Control of Meloidogyne incognita Using Mixtures of Organic Acids

Abstract

This study sought to control the root-knot nematode (RKN) Meloidogyne incognita using benign organo-chemicals. Second-stage juveniles (J2) of RKN were exposed to dilutions (1.0%, 0.5%, 0.2%, and 0.1%) of acetic acid (AA), lactic acid (LA), and their mixtures (MX). The nematode bodies were disrupted severely and moderately by vacuolations in 0.5% of MX and single organic acids, respectively, suggesting toxicity of MX may be higher than AA and LA. The mortality of J2 was 100% at all concentrations of AA and MX and only at 1.0% and 0.5% of LA, which lowered slightly at 0.2% and greatly at 0.1% of LA. This suggests the nematicidal activity of MX may be mostly derived from AA together with supplementary LA toxicity. MX was applied to chili pepper plants inoculated with about 1,000 J2, for which root-knot gall formations and plant growths were examined 4 weeks after inoculation. The root gall formation was completely inhibited by 0.5% MX and standard and double concentrations of fosthiazate; and inhibited 92.9% and 57.1% by 0.2% and 0.1% MX, respectively. Shoot height, shoot weight, and root weight were not significantly (P ≤ 0.05) different among all treatments and the untreated and non-inoculated controls. All of these results suggest that the mixture of the organic acids may have a potential to be developed as an eco-friendly nematode control agent that needs to be supported by the more nematode control experiments in fields.

Biological Control of Root-Knot Nematodes by Organic Acid-Producing Lactobacillus brevis WiKim0069 Isolated from Kimchi

“…Seo and Kim (2014) reported that the mixture of acetic acid and lactic acid showed higher mortality against J2 of M. incognita than each organic acid of the two organic acids, and the nematicidal activity of the mixture was mostly derived from acetic acid. It has also been known that the nematicidal activity of organic acids highly depends on acidic pH.…”

“…The galling index (GI) was assigned as follows: 0 = 0–10%, 1 = 11–20%, 2 = 21–50%, 3 = 51–80%, 4 = 81–90%, and 5 = 91–100% root galls. The control value was determined using the following equation (Seo and Kim, 2014): Control value (%) = [(GI of untreated negative control – GI of treatment)/GI of untreated negative control] × 100. The number of egg masses was counted after staining in phloxine B solution (Holbrook et al, 1983).…”

Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid

“…incognita . Seo and Kim [ 39 ] reported that a mixture of acetic acid and lactic acid had greater toxicity on M . incognita J2s than either agent alone.…”

Hydropic anthelmintics against parasitic nematodes

“…Trademark fertilizers, like Calphos (calcium phosphonate) and Magphos (magnesium and potassium phosphonate), were first shown to cause vacuole formation in the intestines of Meloidogyne incognita and M. javanica [8]. Seo and colleagues reported the occurrence of vacuoles in the mid and posterior regions of M. incognita J2 treated with mixtures of lactic and acetic acids and hypothesized the involvement of cell and tissue disruptions, as previously reported when Caenorhabditis elegans was exposed to heat-shock conditions [9]. Also, Jang and colleagues reported that the vacuolar phenotypes induced by oxalic acid and other acids may be due to osmotic imbalance leading to fluid accumulation [10].The first study to provide valuable insights regarding the composition of vacuoles was conducted by Bogneret and colleagues, who described the emergence of vacuole-like droplets in the central and tail regions of M. incognita J2s (as explained by Hasbash and colleagues) treated with indole-3-acetic acid or Hydropic anthelmintics, such as 5-iodoindole, disrupt osmoregulation causing rapid water influx into nematodes.…”