Viruses are pathogens for garlic. The most common is yellow dwarf virus onions.
Onion yellow dwarf virus
Synonyms – allium virus 1.
Through electron microscope the virus is as follows
Yellow dwarf virus belongs to the genus onion Potyvirus – a group of viruses which plants are natural hosts. For the first time the virus has been identified in the Netherlands in 1929
How this virus is transmitted to garlic
Carriers of the virus:
- different types of aphids
- four-legged tick garlic
- nematodes living in the soil
Aphids usually not colonized onions or garlic but during migration it can land on short time for sowing garlic or onions. At this point there is infected with virus garlic.
Yellow dwarf virus transmitted by mechanical inoculation of onion which means it does not develop in organisms carriers. They serve him only as a vehicle.
In vegetative reproduction (which is typical garlic) virus from plant material applies to plant a new crop.
The virus is not transmitted
- by contact between plants
- seeds (true for onions but not garlic, because garlic seed is not)
Spread onion yellow dwarf virus in the world
Probably onion yellow dwarf virus spread worldwide. Here is some information on the countries, which was found by us.
- In southern Italy, the high intensity of the disease 98% of infected plants garlic OYDV, reported Dovas and Vovlas, 2003
- Argentina (Lunello etc. 2007) estimated that the percentage of diseased plants OYDV ranges from 58 to 100%
- In California, US states (2005 Conci), viral infections that can reduce a lot of garlic bulbs up to 78% and virus contamination found at 12.9% in the first year and 13.1% in the second year
- Serbia (2002 Dovas) and LYSV OYDV viruses were detected in high concentrations. OYDV as the dominant viral disease pathogen garlic seriously undermines the production of this crop in Serbia.
- Iran OYDV virus is the most common of all the studied viruses in crops of onions and garlic. The average incidence varies between 40.3% and 65.5%.
The symptoms of viral disease dwarfism Yellow (onion and garlic)
- developing on the leaves yellowish spots that may look like a mosaic, strips or become almost completely yellow
- virus infected plants are stunted than healthy
- have an inflection leaves near the base, leading to a fall leaves on the ground, the plant is stunted
- infected leaves onion lose cylindrical shape and are crimped and flaps
However, these symptoms may not always. And reliably confirm the absence of the virus is possible only in the laboratory (testing by ELISA analysis)
Damage to garlic viral disease dwarfism yellow onion
Comparison (Link to study) healthy and infected groups of plants, it was found that infection OYDV leads to a significant reduction in yield:
- bulb weight loss (21.5%)
- reducing the height of plants (3.3%),
- reducing the size of bulbs: height (5.0%) and width (10.9%)
- reducing the weight of cloves (25.9%)
Research conducted in Argentina showed that lower yields in infected plants ranged from 66 to 216% (Conci etс, 2003).
However, during the studies found no difference in the number of leaves and number of teeth between infected and healthy plants, and therefore such factors are not relevant criteria for detection of viral infection.
Ways to control
Manufacturers typically use part of their harvest as planting material for the next year. This practice increases the spread of viruses and other diseases throughout the country.
Large economic losses from the use of plant material from the virus OYDV necessitate the production of virus-free planting material.
Use healthy planting material Garlic can increase productivity by more than 100% compared with garlic, infected dwarfism yellow onions (Research Mel, 2006).
Also beneficial effect in limiting the spread of the virus in garlic showed a measure establishing a plant barrier – along the perimeter of the field with garlic planted corn which serves as a barrier to migrating aphids.
Chemical methods of combating viruses onion yellow dwarf does not exist. Therefore, only the prevention:
- healthy planting material
- combating insect vectors
- destruction of infected plants