Previous experiments indicated compatible mixtures of plant-growth promoting rhizobacteria(PGPR) strains protected plants against multiple diseases during both the rainy and winter seasons. Those results lead tothe aims of this research study as following: 1) to conduct on farm investigations the consistency of PGPR-mediated protection against indigenous tropical diseases., 2) to study grower's knowledge and awarness for using PGPR as an integrated disease management, and 3) to investigate early plant defense mechanisms involved with disease resistance. Two consecutive years were studied in grower's fields. Inthe first study year, experiments were conducted in two locations in Bungphra District, Muang, Phitsanulok.The specific hosts tested were cucumber, pepper, and tomato. In the second year, experiments were performed in one location in Tapho District and two locations in Watprig District, Muang, Phitsanulok. Only two specific hosts, pepper and cucumber, were tested. The results from both locations in the first year study indicated that most cucumber and tomato treated with PGPR mixtures (Bacillus amyloliquefaciens strain IN937a + B.pumilis strain IN937b) showed significant reductions(P?0.05) of mosaic disease and yellow leaf curl disease compared to nonbacterized control. Additionally, PGPR mixutures also showed significant suppression against pepper mosaic disease in both locations at least one season. In the second year study, PGPR mixtures significantly suppressed downy mildew disease in cucumber at least two locations and most other indigenous (mosaic, bacterial wilt,and southern blight) on long cayenne pepper in all locations throughout the seasons compared to those in nonbacterized control. Yield enhancement by PGPR mixtures was also observed. For the second objective, a one-day lecture/discussion and a PGPR fild demonstration was conducted at Naresuan University for growers who were interested in disease management and biological control measures. Farmer's knowledge and awareness were examined immediately before and after lecture/discussion and were follow-uped with the same group until 6 months after lecture/discussion. The results indicated that the intervention significantly affected farmers' knowledge. most knowledge persisted to six months. However, the intervention could not create a significant difference on farmers' awareness, except a monor improvement in the awareness of pesticide harm. For early defense mechanism involved with disease resistance, it was found that total peroxidase activity and total superoxide dismutase in plants from all 4 pathosystems; including pepper/Sclerotium roifsii, tomato/S. roifsii, tomato/Ralstonia solanacearum, and pepper/Colletotrichum gloeosporioides, rapidly increased and had significantly greater activity than plants in non-bacterized challenge control following pathogen infection. In conclusion, compatible PGPR mixtures (IN937a+IN937b) provided broad disease suppression against several indigenous tropical diseases at different locations. Additionally, plants induced by PGPR mixtures (IN937a+b) of all 4 pathosystems at least increased similar early plant defense mechanisms which are peroxidase and superoxide dismutase Moreover, a one-day lecture/discussion and a PGPR field demonstration could increase knowledge of growers, but the intervention should be practiced several times to improve grower's awareness of using PGPR as an integrated method for vegetable disease management.