Presowing Hardening of the Host with Phenolic Acids Reduces Induction of Seed Germination in the Root Parasite Striga asiatica

Abstract

Striga asiatica (L.) Kuntze, a root parasite, causes severe loss of yield in sorghum and several other crops. The seeds of the parasite are induced to germinate by a stimulant in the host root exudate. Presowing hardening of the host with vanillic acid, caffeic acid and ferulic acid (25 ppm) reduces the induction of seed germination in the parasite by the host root exudate. The treatment causes a slight improvement in the dry matter production in the host and in addition, increases the phenolics level in the host root exudate. The latter effect might be responsible for reducing germination in Striga. If the treatment remains effective under field conditions also, it reduces significantly the incidence of Striga in cultivated fields.