The prevalence of viruses in pepper crops grown in open fields in the different agro‐ecological zones (AEZs) of Côte d'Ivoire was surveyed. Pepper veinal mottle virus (PVMV; genus Potyvirus) and Cucumber mosaic virus (CMV; genus Cucumovirus) were the most frequent viruses among those surveyed, while tobamoviruses (genus Tobamovirus) were detected at low frequency. PVMV showed a high heterogeneity across AEZs, which may be related to climatic, ecological or agronomical conditions, whereas CMV was more homogeneously distributed. The molecular diversity of CMV and PVMV were analysed from partial genome sequences. Despite the low number of CMV isolates characterized, two molecular groups were revealed, one corresponding to subgroup IA and the other to reassortants between subgroups IA and IB. RNAs 1 and 3 of the reassortants clustered with the IB subgroup of CMV isolates, whereas their RNA 2 clustered with the IA subgroup. Importantly, RNA 1 of CMV isolates of the IB subgroup has been shown to be responsible for adaptation to pepper resistance. The diversity of PVMV in the VPg‐ and coat protein‐coding regions revealed multiple clades. The central part of the VPg showed a high level of amino acid diversity and evidence of positive selection, which may be a signature of adaptation to plant recessive resistance. As a consequence, for efficient deployment of resistant pepper cultivars, it would be desirable to examine the occurrence of virulent isolates in the CMV or PVMV populations in Côte d'Ivoire and to follow their evolution as the resistance becomes more widely deployed.
Southern blight caused by Sclerotium rolfsii Sacc. was observed on okra (Abelmoschus esculentus) cv. Clemson Spineless in January 2010 during a survey of vegetable fields in Rubbino, Côte d'Ivoire, which is one of the most important areas for vegetable production. Plants exhibited symptoms of a dark brown lesion on the stems near the soil line. Upper roots became light to dark brown, the lower leaves wilted, turned yellow, and a white mat of fungal mycelium developed on the stem lesion. Numerous, white, spherical sclerotia formed on the infected stem and on soil surfaces around the infected plants. Sclerotia (0.5 to 1.2 mm in diameter) later turned tan to dark brown and the entire plant wilted. Eleven fields, with a total of approximately 26 ha surveyed, were affected and disease incidence reached approximately 15% in the fields. Sclerotia were collected and the fungus cultured on acidified potato dextrose agar (PDA) plates. The fungus grew rapidly on PDA and the hyphae at the edge of the colonies were large straight cells with one or more clamp connections at each septum. Secondary and tertiary hyphae were slender and lacked clamp connections. Whitish sclerotia were observed on the mycelial mats 5 to 7 days after incubation, which later turned tan to brown when mature. The fungus was identified as S. rolfsii based on the characteristics of mycelia and sclerotia (1). Sclerotia produced on PDA were used to inoculate okra seedlings under greenhouse conditions at rates of 10, 20, and 30 sclerotia per plant. Sclerotia were placed just under the soil surface around the root of 4-week-old seedlings of okra cv. Clemson Spineless. Symptoms identical to those on field samples developed on all inoculated plants. S. rolfsii was reisolated from diseased plants and the identity was confirmed. S. rolfsii has previously been reported as causing disease in Côte d'Ivoire (2). To our knowledge, this is the first report of southern blight caused by S. rolfsii on okra in this country. Okra is an important vegetable crop in Côte d'Ivoire and therefore the occurrence of southern blight and susceptibility of okra cultivars to this disease needs to be taken into account in okra production. References: (1) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996. (2) R. Resplandy et al. Ann. Epiphyt. 1:1, 1954.
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