); while Aphis fabae population increased (×2) on Rhizobium-inoculated plants with H+EM. Incidence of C. lindemuthianum was high in Rhizobium-inoculated plants. Plants that received diammonium phosphate (DAP) fertilizer had few nodules, reduced germination, slow growth and low yields. In conclusion, the water hyacinth composts contain beneficial microbes that promote root nodulation by Rhizobium, which is necessary for nitrogen fixation, while enhancing tolerance to aboveground infestations by A. fabae and C. lindemuthianum. We raise questions on our results to stimulate research, considering that bean breeding programs in Africa have mainly focused on microbial pathogens, and not insect pests.

Rhizobium-Linked Nutritional and Phytochemical Changes Under Multitrophic Functional Contexts in Sustainable Food Systems

“…Various published works have linked rhizobium infection to nutritional and phytochemical changes that affect consumers in multitrophic systems (Tables 1, 2). Nutritional suitability of host plants is therefore influenced by rhizobium infection (Naluyange et al, 2014(Naluyange et al, , 2016Karoney et al, 2020), while prevention of overexploitation by the consumers depends on the expression of such compounds in terms of host plant resistance and tolerance (Enneking and Wink, 2000;Joosten and van Veen, 2011;Goyal et al, 2012;Goyal, 2013;Karoney et al, 2020).…”

“…Organic carbon and nitrogen produced by the photosynthesis-nitrogen fixation machinery of legumes and rhizobia supports consumers at various trophic levels. Consumers are affected by compatible relationships between host plants and Rhizobium species (Dean et al, 2014;Naluyange et al, 2014Naluyange et al, , 2016Pulido et al, 2019;Karoney et al, 2020;Xu et al, 2020). Consumers are also affected by antagonisms arising from incompatible relationship between host plants and rhizobium species (Gourion et al, 2015;Clúa et al, 2018; Modi et al, 1985;Guerinot et al, 1990;Deshwal et al, 2003a Rhizobium Rioux et al, 1986;Dilworth et al, 1998;Deshwal et al, 2003a Benezech et al, 2020a).…”

“…Indirect interactions exist between Rhizobium in root nodules and consumers in the phyllosphere through host-mediated processes (Kempel et al, 2009). Rhizobium infection of leguminous roots has been linked with increased colonization of common bean leaves by the fungal pathogen Colletotrichum lindemuthianum (Naluyange et al, 2014(Naluyange et al, , 2016Karoney et al, 2020). Also, the presence of Rhizobium in leguminous roots is associated with increased abundance of arthropods such as aphids and mites (Katayama et al, 2011a,b;Dean et al, 2014;Naluyange et al, 2014Naluyange et al, , 2016.…”

Soil Maize Cultivar-related Challenges on Striga hermonthica Infested Fields in Western Kenya

“…The HCM, HEM and CM composts were applied volumetrically using containers of 150 mL per hole as per the respective treatments and mixed with soil (Naluyange et al, 2014). The water hyacinth composts therefore supplied approximately 0.9 g N, 0.02 g P, and 0.99 g N, 0.03 g P, for HEM and HCM, respectively (Naluyange et al, 2016). DAP fertilizer was applied at the rate of 2 level teaspoonfuls per planting hole (~10 g) and mixed with soil; supplying approximately 2.1 g N and 2.3 g P. One maize seed per hole was planted at a depth of ~3 cm, together with a table spoonful of S. hermonthica seed-sand mixture (approx.…”

“…HEM is fortified with Effective Microbes ™ , comprising of photosynthetic bacteria (Rhodopseudomonas palustris), lactic acid bacteria (Lactobacillus plantarum and L. casei), yeast (Saccharomyces cerevisae), molasses, and water (EM Technologies Ltd, Embu, Kenya) (Higa & Parr, 1994;Chandi, 2003). The nutrient composition of the two water hyacinth composts are outlined in Naluyange et al (2014Naluyange et al ( , 2016. Cattle manure (CM) was obtained from stocks locally composted through heaping by farmers.…”