Abstract
Among the phytosanitary constraints that are limiting the cereal production in Madagascar, a hemi-parasitic weed of type Striga in the Scrophulariaceae family is on top of the list. On this island in the Indian Ocean the species in question is Striga asiatica. The latter is responsible for both the strong decrease in production and the bad quality of the grains of rain-fed rice and corn in Madagascar, and in particular in the regions of Bogolava, Itasy, Vakinankaratra, Amoron’i Mania and Androy. A presentation of the biology of type Striga is first of all proposed, insisting on the key stages in the cycle of the association Striga/host. Two stages are subject to particular attention: the grain, being the cause of any new infestation, and the germination, which implies a molecular dialogue of “redox” type. Taking into account the research specificities carried out by Madagascan and French teams, the components of an integrated control are considered in order to try to diminish the pressure of the parasite. They request: - the selection of varieties of rice and corn that are tolerant, if not resistant, to Striga - the improvement of inorganic enrichment in order to increase the fertility of soil - the improvement of the microbial soil flora through endemic hyper-mycosis species in order to increase the mycorrhizan potential in cultivated soil - the identification of bacterium of the rhizosphere having a PGPR effect on cultivation or an inhibitor effect on the germination of the grain from Striga asiatica - the identification of fake host plants or trap plants in order to diminish the stock of parasite grains in the soil This research for targeted control methods will involve exploring different parts of the island in order to measure the fullness of the disease, identify entire set of plants hosting Striga asiatica and search for other species of Scrophulariaceae parasites likely to experience an “explosion” comparable to that of Striga asiatica. Information and education oriented policies should be implemented in order to create awareness about the problem of the Phanerogame parasites among the actors of the Madagascan agricultural community. The full term objective of this project is to define, through the creation of a network of competence and education, the means of integrated control specific to the Madagascan problem, which could be used directly by the country.
France