Potential of Inula racemosa root extract and its fractions to suppress root-knot nematode Meloidogyne incognita

Abstract

Nematicidal potential of chloroform root extract of Inula racemosa and its fractions was investigated on egg hatching and mortality of root knot nematode Meloidogyne incognita. Egg masses and second stage juveniles (J2) of M. incognita were exposed to different concentrations (0.1-8.0 mg ml-1) of I. racemosa root extract and its fractions. Observations on egg hatch were recorded on 1st, 3rd, 5th, 7th and 9th day and those of mortality studies were recorded on 2nd, 4th, 6th, 8th and 10th day, respectively. Significant mortality as well as egg hatch inhibition was observed for all the tested components at 5 %. The root extract was found to be most effective in controlling egg hatching as complete inhibition was observed at 8.0 mg ml-1 concentration on 1stday of treatment and nonpolar fraction was most effective in causing mortality of J2 of M. incognita as 100 % inhibition was observed at 6.0 and 8.0 mg ml-1 concentration on 2nd day of treatment. Maximum inhibition of egg hatching was observed for root extract at 8.0 mg ml-1 concentration and 100 % mortality was observed for root extract as well as nonpolar fraction at the same concentration. The nonpolar fraction was most effective in causing mortality as maximum mortality was observed at 6.0 and 8.0 mg ml-1 concentration throughout the exposure time. Polar fraction was least effective among all the components both in egg hatch inhibition and J2 mortality of M. incognita. Both the activities showed concentrations as well as time dependence. Results show different role of tested components on egg hatching and mortality of root knot nematode. The root extract of I. racemosa and its fractions showed a potential to develop new nematicide.