Nutrient Omission and Aphelenchoides besseyi Interaction in Soybean Plants

Abstract

ABSTRACT The phytonematode Aphelenchoides besseyi gained prominence in Brazil following its identification as the etiological agent of leaf and green stem retention in soybean plants. Thus, this study evaluated the effects of nutrient omission on the phytotechnical characteristics of soybean in the presence and absence of A. besseyi. The experiments were carried out in a completely randomized 2 × 11 factorial arrangement, with 11 treatments: control (no nutrients), complete nutrition, and individual -N, -P, -K, -S, -B, -Cu, -Fe, -Mn, and -Zn omission were applied to inoculated and uninoculated plants, and six replicates. The presence of A. besseyi adversely affected the growth characteristics, except when -P, -S, -B, -Mn, and -Zn were omitted. The nematode reduced the root length in treatments omitting -K, -S, -B, -Cu, -Fe, -Mn, and -Zn and root fresh weight when -N, -P, -K, and -Cu were omitted. In the absence of the pathogen, N assimilation did not differ significantly between the treatments; however, it was negatively influenced by the presence of the pathogen in the control and complete nutrition treatment. The leaf area index values were the lowest in inoculated plants with no nutrition, with complete nutrition, and with -N, -P, -K, and -Cu omissions. The micro- and macronutrients concentration and the shoot dry weight (SDW) were high in the presence of the nematode, except in treatments where -N, -S, and -Mn were omitted. The nutritional status does not affect infection by the nematode A. besseyi, but the application of nutrients is necessary for soybean development.