Effect of biofertilizers and Verticillium lecanii (Zimm.) Viégas applied to Canavalia ensiformis L. (Fabaceae) on the bioecology of Brevipalpus phoenicis (Acari: Tenuipalpidae)

Abstract

Two assays were conducted to evaluate the effect of biofertilizer suspensions applied to Canavalia ensiformis (L.) DC. plants on Brevipalpus phoenicis (Geijskes) bioecology. In the first assay (residual effect), the following treatments were tested: a) Distilled water (Control); b) Biofert - biofertilizer produced in a single bioreactor; c) Biomix – a mix of biofertilizers produced in four bioreactors; and d) Bio+VL - Biofert + Verticillium lecaniiI (Zimm.) Viégas. In the second assay (systemic effect) only two suspensions were tested: a) Biofert and b) Distilled water (control). In the first assay, the biofertilizer was applied once on the whole plant and mites were confined in arenas on both leaflets. In the second assay, the plants were sprayed weekly only in one leaflet and the mites were confined in arenas on the non-sprayed leaflet. In both bioassays, bioecological parameters related to survival and oviposition were evaluated. The biofertilizer effects on potential population growth during the first generation were measured by fertility life table parameters (net reproductive rate (Ro), mean generation time (T), doubling time (DT), intrinsic rate of increase (Rm) and finite rate of increase (). The biofertilizer had adverse effects on both survival and oviposition parameters. The net reproduction rates (Ro) were of 18.1; 12.9; 12.5 and 10.5 females/female (assay I) and 19.4 and 13.0 females/female (assay II), respectively for the treatments in the above-mentioned orders. These results show that the biofertilizer reduced the potential population growth of B. phoenicis in either residual or systemic effect assays.