Parasitic weeds of North-eastern region of Nigeria: a new potential threat to crop production.
A field survey was carried out in October-November 1999 in the northeastern region (Adamawa, Borno, Gombe and Yobe) of Nigeria to assess the various parasitic plants, their distribution and degree of infestation on economic crops in the region. The survey revealed that 4 families of parasitic plants are represented in the region with 7 genera and 10 species. The Scrophulariaceae family was represented by 4 genera - Alectra, Buchnera, Rhamphicarpa and Striga. Striga has the highest number of species - S. aspera, S. densiflora, S. gesnerioides and S. hermonthica, while B. hispida, R. fistulosa and A. vogelii are the only species of their genus. The Convolvulaceae, Lauraceae and Loranthaceae families had one species each in the region - Cuscuta campestris, Cassytha filiformis and Tapinanthus oleifolius, respectively. There is an observed prominence of C. campestris, R. fistulosa, B. hispida and T. oleifolius infestation and their agronomic importance is discussed.