MANEJO NUTRICIONAL, QUÍMICO E BIOLÓGICO DE HETERODERA GLYCINES E PRATYLENCHUS BRACHYURUS NA CULTURA DA SOJA

Abstract

Soybean (*Glycine max* L.) is a major crop in Brazilian agribusiness, frequently affected by plant-parasitic nematodes—notably *Heterodera glycines* and *Pratylenchus brachyurus*—which cause significant yield losses. In this context, this study aimed to evaluate the effect of different rates of boron (B) and copper (Cu) on the population dynamics of these nematodes, as well as on soybean yield and economic viability. The experiment was conducted in Urutaí, Goiás (GO), using a randomized complete block design with 18 treatments and four replications. Treatments included soil-applied B, foliar-applied Cu, and chemical and biological standards, alongside an untreated control. Nematode assessments were performed at 30 and 60 days after emergence (DAE). Results indicated numerical variations in *H. glycines* and *P. brachyurus* populations in treatments with higher boron rates, whether applied alone or in combination with copper. Additionally, numerical variations were observed in the number of non-viable cysts in the soil in treatments combining the two micronutrients. However, the differences observed among treatments were not statistically significant according to Tukey's test (p < 0.05). Crop yield was limited by severe water deficit conditions lasting approximately 40 days of the growing season, compounded by potential phytotoxicity from the higher micronutrient rates, resulting in low yields across all experimental plots. Thus, the results suggest that nutritional management with boron and copper may be associated with numerical variations in nematode population dynamics, although no control effect was demonstrated under the conditions of this study. Further studies are recommended—preferably in controlled environments and under diverse field conditions—to evaluate intermediate rates and investigate the potential relationship between plant nutritional status, nematode population dynamics, and crop physiological stability.