Abstract
Sap from healthy and macana-diseased fique (Furcraea spp.) and sisal (Agave sisalana) plants mixed in varying concentrations with purified preparations of tobacco mosaic virus (TMV), caused 85 to 100 per cent reduction in TMVinduced local lesion formation (in comparison to controls without sap), when mechanically inoculated to tobacco plants (Nicotiana tabacum cv. 'xanthi-nc'). There was no difference in this capacity between healthy and diseased sap of equivalent concentration for either of the agavaceous species but sisal sap was 10 to 12 per cent more potent than fique sap at a dilution of 0.01 Evidently, the TMV-tobacco local lesion system is not one that is sensitive to those agavaceous sap factors which might explain why fique is markedly less susceptible to mechanical inoculation of the macana virus than sisal.
