Promising technology against nematodes

In addition to nourishing plants with N, P, K, S, Co, Mo, Zn, B, rooting and amino acids, the Pack Seed fertilizer shows potential in nematode management through induction of plant defense mechanisms.

You nematodes are among the main limiting factors for soybean productivity in Brazil, with annual losses estimated at approximately R$16 billion. Among The nematodes that cause the greatest damage are root-knot nematodes (Meloidogyne javanica e M. unexplained) and root lesions (Pratylenchus brachyurus). Controlling these nematodes is difficult, especially due to its wide geographic distribution and host range, which makes it difficult the choice of materials for crop rotation. Thus, in recent years, There has been growing interest in alternative management methods. Researches carried out over the last few years, in partnership between Spraytec and University, showed that the Pack Seed product has potential for control of nematodes, by activating defense mechanisms in the plant, which improved lignification of the cell wall, reducing its penetration and reproduction. Pack Seed is a complex mixture of natural compounds 100% biodegradable different biochemistry for seed treatment. It's a product differentiated, because in addition to the traditional Co and Mo, it provides macros and micronutrients, rooting agents and amino acids. It is a complete formulation for seed treatment, and a promising alternative in nematode management, applied alone or associated with other products. Like all methods of control have limitations, investigation is necessary to compose the integrated management, such as the study of plant nutrition, since the knowledge of the mode of action of each product can explain whether they act in isolation or in synergy, optimizing the control of nematodes in plants.

Experiment

One experiment was conducted at the State University of Maringá, in the municipality of Umuarama, in Paraná, with the aim of evaluating Pack Seed technology to direct control or activation of resistance to Meloidogyne javanica e Pratylenchus brachyurus, identify whether the product inhibits the penetration of these nematodes in the root system, it reduces reproduction, has a direct effect on hatching and evaluate the production of resistance enzymes such as peroxidase and phenylalanine ammonia-lyase in plants treated with Pack Seed.

O experiment was conducted in a greenhouse, in an entirely randomized, with six repetitions. Initially, treated and untreated soybean seeds treated with Pack Seed were sown in containers containing 700ml of soil: sand (1: 1), previously autoclaved (120ºC/2h). In the same hole as seeding, the inoculum was introduced from a population of 500 specimens of P. brachyurus, or two thousand eggs M. javanica, distributed in a 4ml solution volume. The inocula were obtained from pure populations of nematodes, kept in soybeans, in a greenhouse, for a period of two months, being extracted from the roots using the extraction process proposed by Coolen and D’Herde. The variables analyzed were penetration and reproduction factor (10, 15, 20 and 25 days after sowing), nematode hatching (seven days after sowing). sowing) and production of resistance enzymes (seven and 14 after sowing). You obtained data were subjected to analysis of variance at 5% probability of error and in case of significance the effect of the Pack Seed was evaluated by the T test at 5% significance.

Results

The Pack Seed reduced the penetration of M. javanica e P. brachyurus in the soybean roots, being 78% of the total number of M. javanica and 59% for P. brachyurus. Pack Seed caused a reduction of up to 70% in the hatching of juveniles M. javanica and mortality greater than 83% for both nematodes. The product promoted an increase in the production of the peroxidase enzyme at seven and 14 days after seeding (Figure 1) and total proteins at seven days for both nematodes. Pack Seed increased the phenylalanine-ammonium-lyase enzyme at seven days after sowing for both nematodes (Figure 2). These enzymes are related to the plant's defense mechanisms, mainly in the stiffening of the wall cell phone, which makes penetration, movement and feeding site difficult of nematodes. There was high (83%) juvenile mortality.

O product, in addition to nourishing plants with N, P, K, S, Co, Mo, Zn, B, rooting agents and amino acids for maximum expression of its productive potential, is a promising alternative in the management of nematodes by inducing the mechanisms of plant defense.

Claudia Regina Dias Arieira, State University from Maringá

Article published in issue 250 of Cultivar Grandes Culturas.