STUDY ON NEW BIOPESTICIDES VAAS-AT1 AND VAAS - AT2 TO CONTROL THE PEPPER ROOT ROT AND ROOT - KNOT NEMATODE DISEASE AND COFFEE YELLOW LEAF AND ROOT ROT DISEASE IN VIETNAM

Abstract

This study aimed at evaluating the efficacy of biopesticides containing nematophagous fungi and antagonistic microorganisms, named VAAS-AT1 and VAAS-AT2, for controllingplant-parasitic nematodes and pathogenic fungi causing root rot and root-knot nematode disease complex in black pepper plants and yellow leaf and root rot diseases in coffee plants in Vietnam. A series of experiments were conducted in greenhouses, small-scale experiments, and field demonstrations. The results showed that both biopesticides effectively reduced the population of plant-parasitic nematodes and pathogenic fungi in the soils growing with black pepper and coffee plants. In greenhouse conditions, VAAS-AT1 demonstrated an efficacy of 83.3% against Phytophthoracapsici, 79.5% against Fusarium solani, 60.6% against Rhizoctonia solani, and 77.8% against plant-parasitic nematodes after 3 months of treatment. In small-scale field trials, VAAS-AT1 achieved efficacies ranging from 81.3 to 83.5% against Phytophthora spp., 82.3 to 83.7% against Fusarium spp., and 80.3 to 81.9% against plant-parasitic nematodes after 9 months of treatment. In field demonstrations, the efficacy of VAAS-AT1 reached up to 79.3% in Dak Lak province and 77.6% in Gia Lai province against the pepper root rot disease after 9 months of treatment. VAAS-AT2 exhibited its efficacy in greenhouse conditions by reducing the population of plant-parasitic nematodes by 69.82% and F. oxysporum by 76.44% after 3 months of treatments. In small-scale field experiments, VAAS-AT2 achieved efficacies of 76.16 to 78.12% against plant-parasitic nematode and 78.04 to 79.26% against Fusarium spp. after 9 months of treatment. In the field demonstrations, the efficacy of VAAS-AT2 against yellow leaf disease in coffee plants reached 72.73 to 79.3% after 9 months of treatment in Dak Lak and Gia Lai provinces, respectively. Furthermore, the economic benefits of using VAAS-AT1 and VAAS-AT2 were substantial, with income increases of 17.89 to 25.80% for farmers and a benefit over control ranging from 5.260 to 22.500 million VND/ha. These findings demonstrate the promise of VAAS-AT1 and VAAS-AT2 as effective biopesticides for enhancing crop health and income for farmers in Vietnam.