Nematicidal Activity of Some Weed Extracts Against Meloidogyne javanica (Treub.) Chitwood

Abstract

Abstract: Aqueous extract of six weed species including Argemone mexicana, Sonchus asper, Abufilon indicum, Xanfhium srrumarium, Solanum nigrum and Mavastrum coromandelianum were tested for their activlty towards egg hatching and juvenile mortality of Meloidogynejavanica, the root-knot nematode. Aqueous extract of A. mexicana was most lethal to M. javanica juveniles and caused significant inhibition in egg hatching. In general, with an increase in extract concentration and duration for which the juveniles were exposed, mortality increased markedly. Results demonstrated that A. mexicanacould be exploited for the suppression of root-knot disease in crops. Kw words: Weeds, Meloidoslvne iavanica, iuvenile mortalitv, eqq hatchinq Inboduction from it 50% stock solution was obtained using sterilized A serious hurdle in nematode control is the prohibitive cost of distilledwater. nematicida~ as as their toxicity in the TO study the effects of the weed extract on egg hatching of use of antagonistic offer means for the M. ja-flica, two medium sized egg masses with 2 ml of the nematode population management and control because aqueous extract of each weed species were transferred into generally they do not leave toxic residues. Recently there has a 1 cm diameter cavity glass slide. The egg masses placed in been a growing interest in the suppressive effect of some sterile distilled water served as controls. Each treatment was plant extracts on plant parasitic nematodes IAlam er a1, 1988; replicated three times and the cavity glass slides were Akhtar ef al., 1990; Patel, 1991; Dhangar er al., 1996; arranged in a randomized complete block design. The number chandravadana er al., 1996; H ~ ~er a~~.,1 9~99; A-I~e rB ~of ha~tche~d juve niles were counted after 48 h. The egg masses a1, 20011. Plants antagonistic to parasitic nematodes have were then transferred into cavity glass slides containing 2 ml been recommended as organic amendment, intercropping, or sterile distilled water to ascertain whether the egg masses f o r crop rotation for management of nematode populations kept in the culture filtrate had been temporarily or permanently i ~ l a m er al., 1988; patel er al., 19911. ~hough a number of inactivated. he juveniles were counted again after a further weeds occur in cultivated fields often with high density, lesser 48 h period. attention has been paid to exploit the weeds for the control of To study the effects of aqueous extract of each weed species nematodes. on mortality of M. javanica, two ml of e