Avanços na ciência e tecnologia agrícola

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First Reports of Tobacco Witch Weed (Striga gesnerioides) Parasitizing Dalbergia melanoxylon and Richardia scabra in Zimbabwe

Koga C, Mabasa S, Mazarura U, Garwe D and Rukuni D

Striga infestation presents a major constraint to crop production in agricultural systems. The tobacco witch weed, Strigagesnerioides occurs widely in Africa and other parts of the world where it is known to parasitize mainly cowpea (Vignaunguiculata) and other dicotyledonous plants. In Zimbabwe, the parasitic weed was first confirmed in the Nyikavanhu area of Mvuma in the year 2007 and research was initiated to study this parasitic weed and recommend control strategies. A few more reports have been received of the parasitic weed infesting tobacco in other growing regions. However, despite having been reported widely on cowpea in other countries, S. gesnerioides has not been documented on this and related crops in Zimbabwe. Interestingly, in previous research conducted in Zimbabwe, it was established that cowpea induces suicidal germination of S. gesnerioides seeds but resulting in no further developmental stages such as haustorial attachment. This led to the conclusion that the species strain reported elsewhere on cowpea could be a different biotype from the one currently parasitizing tobacco in Zimbabwe. Thus it was felt that cowpea could then be used in tobacco crop rotations as a trap crop by inducing suicidal germination of parasite’s seed. This current work reports the occurrence of S. gesnerioides on other plants in addition to tobacco.