Influence de la linamarine dans la relation manioc-cochenille

Abstract

Summary: Cassava Manihot esculenta Crantz (Euphorbiaceae) is distinguished by the presence of Cyanid compounds in leaves, stems and tubers. In plant's tissues,—CN group is linked with D—glucose to form cyanogenic glucosides: mainly linamarin. In Congo, the cassava mealybug Phenacoccus manihoti Matile—Ferrero (Homoptera: Pseudococcidae) is the major pest of cassava. This insect is living mainly on genus Manihot. This oligophagy of P. manihoti towards cassava suggests that the mealybug is adapted to secondary compounds of its host plant, and more particularly to linamarin. This specialization supposes the presence of an enzymatical fittings adjusted. In fact, our results shows that this insect has a linamarase (participating in hydolysis of linamarin), an endogenous and an inductive enzyme in cassava mealybug. As other insects, P. manihoti has an enzymatical fittings hydolysing linamarin. In this insect, the use of hydolysis products is discussed. © 1997, Taylor & Francis Group, LLC.