| General Recommendations: Viruses are small submicroscopic particles whereas phytoplasmas are much larger and resemble bacterial cells without a cell wall or distinct nucleus. Both require a living host and cause similar appearing disease symptoms which includes: a general dwarfing of the plant, lack of proper chlrophyll production resulting in a mottled appearance on foliage, yellowing and in some cases rings on leaves or fruit as well as necrotic (dead) areas. Symptoms may mimic those caused by 2,4-D damage or other disease organisms or even environmental problems. The disease can be spread by feeding insects, or mechanically through hands and tools.
Control of Viruses and Phytoplasmas:
1. Once plants are infected there is no cure. Home gardeners are best advised to rogue out and destroy diseased plants. Commercially, some plants can be specially treated by heat or propagated using micro-propagation techniques to produce virus-free propagation stock but this is beyond the scope of home gardeners.
2. Control insect vectors if they are known to transmit the disease.
3. Control weeds in the area. Since the virus or mycoplasma can be harbored in weeds in the area even if symptoms are not apparant, keeping your garden free of weeds can help control the spread of these diseases to desirable garden plants.
4. Look for varieties that are resistant to the virus. For example, if you have had a problem with cucumber mosaic virus, look for varieties to plant next year that are resistant. |
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The yellow mottling on the inner, newer leaves of this summer squash (Cucurbita pepo 'White Bush Scallop') was caused by a virus; while the white patches on the outer, older leaves indicate powdery mildew
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High resolution image available.
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A virus is suspected of stunting these bush beans (Phaseolus vulgaris) because of some of the leaves of the affected plants are crinkled and mottled.
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High resolution image available.
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Some of these bush beans (Phaseolus vulgaris) are stunted and have crinkled, mottled leaves. An unknown virus is a possible culprit.
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High resolution image available.
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The stunted, deformed and chlorotic leaves on this seed-grown avocado tree (Persea americana) are possibly the result of a virus.
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High resolution image available.
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Note the lack of chlorophyl and deformity in the leaves of this seed-grown avocado (Persea americana), possibly caused by a virus
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High resolution image available.
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