Toxicity of Acanthus ilicifolius (L) fractions against Pratylechus spp on maize (Zea mays).

Abstract

Pollution problems associated with the control of plant parasitic nematodes, necessitated research into alternative nematode management methods. The roots of Acanthus ilicifolius were evaluated for its phytochemical constituents and nematicidal activity. Methanol and n-hexane extracts of A. ilicifolius roots were chromatographed on silica gel column (100-120μm mesh grades). Six fractions were tested on Pratylenchus spp infecting maize in the field. Generally enhanced plant development was observed in the treated plants. The polar fractions were significantly (P<0.05) more effective and compared well with a commercial nematicide (Mocap). Maize treated with the polar fractions tasselled earlier, with significantly higher yield. In the laboratory the polar fractions produced significantly higher mortality than non polar fractions with 48.07% mortality at three hours of exposure, while the non polar fractions recorded 15.22% mortality. Results of the phytochemical screening revealed the presence of alkaloids, flavonoids, terpenoids and anthraquinone, while friedlan-3-one, oleanolic acid, β-sitosterol, lupeol, quercetin, 3,3- dimethyl hexanone, and octadecanoic acid,2-hydroxyl-1,3-propanediyl ester are the bioactive compounds identified by gas chromatography-mass spectroscopy. The bioactivity of the fractions from A. ilicifolius is attributed to the presence of the above named compounds. Bio compounds from plants will go a long way in the management of plant parasitic nematodes