Efficacy of cyclobutrifluram to control charcoal rot on soybean in northwestern Argentina

REZNIKOV, S.; COSTA, A.; BLECKWEDEL, J.; 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. 478. Charcoal rot of soybean, caused by Macrophomina phaseolina (Mp), is an economically important disease that affects roots and lower stems worldwide, especially when warm and dry conditions prevail during the growth cycle. The objective of this study was to evaluate in the field the efficacy of different seed treatments to control Mp on soybean in Tucumán, Argentina. The trial was conducted during the 2019/2020 crop season and included artificial inoculation of the pathogen to the soil at planting time (10 g of rice colonized with Mp per meter of row). Seven treatments were arranged in a randomized complete block design with four replications. Plots consisted of four 3-m rows, spaced 0.5 m apart (6 m2). Within the chemical seed treatments, three doses of Syngenta´s new molecule cyclobutrifluram (20, 40 and 80 mL of Victrato® 50 FS/100 kg of seed) were included in mixtures with 100 mL/100 kg of seed of Apron® Maxx RFC (2.5 g fludioxonil + 3.75 g metalaxil-M). Two chemical control treatments, Apron® Maxx RFC (100 mL/100 kg of seed) and Apron® Maxx Advanced (100 mL/100 kg of seed), were also included, along with a non-seed treatment (NST) control and a non-seed treatment Mp inoculated control (NST-Mp). The chemical treatments significantly increased plant emergence at 14, 21 and 28 days after planting compared to the NST-Mp control. Also, the chemical seed treatments resulted in higher canopy percent values than the NST-Mp control. The NST-Mp control presented 2.1 of charcoal rot severity whereas the chemical seed treatments presented values between 1.2 and 1.5 (Paris scale 1 to 5). The colony-forming units per gram were 11,100 in the NST-Mp control and ranged from 700 to 6,150 in the chemical seed treatments. These results indicate that the new molecule cyclobutrifluram, recommended against nematodes and Fusarium spp., has also the potential to control charcoal rot of soybean when used as a seed treatment.