Abstract:
Humic acid, Trichodermaharizianum, and Paecilomyceslilacinus were evaluated for their
potential to control root-knot nematodeMeloidogynejavanica in vitro and in vivo tests. Exposure
of M. javanica to increasing concentrations of humic acid significantly reduced egg hatching and
increased second stage of juveniles (J2) mortality. Egg hatch was inhibited up to 16.8%–59.8%
following exposure to 0.25%-1% humic acid. While test J2 mortality showed that mortality
increased as the concentrations of the humic acid and exposure period were increased. The
effects of humic acid, T. harzianum, and P. lilacinus, singly or combined, on egg hatch andJ2
mortality were also evaluated in another in vitro tests. The highest inhibition (85%) of egg hatch
was achieved by P. lilacinus and humic acid combined, followed by T. harzianum and humic
acid, and then by T. harzianum alone. The effect of P. lilacinus with humic acid on egg hatch
was significantly higher than that of P. lilacinus alone or of humic acid alone. On the other hand,
P. lilacinus with humic acid resulted in the highest (78%) juvenile mortality at 10 days of
exposure. In a greenhouse test, all of the three agents (the two fungi and the humic acid) were
found to be effective in reducing root galling and nematode reproduction, with different levels of
efficacy. |
