Effect of aqueous extract of some plants on soil micro-fauna and micro-flora in vitro

Abstract

Aqueous extract of five commonly available plant materials were evaluated for their effects on parasitic and free-living nematodes and fungi. Aqueous extract of Plumeria alba, Thevetia neriifolia, Jatropha curcas, Viscum album, Azadirachta indica and Hyptis suaveolens poit were prepared at two concentrations of 20 and 10%, with tap water as check. Parasitic nematodes (Helicotylenchus spp. and Scutellonema bradys and egg masses of Meloidogyne spp.) and free-living Rhabditis spp. were exposed to the extracts. Twenty grams each of plant materials were pounded and 20 ml of sterile water was added to make the extract. Each 400 ml of Potato Dextrose Agar + Streptomycin was amended with filtrate of an extract. A 2 mm plug of seven-day old mycelium block of Fusarium oxysporum f.sp. strigae and F. oxysporum, Telfairia isolate was inoculated each into an amended media. A media amended with 20 ml of sterile water served as check. The inhibitory effect of extract on fungus varied among the extract with P. alba and H. suaveolens poit having the greatest effect. All the extracts were lethal to parasitic and non-parasitic nematodes except J. curcas.

Keywords:

• nematodes
• fungus
• Fusarium oxysporum
• plant extract

Acknowledgement

The author is grateful to Donald Iyorche, Andrew Tina and Hamza Saidu for technical support.