Viruses
Most flowers are susceptible to infection by one or more
plant viruses. Viruses can slow plant growth and change the
appearance of foliage, flowers, and fruits. Virus-infected
leaves can become spotted, streaked, mottled, distorted,
or stunted. Veins
may lose their color or develop outgrowths. Flowers
can be dwarfed, deformed, streaked, or faded, or they can
remain green or develop into leaflike structures. Viruses
usually infect through a wound. Many are transmitted
by invertebrates, such as aphids and thrips, that feed on
plant juices. Mites, nematodes and fungi can
also transmit viruses. Viruses can spread in vegetative
plant parts, such as cuttings from infected stock plants
and in bulbs, corms, and rhizomes.
Identification
Solutions
Viruses rarely kill woody plants, but can dramatically alter
plant appearance, reducing the value. Herbaceous ornamentals
and certain vegetables are generally more susceptible to
serious injury or death from viruses, especially when plants
are young. Most plants infected with a virus cannot be cured.
Dig out and destroy virus-infected plants. Prevent spreading
viruses by using good sanitation and cultural practices.
Control nearby weeds that serve as reservoirs for viruses
and insects. Use only virus-free plant material and consider
growing virus-resistant cultivars if available.
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Virus-induced chlorotic mottling and necrosis on Begonia
Virus-infected alstroemeria plant
Concentric ring spots caused by Tomato spotted wilt virus on impatiens
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