Activities of essential oils from three Brazilian plants and benzaldehyde analogues against Meloidogyne incognita

Abstract

SummaryThere is a demand for novel products for the control of plant-parasitic nematodes, so we characterised the effectiveness of some plant essential oils against Meloidogyne incognita and verified the efficiency of the major component from the most toxic oils and their analogues using in vitro and in vivo assays. In this study, the essential oils from Piptadenia viridiflora, Hyptis suaveolens and Astronium graveolens against M. incognita were evaluated, but only P. viridiflora oil showed toxicity toward M. incognita. Benzaldehyde was its main component according to GC-MS analysis. In in vitro assays, benzaldehyde (100 and 200 μg ml−1) and its oxime (400 μg ml−1) caused a higher rate of M. incognita second-stage juvenile (J2) mortality than the nematicide carbofuran (170 μg ml−1). Reductions of more than 90% in the number of galls and eggs, even greater than that observed with carbofuran, were observed in the assay where the J2 were placed in solutions of benzaldehyde and its oxime 48 h prior to tomato plant inoculation. Application of benzaldehyde together with M. incognita J2 to the substrate resulted only in a reduction in the number of eggs (42-65%); however, its oxime reduced both the number of galls (43-84%) and eggs (23-89%). Therefore, the P. viridiflora oil, its major component benzaldehyde, and the analogue benzaldehyde oxime are toxic to M. incognita. In two different in vivo assays, benzaldehyde oxime was confirmed as toxic to M. incognita with a greater efficacy than benzaldehyde.

Evaluation of Benzaldehyde as an Antibiotic Modulator and Its Toxic Effect against Drosophila melanogaster

“…Several essential oils have benzaldehyde as a major constituent, making these products an important source of this substance. In Brazil some example are Piptadenia viridiflora oils, Hyptis suaveolens , and Astronium graveolen [ 34 ].…”

“…Studies have already shown that several natural products have insecticidal potential. For example, benzaldehyde has activity against Meloidogyne incognita , which is a nematode that has a large impact on soybean cultivation by causing loss of productive crops, and against Strongyloides ransomi , a widely used model in the discovery of anthelmintic drugs [ 34 , 51 , 52 ]. The molecular similarity of benzaldehyde with oxygenated terpenes (all having an oxygen linked to an aromatic ring and similarities in physical properties) raises the hypothesis that the lethal damage is caused by increased oxidative stress and changes in the respiratory chain; future studies should focus on this hypothesis [ 53 , 54 , 55 ].…”

The role of Cinnamomum zeylanicum essential oil, (E)‐cinnamaldehyde and (E)‐cinnamaldehyde oxime in the control of Meloidogyne incognita

“…The activities of oximes of other substances have previously been evaluated against M. incognita . For example, benzaldehyde oxime more greatly reduced galls and eggs in tomato roots than benzaldehyde (Barros, Campos, de Oliveira, et al., 2019). Oximes have low volatility and, consequently, greater stability.…”

“…Barros, Campos, de Oliveira, et al. (2019) assessed the nematicidal activity of benzaldehyde and the oxime analogue of benzaldehyde and found that the oxime was more efficient than benzaldehyde in vivo. Therefore, this study aimed to evaluate the toxicity of the essential oil of C. zeylanicum in juveniles and second‐stage M. incognita eggs via in vitro application and greenhouse exposure.…”

Recent Advances in the Development of Environmentally Benign Treatments to Control Root-Knot Nematodes

“…EOs of Eucalyptus globulus and Pelargonium asperum significantly reduced nematode multiplication and gall formation on roots at all concentrations and increased top and root biomass. In another study, 29 plant-based EOs were evaluated against M. incognita both in vitro and in vivo on tomato ( Barros et al., 2019a ). Fourteen EOs showed nematicidal activities of 8 to 100% at a concentration of 1,000 µg/ml.…”