Digitaria insularis Management and Nematode Dynamics in Off-season Maize

Abstract

Maize stands out as one of the most important crops in succession to soybean in tropic countries. However, the susceptibility of both crops to nematodes, can cause a continuous increase in the nematode population, especially in areas where there is the occurrence of weeds susceptible to the parasites. Thus, the objective was to evaluate the nematodes dynamics in a growing area with off-season maize under chemical weed management. The experiment was installed at Tuneiras do Oeste County, Brazil, designed in randomized blocks, with seven treatments and five replications, constituted by sourgrass (Digitaria insularis) management systems with glyphosate associated to herbicides inhibitors of the enzyme acetyl-CoA carboxylase (ACCase) and auxin-mimetic, and complement with glyphosate + atrazine + tembotrione in post-emergence. The effect of treatments on Pratylenchus spp. population was observed in roots and soil rhizosphere soil of D. insularis and in maize roots. Glyphosate application followed by glyphosate + atrazine was inefficient in controlling sourgrass. Management system with glyphosate + clethodim + 2.4-D followed by glyphosate + atrazine + tembotrione reduced the Pratylenchus spp. population in sourgrass, but any management system repeated this effect in maize. Management systems of D. insularis with associations of glyphosate + clethodim; glyphosate + clethodim + 2.4-D and glyphosate + fenoxaprop-p-ethyl, all followed by glyphosate + atrazine + tembotrione, showed excellent control level of sourgrass without affecting plant height, grain and rank numbers and grain yield. It is concluded that the management system using herbicides association controlled sourgrass and may interferer on Pratylenchus spp. population.