engleski

Effects of biostimulants on Meloidogyne hapla in carrot

The current restrictions of nematicides in carrot and need for development of environmentally safe products have contributed to increased research of biocontrol agents. A gap in knowledge still exists regarding multitrophic interactions of soil microorganisms. The northern root-knot nematode, Meloidogyne hapla Chitwood, is a economically important pest of carrot (Daucus carota L.). In Croatia, M. hapla is causing severe yield losses on carrot grown in glasshouses and in the field. Our research was conducted in a glasshouse during winter (spring crop) where we assessed the potential of commercially available plant biostimulants of microbial origin, fermented plant extracts, humic substances and stone powder to protect carrot yield against M. hapla. Initial population of M. hapla was on average 320 second-stage juveniles (J2), and final population at harvest ranged from 22.50 to 100 J2 in 100 ml of soil. The lowest, statistically significant nematode populations were detected in treatment with combination of beneficial soil microorganisms and stone powder. Combination of beneficial soil microorganisms and humic substances caused significantly greater root mass under moderately high nematode pressure, indicating improved plant tolerance. There were no significant effects of other treatments on total plant mass and index of galling. Population dynamics of M. hapla on average declined during the vegetation period in all treatments because of low soil temperatures, and marketable carrot yield was satisfactory. Beneficial soil organisms did not suppress population of M. hapla . However, promising results were obtained when combined with stone powder and humic substances. Further research is needed in conditions optimal for nematode development.

beneficial microorganisms ; root knot nematodes ; yield ; humic substances ; plant extracts ; stone powde

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