Application of bio-silica and citronella oil nanoemulsion, neem oil, and endophytic bacteria formula for the java tea root-knot nematode population suppression

Abstract

Root-knot nematode is a potential obstacle to sustainable cultivation for the medicinal java tea plant (Orthosiphon aristatus). Some botanical/bio-pesticide formula (citronella oil and bio-silica nanoemulsion, neem oil, and endophytic bacterial Pseudomonas fluorescens and Burkholderia cepacia) were evaluated their effectiveness in root-knot nematode control. The botanical/bio-pesticides were drenched on nematode inoculated-seedling plant (var. Orsina 3 Agribun) roots in polybags, twice with 14 days interval. The experiments were randomized block design with two factors, with six treatments for the main plot and two factors as the co-plot. The treatments were replicated six times with ten plants in each replication. Three months after treatment, from the root-knot nematode population, plant growth, and leaves dry weight analysis, were indicated that all formula tested effectively suppressed the root-knot nematode population in the root, except endophytic bacterial formula. However, the synergistic nematicidal effect of the endophytic bacteria formula (1.5%) against root-knot nematode was provided by the root incorporation of bamboo charcoal compost as much as 89.68%. Citronella-oil (1%) and bio-silica (2%) nanoemulsion, and neem oil formulas (1%) effectively suppressed nematode populations (99.33% and 97.65%, and 99.66%, respectively), increasing the sinensetin content/production in comparison with control; and could be evaluated further in the plantation in the field.