*2.1.1* Pepper veinal mottle virus *(PVMV)*

*Pepper veinal mottle virus* (PVMV) was first reported in Ghana in 1971 and has since then spread to other regions in Africa including Ethiopia, Kenya, Tanzania, Uganda and Rwanda [14] causing yield loss ranging from 70 to 100 % [15]. Infection of PVMV also occurs in other solanaceous crops, including eggplant and tomato [16]. Eight species of aphids have been shown to transmit the virus in a non-persistent manner, of which *Myzus persicae*, *Aphis craccivora*, *A. gossypii* and *A. spiraecola* are rated as efficient vectors [17]. Mechanical transmission also occurs through contact with infected sap, but not via seeds. Several symptoms associated with

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*Management of Viruses and Viral Diseases of Pepper (*Capsicum *spp.) in Africa*

PVMV include leaf mottle, leaf mosaic, leaf curl, vein banding, leaf ring spots, leaf deformation, leaf chlorosis, blistering and severe stunting of the whole plant [18].

Plastic mulches have been reported to reduce insect infestation and the concurrent damage associated with the insect transmission of viruses [10]. Intercropping *Capsicum* spp. with maize can also reduce the incidence of the disease compared to sole cropping [17]. The use of resistant varieties, raising of seedlings in insect-proof nursery and roguing of infected plants once detected are also crucial to reduce PVMV incidence and spread in the field. These are recommended as integrated

*Chilli veinal mottle virus* (ChiVMV) has been reported in various countries of West and East Africa including Ethiopia, Uganda and Tanzania [19]. The virus is not transmitted through seeds but is acquired mechanically and is transmitted by several species of aphids in a non-persistent manner. These vectors (*Myzus persicae*, *Aphis gossypii*, *Aphis craccivora*, *Aphis spiraecola*, *Rhopalosiphum maidis*, *Toxoptera citricida* and *Hysteroneura setariae*) retain the virus for not more than1 hour after virus acquisition [20]. The winged aphids are generally the most efficient vectors to transmit the virus from field to field and are the most difficult to control [21]. Typical symptoms caused by ChiVMV include leaf mottle and dark green vein-banding.

The effective management strategies for ChiVMV include early identification and timely disposal of infected seedlings, application of mineral oil-based insecticides in controlling aphid populations early enough during planting, careful handling of diseased-free seedlings and use of resistant varieties. In addition, removal of solanaceous weeds, which serve as alternate hosts, can reduce incidence

*Potato virus Y* (PVY) is common among solanaceous crops including pepper, potato, tomato, tobacco and many weeds [22]. It has been reported in many African countries including Zimbabwe, Zambia, Kenya, Tanzania, Malawi, Madagascar, Ethiopia and Nigeria [23]. Isolates of PVY from pepper do not infect potato and vice versa [24]. Strains of PVY infecting sweet pepper are classified by their ability to overcome resistance genes based on differential host reactions. They cause yield reductions of 20–70% in pepper production [25]. The virus is transmitted in a non-persistent manner through several species of aphids, but the green peach aphid (*Myzus persicae*) is considered generally to be the most important vector. Infection of PVY can spread during grafting, handling of plant and use of unsterilized farming equipment. The symptoms of PVY include stunting or dwarfing of plant, systemic vein clearing and banding, leaf mosaic and small deformed fruit with a mosaic pattern making them unmarketable [26].

Management of PVY is successful through the use of resistant varieties, elimination of solanaceous weeds and adjoining volunteer host plants, scheduling the time

*DOI: http://dx.doi.org/10.5772/intechopen.92266*

ways for managing PVMV infection in the field [7].

*2.1.2* Chilli veinal mottle virus *(ChiVMV)*

*2.1.2.1 Management of ChiVMV*

of ChiVMV in pepper gardens [21].

*2.1.3* Potato virus Y *(PVY)*

*2.1.3.1 Management of PVY*

*2.1.1.1 Management of PVMV*

*Management of Viruses and Viral Diseases of Pepper (*Capsicum *spp.) in Africa DOI: http://dx.doi.org/10.5772/intechopen.92266*

PVMV include leaf mottle, leaf mosaic, leaf curl, vein banding, leaf ring spots, leaf deformation, leaf chlorosis, blistering and severe stunting of the whole plant [18].
