Compatibility tested with chemical nematicide

Biological products based on Bacillus methylotrophicus, Bacillus subtilis, Trichoderma asperellum, Pochonia chlamydosporia, Metharizium anisopliae, Paecillomyces lillacinus, Trichoderma harzianun, Bacillus subtilis + B.licheniformis e beauveria bassiana are compatible with the chemical nematicide Fluopyram.

More than one hundred nematode species involving approximately 50 genera are associated with soybean crops. In Brazil, the species that cause the greatest damage are Meloidogyne javanica, Meloidogyne incognita, Heterodera glycines, Pratylenchus brachyurus e Rotylenchulus reniformis. The importance of these species for the country is due to relevant aspects, such as their endemic presence in several producing regions (M. javanica e M. unexplained), high genetic variability (H. glycines) and potential risk of damage with the increase in the area cultivated with susceptible species (P. brachyurus e R. reniformis).

The symptoms related to the attack of these phytoparasites are very similar. In areas with the presence of nematodes, it is common to find reboleiras with stunted and chlorotic plants. In extreme cases, with high population densities, plant death may occur. However, these indicators cannot be the only ones to diagnose an area with phytonematodes. The presence of reboleiras may be associated with limescale stains and chlorosis with nutritional deficiency, water deficit and soil compaction. Therefore, carrying out specific analyzes to correctly identify the nematode species present in the area is extremely important for successful management.

Several strategies can be used to manage nematodes in soybean crops, with emphasis on those based on the use of chemical and biological products. These products can generally be applied via seed treatment or planting furrows and aim to reduce the population of the pathogen and the damage caused by it.

The association of chemical and biological nematicides in the same application has been widely used nowadays. However, so that this combination of tools does not harm the performance of the products, it is of fundamental importance to understand the compatibility of these products. With the aim of evaluating the compatibility of biological products registered for the management of nematodes with the chemical nematicide Verango Prime®, two tests were conducted under controlled conditions at the Integrated Nematode Management Laboratory (Labmin) at IF Goiano – Campus Urutaí (GO) and at Agromax, in Primavera do Leste (MT).

The compatibility of the chemical product Verango Prime with other biological products available on the market that can be applied together, under laboratory conditions, was evaluated. The products evaluated in the tests were: Bacillus methylotrophicus (Onix – Lab. Farroupilha / Lallemand); Bacillus subtilis (Serenade - Bayer); Bacillus subtilis (Rizos – Lab. Farroupilha / Lallemand); Trichoderma asperellum (Quality – Lab. Farroupilha / Lallemand); Pochonia chlamydosporia (Rizotec – Stoller); Metharizium anisopliae (Metarril – Koppert); Paecillomyces lillacinus (Nemat – Ballagro); Trichoderma harzianun (Ecotrich – Ballagro); Bacillus subtilis + B.licheniformis (Presence | Quartz – FMC) and beauveria bassiana (Boveril – Koppert).

For the tests, the doses recommended by the manufacturers of the respective commercial products were used. To evaluate the compatibility of fungus-based products, the Potato–Dextrose–Agar (BDA) culture medium was used without the addition of antibiotics. For tests with bacteria-based products, the medium used was also PDA, with the addition of 1.000 milligrams of antibiotic per liter of culture medium. The evaluated products were diluted and placed in Petri dishes, 8cm in diameter, in the form of grooves with the aid of a Drigalsky loop. Three Petri dishes were used for each treatment, with two plates receiving filter paper discs soaked with Verango Prime and one plate remaining as a control containing only the biological product.

Filter paper discs measuring 1cm in diameter were dipped in the Verango Prime syrup and placed in contact with the surface of the culture medium already inoculated with the respective biocontrol agent, with five discs per plate. The plates were placed in a D.B.O growth chamber at a temperature of 26°C, with 12 hours of light and 12 hours of absence of light.

The presence of the inhibition halo in the growth of colonies around the discs was evaluated. The product that presented an inhibition halo around the paper disc was classified as incompatible and the product that did not present a halo was classified as compatible (Silva et al., 2008). For bacteria-based products, compatibility assessments were carried out after 48 hours of incubation and for fungus-based products, seven days after incubation.

The compatibility result of each biological product with the chemical nematicide Verango Prime is expressed in Table 1. It should be noted that all products were classified as compatible, since no inhibition halo was observed around the filter paper disc ( Figures 1 to 11).

Therefore, it is possible to conclude that products based on Bacillus methylotrophicus (Onyx), Bacillus subtilis (Serenade), Bacillus subtilis (Laughs), Trichoderma asperellum (Quality), Pochonia chlamydosporia (Rizotec), Metharizium anisopliae (Metarril), Paecillomyces lillacinus (Nemat), Trichoderma harzianun (Ecotrich), Bacillus subtilis + B.licheniformis (Presence), beauveria bassiana (Boveril) are compatible with the chemical nematicide Fluopiram (Verango Prime).

Fernando Godinho de Araújo, Federal Institute of Education, Science and Technology Goiano – Innovation Hub. Rio Verde, GO; Tatiane Zambiasi, Agromax Agricultural Research and Development, Primavera do Leste, Mato Grosso; Adriana Figueiredo, Bayer Crop Science