Banana bunchy top virus (BBTV; genus Babuvirus, family Nanoviridae), is one of the most serious pathogens of banana (AAA genome) and plantain (AAB genome) (Musa spp). BBTV is well established in central and southern sub-Saharan Africa (Kumar et al., 20011). It is transmitted by the banana aphid, Pentalonia nigronervosa (Homoptera: Aphididae), in a persistent manner. In July 2011, banana and plantain that displayed stunting and leaf symptoms typical of banana bunchy top disease were observed to be widespread in Dangbo Commune, Ouémé Department, Benin. To identify the cause of the disease, a roving survey was conducted in December 2011 in nine locations in Avrankou, Dangbo, Akpro-Missérété and Porto-Novo Communes, in Ouémé (Fig. 1). In each location, incidence of symptom-bearing plants was estimated from counts of 15 mats, and samples were collected for BBTV assessment. About 60% of the 94 banana mats assessed had plants exhibiting typical symptoms of BBTV infection -chlorotic leaf margins, dark green streaks on petioles, narrow leaves that bunched at the top and severe stunting (Fig. 2).Total DNA was extracted from 25 leaf samples collected from plants with symptoms; they were then tested for BBTV by polymerase chain reaction (PCR) according to the published protocols. Two oligonucleotide primer pairs, mREP-F and mREP-R, specific for a~240 bp conserved domain of BBTV DNA-mRep segment (Mansoor et al., 2005), and Scp-F and Scp-R specific for a~1075 bp BBTV DNA-S that encodes coat protein gene (Amin et al., 2008) were used for PCR amplification. The amplicons of expected size were obtained from 23 of the 25 samples analysed suggesting the presence of BBTV in the affected plants (Fig. 3). The PCR products of DNA-mRep segment amplified from the BBTV-infected banana samples collected in Zoungue (GenBank Accession No. JQ437548) and Mitro (JQ437549) were sequenced in both directions directly from the purified PCR products. These two sequences showed 100% nucleotide sequence identity with a BBTV

and 2 CARBAP BP, Douala, Cameroon Current statistics question the capacity of food-crop production to meet the challenges of food security in Central Africa. However, for local food crops like plantain, the potential for improving productivity is very high. In response to this challenge, after identification of the most serious constraints, an interdisciplinary team used participatory research and action-research tools to try and speed up the adoption of technical innovation by farmers. The project began in 1990 in South-West Province and subsequently expanded to include 100 plantain producers and 60 extension technicians in the Central and Southern Provinces of Cameroon. The approach used produced satisfactory results as far as the adoption and dissemination of methods of multiplication and cleaning of planting material were concerned but there was resistance to new cropping practices involving intercrops and crop rotation. The project resulted in major technical changes in plantain production systems in Cameroon that not only increased productivity and food security but also reduced deforestation showing that sustainable intensification is possible in sub-Saharan Africa.

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