The onion mosaic is the most damaging disease for the onion crop and it is known to all areas that have a temperate climate. Within these areas, it is present in all countries where the onion is grown and it causes serious damages to seed grown plants.
Yellow colored stripes are visible on the leaves and flower rods, starting from the base of the plants upwards. Every now and then the tissues are sunken, in the shape of a thumb. If the attack is severe, the leaves lose their rigidity and fall on the ground. The flower buds that have grown from infected bulbs are shorter, more deformed, bent and rolled downwards.
The inflorescences of the affected plants are small in size, have a low number of fertile soils, therefore the production decreases. The germinative properties of these flowers are also affected.
The bulbs belonging to the affected plants are small, a lot of them rot during storing and germinate earlier than the healthy ones.
The Onion Yellow Dwarf virus survives from one year to the following through the bulbs and seeds of the affected Allium plants, which are both planted or spontaneous. During the onion’s vegetation period, this virus spreads with the help of aphids.
Prevention and control
For seeds grown crops, we recommend using hard, not germinated bulbs and placing the crops on non-infected soils. It is also important to isolate the seeds intended crops from the bulb intended crops and a 500-m distance should be enough. It is also very important to fight any spontaneous hosts and to plant only resilient onion species.