Thrips are small parasitic insects that can cause great damage in your garden. Among the many species, the onion thrips (Thrips tabaci) is particularly harmful. It punctures plant cells to feed, leading to reduced yield and altered visual quality of leeks.
🔬 Life cycle and biology
The onion thrips measures between 0.8 and 1.2 mm and is difficult to see with the naked eye. It has fringed wings and moves quickly. Here is its life cycle:
- Hibernation: Thrips overwinter in the soil, near the surface.
- Emergence: In spring, as soon as temperatures reach 11°C, adults emerge from their dormancy.
- Reproduction: The female lays about a hundred eggs under the epidermis of leek leaves.
- Larvae: After one to two weeks, the larvae hatch and feed on young leaves.
- Pupa: The larvae pupate and fall to the ground.
- Adults: New adults emerge and the cycle begins again.
This cycle can repeat up to four times per season, with a critical period from late July to early September.
🌡️ Favorable conditions
- Temperature: Below 13°C, thrips do not reproduce and cause little damage.
- Above 13°C: They become active, reproduce quickly, and damage intensifies.
🛡️ Prevention and treatment
To combat onion thrips, several natural methods can be effective:
- Insect nets: Install nets to prevent thrips from reaching plants.
- Blue sticky traps: Use traps to catch adult thrips.
- Natural insecticides: Apply solutions based on black soap, garlic, or rapeseed oil.
- Predatory mites: Introduce natural predators like Neoseiulus cucumeris to control thrips populations.
- Nematodes: Use specific nematodes to eliminate thrips larvae in the soil.
🌱 Additional tip: enrich your soil with Fertilaine
To promote healthy growth of your leeks and strengthen their resistance to pests, you can enrich your soil with Fertilaine, a natural fertilizer made from sheep's wool. Its richness in nitrogen and minerals stimulates microbial activity and improves soil quality, thus contributing to the health of your plants.
By following these tips, you can effectively protect your leeks from thrips attacks and ensure a healthy and abundant harvest.