Crescimento micelial e parasitismo de Paecilomyces lilacinus sobre ovos de Meloidogyne paranaensis em diferentes temperaturas"in vitro"

Abstract

Paecilomyces lilacinus is a soil fungus, facultative parasite of nematode eggs, which develops quickly "in vitro". The mycelial growth of P. lilacinus isolates was evaluated at different temperatures and the best isolates, regarding the capacity to parasite Meloidogyne paranaensis eggs, were chosen. P. lilacinus soil isolates from Londrina, Parana state, were evaluated. Isolation was done using serial dilution of the soils and plating it in semi-selective agar medium. The determination of mycelial growth and "in vitro" parasitism of these isolates was done using Petri plates containing potato-dextrose-agar (PDA), placed in chamber at 20ºC, 22.5ºC, 25ºC, 27.5ºC or 30ºC. The evaluation started when in one of the treatments of the fungus colonies reached the edge of the Petri plate. Parasitism was determined after 8 days of incubation, calculating the percentage of parasited eggs. The mycelial growth of P. lilacinus isolates was greatly dependent on the temperature. The fastest growth occurred at 22.5ºC. The isolates of P. lilacinus were able to infect M. paranaensis eggs in PDA medium, mostly at 25ºC.