Pepper CMV
Cucumber Mosaic Virus (CMV) can cause severe losses in vegetables, legumes, and ornamentals. The virus is distributed worldwide, has a host range of more than 1,000 species, and is transmitted by at least 75 species of aphids. Host plants include both mono- and dicotyledonous plants, including many weed species.
Symptoms of CMV vary with viral strain, pepper genotype, and environmental conditions. Symptoms can consist of necrotic specks, necrotic line patterns, or necrotic ringspots; stunting, chlorotic mosaics, narrowing of leaves and reduction in leaf size. Fruit symptoms include irregular ripening, wrinkled or bumpy appearance, a pale green coloration, and sunken, necotic lines or ringspots. The severity of CMV infection is closely related to plant age at the time of infection. Plants infected at a young age typically develop severe symptoms including mosaics, small, deformed leaves, and significant stunting. Pepper plants tend to develop mature plant resistance to CMV, remain symptomless, do not exhibit leaf deformation or stunting, and may have few fruit symptoms.
The broad host range of CMV and the large number of aphid vectors can result in its persistence. CMV can be transmitted through the seed of some weed species which are present early in the season and can serve as an inoculum source for pepper plants. The are no reports of seed-borne CMV in pepper.
Fruit size and the number of marketable fruit may be reduced.
- Resistant and tolerant pepper cultivars are available, however resistance provides protection against only a small number of viral strains.
- Cultural practices that delay the introduction of CMV include elimination of weed hosts, timing pepper planting to avoid aphid populations and migrations, and the use of reflective mulches to deter aphids.
- Insecticides are not recommended due to their general low level of effectiveness. CMV is transmitted nonpersistently by aphids and transmission occurs too rapidly for insecticides to be effective.
- Trans-gene-mediated resistance against CMV may be possible in pepper crops.
- Plant growth promoting bacteria that induce the plants' natural defenses has been successful in tomato.
Diseases
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