Determination of the nematicidal effect of culture filtrate of Aspergillus niger against root-knot nematode Meloidogyne incognita under controlled conditions

Aims: In this study, the effects of four different concentrations (25, 50, 75 and 100%) of culture filtrate of Aspergillus niger on the infection of Meloidogyne incognita in tomato and pepper roots under controlled conditions (24 ± 1 °C, 60 ± 5% humidity) were investigated.Methods and Results: In the study, 500 II. Juvenile larvae (J2) were used and two days after inoculation, 10 ml of each concentration of A. niger culture filtrate was applied to each potting soil. The number of gall and egg masses in the roots and the J2 density in the soil were determined and the percentages control effects of the concentrations on these parameters were calculated 8 weeks after the application. The most effective concentrations on M. incognita in tomato and pepper roots were found at 100% and 75%, and there was no significant difference between these concentrations in their effects on gall, egg mass number and J2 density in soil (P≥0.05). It was determined that the nematicidal effect of A. niger culture filtrate decreased to 30% when it was below 50% dilution. The percentage control effect on gall, egg mass number and soil J2 density at 100% concentration of the culture filtrate in tomato were 86.3, 86.2 and 82.0%, respectively, while in pepper roots it was 89.1, 88.6 and 87.2%. At 75% concentration of A. niger, the control effect on gall, egg mass number and soil J2 density was determined as 79.9, 79.2 and 73.0% in tomato, 82.9, 82.0 and 79.4% in pepper.Conclusions: It was determined that the local A. niger isolate showed high nematicidal activity against M. incognita.Significance and Impact of the Study: A. niger culture filtrate was determined as a new source of biological nematicides for the control of M. incognita in tomato and pepper.