**3. Conclusion**

Capsicum

*2.6.1* Tomato spotted wilt virus *(TSWV)*

stems with terminated shoots and fruits [6].

*2.7.1* Pepper vein yellows virus *(PeVYV)*

*2.6.1.1 Management of TSWV*

**2.7 Genus:** *Polerovirus*

leaves [57].

*2.7.1.1 Management of PeVYV*

**2.8 Genus:** *Potexvirus*

*2.8.1* Potato virus X *(PVX)*

*Tomato spotted wilt virus* (TSWV) causes serious crop losses in many economically important crops, including vegetables and ornamental crops. It has been reported to affect pepper in Zimbabwe in Africa [53]. The virus is transmitted in a persistent and propagative manner by several species of thrips. The western flower thrip (*Frankliniella occidentalis*) is the most efficient [54]. However, only the adult thrips that feed on infected plants transmit the virus after inoculation period of less than 48 h. *Tomato spotted wilt virus* is known to infect more than 1000 different plant species from about 80 botanical families. Symptoms of the virus can be very host-specific. Typical symptoms observed in pepper include yellowing or browning of leaves, chlorotic or necrotic ringspots on leaves and fruits, necrotic streaks on

Early detection and roguing of infected plants is important for reducing TSWV

incidence in the field. Intercropping pepper with companion crops like ginger (*Zingiber officinale*) can reduce the vector from reaching its host. Additionally, use

*Pepper vein yellows virus* (PeVYV) has been reported in Ivory Coast, Mali, Republic of Benin, Sudan and Tunisia in Africa with infection rates of up to 100%. The virus is spread in circulative and non-propagative manner by *A. gossypii* and *M. persicae* [55]. Major host plants include *Capsicum* spp. and *Solanum nigrum* [56]; however, some alternate hosts such as *Chenopodium amaranticolor*, *Curcubrita pepo*, *Datura stramonium*, *Gomphrena globose* and *Nicotiana* spp. have been reported [56]. Symptoms on cultivated pepper plants include leaf curling, deformation, reduced leaf size, puckering, interveinal yellowing, vein clearing and yellow patches on

The most effective means of controlling PeVYV is preventing its introduction. Careful sourcing of plants, keeping aphid population low, raising awareness of its

*Potato virus X* (PVX) has been reported in Ethiopia, Zambia and Zimbabwe to infect a wide range of solanaceous crops including pepper, tomato, potato and tobacco. The virus causes a range of symptoms including mottling, severe necrosis of leaves and stems and sometimes, defoliation of some cultivars. Symptoms of PVX are worsened in co-infection with other viruses, especially *Potato virus Y* [58, 59]. *Potato virus X* is transmitted mechanically and by contact between plants, but not through seeds [60]. PVX is of minor importance in pepper production [60].

symptoms will assist in preventing the establishment of the virus [56].

of insecticide is a critical measure in management of TSWV [9].

**80**

Viruses remain a primary constraint to production of high-quality *Capsicum* spp. worldwide, especially in the developing regions [1]. In Africa, weeds often become reservoir hosts for vectors and virus species that attack pepper in the field [47]. Currently, virus species in the genus *Potyvirus*, *Cucumovirus*, *Begomovirus* and *Tobamovirus* are major concern for many growers because of their effects on yield [7, 62]. The severity of infection depends on environmental conditions, host varieties and individual virus infection (**Figure 1**). Generally, these virus infections cannot be totally eradicated in many plantations where they occurred [10]. However, prompt action against the damage caused by viruses is with the use of resistant varieties and ensuring adequate phyto-sanitary conditions within the field. Therefore, awareness of local farmers on the impact of field hygiene must be improved as adjunct to using tolerant varieties. Additionally, screening of young seedlings for infection before they ever reach the field is crucial to reduce virus occurrence. Ultimately, the development of eco-friendly ways of virus disease management will help to improve yield in the pepper industry.

#### **Figure 1.**

*Possible symptoms that can be observe on pepper in the field. (A) Mosaic pattern on leaves, (B) leaf mottling, (C) leaf curl, (D) vein banding, (E) vein yellowing and (F) leaf reduction.*

Capsicum
