*2.2.2* Tomato mosaic virus *(ToMV)*

Capsicum

of planting to conform with period of least aphid population, careful handling of plant seedlings especially during nursery and farming operations. Early detection and roguing of infected plants are the effective measures to reduce incidence of PVY. Additionally, intercropping pepper with maize has been found helpful in the

*Tobacco etch virus* (TEV) naturally occurs in co-infection with PVY [13]. In Africa, TEV is endemic and widespread in Madagascar and occasionally in South Africa. The virus is transmitted by several species of aphids in a non-persistent manner. Infected plants are lighter in colour and have mosaic patterns on their leaves, sometimes with dark-green banding along the leaf veins. Plants may also be

The use of cultivars with PVY resistance helps manage TEV because resistance to the two viruses is closely-linked. Additionally, pepper seedlings should be produced in protected culture system equipped with nets or screens to exclude aphids. Scheduling planting dates to avoid periods of high aphid activity early in the season and controlling weeds, volunteer host plants in and around seedlings will lower the amount of virus inoculum introduced into the crop. Application of mineral oil has

The viruses in the genus *Tobamovirus* are especially important because they do not require biological vectors for transmission. Members of this genus have flexuous filamentous ssRNA particles approximately 300 nm in length and 18 nm in diameter that can persist for years and survive many adverse environmental conditions because of their strong structural coat protein. Due to their high stability, tobamoviruses remain infectious in contaminated plant debris, compost, soil and irrigation

*Tobacco mosaic virus* (TMV) is the first ever virus to be identified. The virus infects more than 350 plant species, including at least 125 crop species such as tobacco, tomato, pepper, eggplant, potato and cucumber [28]. *Tobacco mosaic virus* has been found to infect pepper in Uganda, Tanzania, Zimbabwe, Sudan, Zambia (East Africa) and (Nigeria, Ghana) West Africa [29, 30]. The virus survives in infected plant materials for months or years and multiplies in living plant tissue but can remain dormant in dead plant tissue, retaining its infectiveness [31]. Tobacco mosaic virus spreads mainly through contact between plants, infected seeds and by mechanical means but not insect vectors. Typical symptoms of TMV infection include chlorotic leaves, mosaic patterns on leaves, leaf distortion and stunted

Management of TMV can be achieved through careful handling of plants, disinfection of farm tools, eradication of infected plants and treatment of seeds with 10% trisodium phosphate (TSP). The use of resistant cultivar to TMV infection has

management of potyviruses in pepper fields [27].

stunted, showing leaf curl and fruit distortion.

been reported to reduce incidence of TEV in pepper [10].

water. Viruses in this genus include TMV, ToMV and PMMoV [13].

growth usually associated with reduced fruit size [32].

*2.1.4* Tobacco etch virus *(TEV)*

*2.1.4.1 Management of TEV*

**2.2 Genus:** *Tobamovirus*

*2.2.1* Tobacco mosaic virus *(TMV)*

*2.2.1.1 Management of TMV*

**76**

*Tomato mosaic virus* (ToMV) has a worldwide distribution and is often endemic in African countries such as Uganda, Zambia and Cameroon [29]. The virus is one of the most resilient viruses in terms of its ability to survive outside plant cells and dead tissues. *Tomato mosaic virus* is known to infect more than 150 economically important crop species, including vegetables and ornamental plants. Natural mode of spread of ToMV is by contact with infected sap but it is also being transmitted mechanically during farming operations [6]. The occurrence of ToMV is more predominant in pepper than TMV even though both virus species produce similar symptoms on pepper. Typical symptoms include severe stunting of plants with chlorotic mosaic patterns on leaves and fruits [34]. Additional symptoms may vary depending on the plant age, virus strain and environmental condition. These include distorted leaves, which often occur with premature defoliation and necrotic (brown) patches on leaves and fruits [35].
