Even the robust onions are not spared from diseases and pests. Infestation can be prevented by cleverly selecting the location and neighbors in the bed.
What diseases and pests can affect onions and how can they be prevented?
Onions can also be affected by diseases such as downy mildew and pests such as the onion fly. Preventive measures include growing resistant varieties, correct watering, airy locations, sufficient space in the bed and the use of protective nets.
Downy mildew
Downy mildew is the most common fungal disease of onions that can occur in persistently damp and cool weather. The spores of the fungus are transmitted from the diseased bulbs or come from the soil, where they are left over from the overwintered plants.
The clinical picture manifests itself in the foliage changing color. However, the discoloration is initially difficult to notice, so it can spread unhindered. If the infestation progresses, the leaves die and the tuber finds it difficult to continue growing.
Preventive measures:
- When buying seeds, pay attention to resistant varieties
- water the plants in the morning or afternoon if possible so that moisture doesn't get on the leaves overnight
- airy garden space is important
- do not arrange the rows too closely so that the plants have more space
Onion fly
The onion fly is an aggressive pest that lays eggs on young plants from April onwards. The maggots that hatch from it damage the onion by eating into it. The onion fly hatches two to three times during the year. The first generation is the most dangerous because the young plants are still developing and are not robust enough.
You can recognize the infestation by the fact that the young plants initially wilt and then their green dries up. The onions are starting to rot. You can especially notice this because you can easily pull the onions out of the ground.
The best way to prevent fly infestation is to use protective nets (€9.00 on Amazon), which you stretch over the beds. This is particularly important in the period from sowing in April until the tubers form in June, as the growing plants are not yet robust at this point. A direct proximity to carrots should also have a favorable effect. You shouldn't overdo it with fresh organic fertilizer.
Tips & Tricks
The onions are spared from an annoying pest: the snails don't like the onions, they are probably too spicy for them.
