Bacillus amyloliquefaciens e Trichoderma harzianum NO MANEJO DE Pratylenchus brachyurus e Helicotylenchus sp. NA CULTURA DA SOJA

Abstract

Brazil is the second largest producer in the world, accounting for about 20% of the total production. However, during its development, this culture can be adversely affected by several factors, such as nematodes. The losses caused by phytonematoids range around 12%, depending on the crop type, and can reach up to 30% in soybean production. This study aimed to evaluate the efficiency of biological control of nematodes Pratylenchus brachyurus and Helicotylenchus sp. in soybean crops, using the bacterium Bacilus amyloliquefaciens in different concentrations, associated with the fungus Trichoderma harzianum. The experiment was conducted in a Randomized Block Design (RBD), containing 7 (seven) treatments and 5 (five) replicates, distributed uniformly in plots of 18 m2 . The treatments were: control; abamectin 100 mL.100kg of seed-1 applied via seed treatment; 100 mL, 200 mL, 300 mL, 400 mLand 500 mLof B. amyloliquefaciens, respectively, with a concentration of 2.0 x 10¹¹ / mL, associated with 300 mL of Trichoderma harzianum with a concentration of 1.0 x 109 / mL, applied through a planting groove. The variables analyzed were: set and height of plants at 13 and 21 days after planting (DAP); fresh root mass and aerial part, nematode population in 100 cm3 of soil and 10 g of roots at 45 and 70 DAP; harvest after crop maturation. Treatments with the bacterium and abamectin did not influence the height and the initial set of the soybean plants. Treatments did not influence the dry matter of the aerial part and the fresh mass of the root of the plants. A quadratic reduction of the number of P. brachyurus was observed with increasing doses of Bacillus myloliquefaciens in soybean roots at 70 DAP. The treatments using abamectin (100ml.100kg seed-1 ) and B. amyloliquefaciens, at doses of 200, 400 and 500 ml.ha-1, added 300 ml.ha-1 T. harzianum provided a reduction in the population of Helicotylenchus sp. in roots at 70 DAP. The productivity was not influenced by the different treatments.