INTERA??O ENTRE INDUTOR DE RESISTêNCIA E MICRONUTRIENTES NO CONTROLE DO NEMATOIDE DAS LES?ES E NO DESENVOLVIMENTO DE PLANTAS DE SOJA

摘要

Root lesion nematodes limit the productivity of several crops of economic importance, requiring alternatives for their management. Resistance inducers activate enzymes involved in defense mechanisms and micronutrients can influence this process by acting as enzymatic cofactors. Thus, the objective of this study was to evaluate the effect of foliar application of a commercial organomineral fertilizer and its association or not with zinc (Zn) and manganese (Mn) micronutrients on the Pratylenchus brachyurus suppression and soybean plant development under greenhouse conditions. Shoots of soybean were treated 10 days after germination and inoculated with 5000 nematodes/plant five days after the treatments, using untreated plants as controls. Treatments consisted of a commercial product based on phosphorylated mannanoligosaccharide derived from the cell wall of Saccharomyces cerevisiae (here coded as MOS), Zn, Mn, MOS Zn, MOS Mn or MOS Zn Mn. At sixty days after establishment of treatments, the plants were collected and evaluated for vegetative analysis, nematological analysis and nutrient contents. The work was repeated at different times: experiment 1 from November 2016 to January 2017 and experiment 2 from October to November 2017. All treatments were efficient in controlling P. brachyurus in at least one of the evaluated nematological parameters, compared to the control. However, only the plant spraying with MOS Zn results in significative reduction of the total number of nematodes and the number of P. brachyurus nematodes per gram of soybean root in both experiments. In addition, spraying of plants with Mn increased shoot dry weight and all treatments resulted in higher concentrations of copper, Zn and Mn in soybeans leaves compared to control.