Evaluación de la eficiencia de nematicidas biológicos sobre poblaciones de Meloidogyne incognita, en el cultivo de pitahaya amarilla (Selenicereus megalanthus), a nivel de invernadero, en el cantón Joya de Los Sachas.

Abstract

The objective of this research was to determine the efficiency of biological nematicides for the control of Meloidogyne incognita populations in the yellow pitahaya crop (Selenicereus megalanthus), under greenhouse conditions, in the Joya de los Sachas canton. A randomized complete block design was applied with three replicates and the following treatments: T1: Purpureocillum lilacinum; T2: Trichoderma asperellum; T3 Purpureocillum lilacinum plus Trichoderma asperellum; T4: Biological commercial; T5: absolute control; T6: control plus nematode; seven days before and seven days after inoculation with Meloidogyne incognita. The following were evaluated: nematode severity, number of nodules and nematodes in soil and roots, leaf and root biomass. Pitahaya plants presented an index of nodulations greater than 100 in the root system (severity grade 5). In root fresh weight there were significant differences not only for the time of application but also in the leaf biomass variable. The quantification of nodules in the root system showed a significant effect for the treatments. Controller applications before nematode inoculation showed a positive effect on leaf and root biomass due to endophytic stimulation of Trichoderma spp, Purpureocillium spp on the root system and their emanation in plant development. The T1 had a negative effect by the high number of nodulations and population of nematodes, surpassing the T6; the T2 reduced 36.9% of nodulations and 21% of population in relation to the control plus nematode (T6). It is concluded that preventive applications of these antagonistic fungi favor agronomic variables, but are not very effective in controlling Meloydogine incognita. It is recommended to evaluate in vitro conditions, new concentrations of the biological controllers used in this study, in order to select highly efficient dosages in the control of Meloidogyne spp.