Toxicity of Leaf and Stem Extracts to Tylenchorhynchus dubius
Miller, P.M.; Turner, N.C.; Tomlinson, H.
Journal of Nematology 5(3): 173-177
1973
ISSN/ISBN: 0022-300X PMID: 19319327 Document Number: 59698
Plant extracts, made by grinding 2 g of fresh tissue in 5 ml of water, were toxic to Tylenchorhynchus dubius and Hoplolaimus spp. Such extracts from leaves and stems of Phaseolus vulgaris and leaves of Nicotiana tabacum were most toxic; those from leaves of Zea mays, Lycopersicon esculentum and Rhododendron catawbiense were less toxic; and extracts of bean roots were nontoxic. Nematode movement slowed markedly within one hr in tobacco leaf extract, and within 4 hr in bean leaf extract; both extracts completely inactivated or killed 95% of the nematodes in 24 hr. Heating leaf extract for 10 min at 80 deg C eliminated toxicity. Absorption of fusicoccin, a phytotoxin produced by Fusicoccum amygdali increased the toxicity of tomato leaf extracts, whereas water extracts of acetone-extracted powder preparations of leaves were about 15-fold more toxic than water extracts of fresh tissue. Addition of homogenized leaves of bean, tobacco and tomato to soil significantly reduced nematode populations within 3 days. [AS].m.