Biological control of charcoal rot of soybean in Tucumán, Argentina

BLECKWEDEL, J.; REZNIKOV, S.; GONZALEZ, V.; PLOPER, L.D.

Viena

Congreso; World Soybean Research Conference XI (WSRC XI); 2023

Donau Soja Association (Vienna, Austria) - Institute of Field and Vegetable Crops (Novi Sad, Serbia)

Book of Abstracts “Soybean Research for Sustainable Development. p. 457. Macrophomina phaseolina is the causal agent of charcoal rot on soybean, an economically serious and potentially destructive disease. One of the strategies to manage this pathogen is the use of chemical fungicides as seed treatment. However, chemical control sometimes has limited effects on disease severity and may pose a threat to the environment, so the use of biological products could be an alternative for charcoal rot management. Different species of Trichoderma have been recognized as potential biocontrol agents of plant diseases. The objective of this research was to isolate and characterize native Trichoderma spp. from different commercial fields in northwestern Argentina and study their antagonistic effect against M. phaseolina on soybean. Isolations were performed from soil samples followed by cultural and microbiological characterization of the different native Trichoderma spp. isolated. Then, the antagonist effect of these isolates against M. phaseolina was studied in vitro (dual-culture technique), under greenhouse conditions, and finally under field conditions with pathogen artificial inoculations at planting time during two soybean crop seasons (2019/2020 and 2020/2021). The results demonstrated that isolate Tr009 had a biocontrol effect against M. phaseolina on soybean. This control was evidenced in vitro by competition for the substrate (percent inhibition of radial growth= 71.3%) and mycoparasitism, as well as by a higher emergency of plants compared to the M. phaseolina inoculated control, both under controlled and field conditions. Also, under field conditions, treatments that included Trichoderma presented lower disease severity and colony-forming unit index values than the pathogen inoculated control. Moreover, Tr009 improved weight and length of soybean plants under greenhouse conditions. By means of molecular methods, isolate Tr009 was identified as Trichoderma koningiopsis. These results indicate that this biological tool can be used against M. phaseolina and thus favor a sustainable management of soybean charcoal rot. Further studies should be carried out to evaluate the effects of this biological agent against other economic important crop pathogens.