MANEJO BIOLÓGICO DO NEMATOIDE DE CISCO (Heterodera glycines) NA CULTURA DA SOJA

Abstract

The soy cyst nematode (Heterodera glycines) is capable of causing losses of up to 90% in soybean-producing areas. In order to increase the efficiency of the control of this nematode in infested areas and decrease the selection pressure, alternative control measures have been sought, among them, biological control. The objective of the work was to evaluate the efficiency of biological products in the treatment of soybean seeds aiming at the control of H. glycines. The experiment was conducted in a field naturally infested with H. glycines, in a randomized block design, with four replications, using the soybean cultivar Brasmax Desafio RR - 8423 RFS considered susceptible to the nematode. The evaluated seed treatments were: T1 - Control (untreated); T2 - Purpureocillium lilacinus (1 x 1010 CFU / g of PC) + Trichoderma harzianum (1 x 1010 CFU / g of PC); T3 - Trichoderma harzianum (1 x 1010 CFU / g PC); T4 - Pochonia chlamydosporia (5.2 x 107 chlamydospores / g BW); T5 - Bacillus methilotrophicus (15 g i.a.L-1); T6 - Bacillus subtilis (1.0 x 1011 CFU / g) + Bacillus licheniformis (1.0 x 1011 CFU / g). Fresh root mass (MFR), number of females / g of root, eggs / female, cyst / 100 cm3 of soil, eggs / cyst were evaluated at 30 and 60 days after sowing (DAS) and productivity in end of the crop cycle. At 60 DAS, treatment 2 showed a higher MFR, being statistically equal to treatment 3. For the variable females.g root-1, in the evaluation at 60 DAS, a reduction of the population was observed in treatments 2 and 3. In the variable eggs.-1 at 30 DAS treatment 3 was the only one that differed from the control, the reduction of eggs. Female-1 in relation to the control was more expressive in treatments 2 and 3, presenting a reduction of 34.05% and 51.30% respectively , when the average number of eggs of each treatment was performed in the 30 and 60 DAS periods. Assessing the reduction of eggs.cyst-1 in relation to the control, treatment 3 stood out. There was no statistical difference for the productivity variable.