Trichoderma and Bacillus on Faba-Bean Growth and Yield Under Soil-Borne Disease Pressure

Faba‑bean (Vicia faba L.) production serves human consumption and is critical for food security; however, yields can become exceptionally low due to soil‑borne diseases, poor fertility and adverse climatic factors. This study evaluated the effect of seed inoculation with the fungus Trichoderma spp., the bacterium Bacillus subtilis, and their dual‑consortium on disease suppression and yield improvement in faba‑bean under Bolivian Andean Altiplano conditions. A randomized complete‑block design with four treatments (Trichoderma alone, B. subtilis alone, consortium of both, uninoculated control) was employed. At the start of the trial, rice‑trap monitoring identified three major soil pathogens (Phytophthora spp., Fusarium spp., Rhizoctonia spp.). At crop maturity, only the consortium treatment resulted in the consistent detection of Trichoderma + B. subtilis, along with suppression of Phytophthora. The consortium treatment maximised pods per plant (21 pods), seeds per pod (3), root weight (≈ 68 g) and stems per plant (8), achieving a total pod yield of 29.25 t ha-1. These results demonstrate that the Trichoderma-B. subtilis consortium is a viable and sustainable technological alternative for increasing faba‑bean productivity under the challenging soil and climatic conditions of the Bolivian highlands. Future work should quantify microbial population dynamics, elucidate mechanisms of action and evaluate performance across varieties and management systems.