Document Type : Research Paper
Authors
1 M.Sc. student of crop protection, Crop protection department, Faculty of agriculture, Shahrekord university, Shahrekord, Iran
2 Crop protection department, Faculty of agriculture, Shahrekord university, Shahrekord, Iran
Abstract
Background and objectives: Nowadays, medicinal plants have been expanded in the biological control of many plant pathogens. It is also widely recognized that tomato is an essential product in the food industry worldwide. The root-knot nematode (Meloidogyne spp.), a hazardous parasite in tomato plants, produces gall by feeding and reproducing in the root and consequently causes biochemical and physiological changes. It also provides a suitable environment for the activity of saprophytic fungi and other soil parasites, which indirectly results in serious damage to the plant. Therefore, this study aimed to examine the effect of fenugreek, lavender, borage and purslane plant extracts on controlling the root-knot nematode.
Methodology: Separate experiments in laboratory and greenhouse conditions were conducted as a factorial experiment in the form of a completely randomized design to investigate the effect of natural compounds of fenugreek, lavender, borage and purslane on the control of root-knot nematode in tomato. Nematode-infected tomato roots were collected, and after that, a single suitable egg mass was taken and placed near the tomato Falat cultivar root system; using the single egg mass method for nematode purification, nematode was identified and then propagated at the same tomato seedlings. After 70 days, the infected roots were cut into two-centimetre pieces and exposed to 10% sodium hypochlorite solution. After that, it was passed through a 400-mesh sieve. Eventually, the obtained egg suspension was used in the laboratory and greenhouse trials. First, water, ethanol, and acetone extracts were prepared from the mentioned plants to experiment. The laboratory section assessed the effect of extracts on larval mortality and the number of egg hatching after 24, 48, and 72 hours of exposure to 0, 250, 500, 750, and 1000 ppm extracts. Afterwards, these compounds' anti-nematode activity was investigated at the greenhouse condition by adding 0, 250, 500, 750, and 1000 ppm of the water extract to the pots containing tomato seedlings and nematode-infected soil. Finally, the obtained average data were compared based on the LSD test.
Results: The results revealed that water, ethanol, and acetone extracts of fenugreek, lavender, borage, and purslane had the highest inhibition properties in hatching nematode eggs, respectively. The highest inhibition rate was dedicated to 1000 ppm of the extract. Also, the greatest inhibition of egg hatching was observed in fenugreek water extract and 1000 ppm of the extracts, respectively. The highest number of unhatched eggs was perceived in 1000 ppm of fenugreek extract and 72 h after starting the experiment. According to the results, water extract was the most effective in destroying nematode larvae, followed by ethanol and acetone extracts. Fenugreek, lavender, borage, and purslane had the highest impacts on the mortality of second-instar larvae, respectively. Also, among different extracts, the concentration of 1000 ppm had the greatest effect compared to the control. The fenugreek extract application caused gall formation at the lowest level in the experiment. After fenugreek, the lavender, borage, and purslane extracts showed the highest inhibition of gall formation on tomato roots. Regarding reducing nematode numbers in the soil, the greatest effect was related to 1000 ppm water extract of fenugreek and purslane. However, they did not significantly differ significantly from other plants using the same concentration.
Conclusion: The results of the laboratory studies showed the positive effects of water, ethanol, and acetone extracts of four medicinal plants, including fenugreek, lavender, borage, and purslane, on the prevention of egg hatching and the mortality of instar larvae of root-knot nematodes. The evaluation of the growth and development indicators showed that in fenugreek extract, a few galls were observed on roots, and the formation of galls was greatly reduced. After fenugreek, the lavender, borage, and purslane extracts showed the highest gall formation inhibition on tomato roots, respectively. The obtained data showed that fenugreek extract positively affected root-knot nematode decrease, and lavender, borage, and purslane extracts were in the next ranks, respectively.
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