Effect of different dilutions of fungal filtrate of Macrophomina phaseolina on the mortality and hatching of Meloidogyne javanicain vitro

摘要

Different dilutions of culture filtrate of Macrophomina phaseolina showed varied nematicidal effect to Meloidogyne javanica. The percentage mortality of root-knot nematode was directly proportional to the concentration of filtrate and the period for which the nematode were exposed. The rate of mortality was low in the beginning but an appreciable increase was recorded after 24 hrs of exposure to S, S/2 and S/10 dilutions. However, on the other hand, no mortality of root- knot nematode was recorded inS/100 and S/1000 concentrations even when juveniles were exposed upto 96 hours. The highest mortality of root-knot nematode was recorded in 'S' concentration after 96 hrs of exposure. Moreover, the lowest percentage of mortality was observed in S/10 dilution at 24 hrs exposure period. Similarly the different concentrations of culture filtrate of M phaseolina showed significant inhibition in the juvenile's emergence of M. javanica to varying degree except in the S/100 and S/1000 concentrations. There was a relative decrease in the hatching of M. javanica with the corresponding increase in the concentration of culture filtrate and the exposure period. The rate of hatching inhibition in the S, S/2 and S/10 concentration was low in the beginning but appreciablylncrease with the increase in the exposure period. The highest significant inhibition in the hatching of root-knot nematode was recorded in'S' concentration at 96 hrs, whereas, the lowest inhibition was found in S/10 concentration at 24 hrs. However, on the other hand, it was interesting to note that S/100 concentration of culture filtrate showed the significant stimulatory effect on the juveniles hatch.