Efficacy of certain organic extracts at three concentrations on tomato plants infected with the root-knot nematode with reference to GC-MS analysis

Abstract

A greenhouse experiment was conducted to determine the efficacy of cumin, garlic, and black pepper as organic extracts at three concentrations against root-knot nematode,Meloidogyne arenaria . Garlic extract had the highest potential effects in reducing the number of galls, egg masses, and second- stage juveniles/250 g of soil by 63.97, 65.1, and 58.19%, respectively. Cumin extract was the most effective extract in reducing the number of eggs/g roots (60.91% reduction eggs/g root system). Pepper extract showed higher shoot fresh and dry weights (61.95 and 16.21 g/plant, respectively) without significant differences from other treatments. Ethanol and petroleum ether extracts were the most effective extracts in reducing the number of galls, egg masses, eggs per g, and juveniles/250 g soil. A positive correlation between concentration and the reduction of gall formation, egg masses, eggs per g, and juveniles. Ethanol extract from garlic gave the highest potential effect in reducing the number of galls, egg masses, and second-stage juveniles/250 g of soil, with percentages of reduction of 67.67, 67.9, and 65.53%, respectively. Ethanol extract of cumin was the most effective extract, as it reduced the number of eggs per gram root by 65.84%. GCMS analysis of crude ethanolic extracts of Allium sativum, Cuminum cyminum, and Piper nigrum revealed that the major compounds that were found in Allium sativum are trisulfide, di-2-propenyl with a peak area of 38.18%, disulfide, di-2-propenyl 9.95%, 4-(Methylthio) butyric acid 9.12%, propanal, 2 methyl-3-phenyl 7.86%, and tetrasulfide, di-2- propenyl 4.39%. The major compounds that were found in Cuminun cyminum Propanal, were 2-Methyl-3-Phenyl with a peak area of 29.44%, 4,5,6-trimethoxy-1H-indole-2-carboxylic acid 23.39%, 1- Ispropylidene-3-N-Butyl-2-Cyclobutene 16.48%, 2,3,3-Trimethyl-3Hindole 5.54%, and gamma-Terpinene 2.26%. Piperine with a peak area of 40.39%, 10-Hydroxy-10-(Phenylethynyl) Anthrone 5.57%, trans- Caryophyllene, 1,3-Dimethyl-4-azaphenanthrene 5.36%, Bicyclo [7.2.0] undec-4-ene, 4,11,11-trimethyl-8-methylene-5.50%, 1H-Indole- 2-carboxylic acid, and 6-(4-ethoxyphenyl) 3.09%, were the major five compounds that were found in P. nigrum. Thus, the ethanol extract of garlic had the highest potential as an alternative nematicide against M. arenaria.