Pochonia chlamydosporia applied via seed treatment for nematode control in two soil types

The treatment of seeds with biological control agents is one of the most convenient methods of introducing microorganisms into the root environment. Pochonia chlamydosporia is a promising biological control agent of plant-parasitic nematodes and a good root colonizer. Seed treatment with this fungus would make its application viable for soybean and grain crops. Therefore, the aim of the present work was to evaluate the influence of soil texture under the development of P. chlamydosporia applied as a seed dressing to control Meloidogyne incognita in soybean greenhouse. Soybean seeds treated with P. chlamydosporia were sown in PVC (55 cm × 10 cm) tubes containing clayey or sandy soil infested with M. incognita eggs. Sixty days after sowing, the tubes were sectioned into four parts (0.0-12.5, 12.5-25.0, 25.0-37.5, and 37.5-50.0 cm of length) to evaluate the percolation and multiplication of P. chlamydosporia at four different soil depths. The development of P. chlamydosporia in the absence of the nematode was also evaluated. It was possible to verify soil colonization by P. chlamydosporia throughout the profile of both soils tested. The fungus was able to percolate in the soil up to at least 50 cm depth and was efficient in controlling M. incognita in both sandy and clayey soils; however, in the sandy soil, the fungus presented greater colonization and percolation, which may explain why it is more efficient in controlling the nematode when applied in sandy soil.