Do you have bare spots and brown spots in your grass? Do you see brown, tube-shaped larvae without legs under the sod? Then you have a leatherjacket problem. Leatherjackets are the larvae of crane flies. They feed on grass roots. In doing so, they bite onto the base of grass shoots and pull them underground, causing the bald spots that you see. Leatherjackets can also damage vegetable gardens and flower beds. When it's damp, they come up towards the surface, especially in the evening. You can fight leatherjackets with C-green. What is C-green? We'll explain below!
What is C-green?
C-green is a biocontrol agent that is effective against young leatherjackets. It consists of Steinernema carpocapsae nematodes. These nematodes attack young, recently hatched leatherjackets. The nematodes have a symbiotic relationship with bacteria that are deadly to leatherjackets.
When you spread these nematodes over your lawn, they go looking for the leatherjackets in the ground. They then penetrate into the body of the larva and infect it with bacteria. After 3 to 5 days, the larva stops eating and dies. New generations of nematodes form inside dead host leatherjackets. They leave the dead host and go searching for new ones.
The nematodes remain active in the soil for up to 6 weeks. In order to ensure that the nematodes will keep working, the soil must remain moist for this 6-week period. The soil temperature must also be at 12°C or warmer. Soil temperature is much more stable than air temperature. You can find the soil temperature in your location by looking it up online.
How to apply leatherjacket nematodes?
- Work on a cloudy day (a rainy day is ideal), or in the evening. Nematodes cannot tolerate the sun's UV rays.
- First cut the grass short. If there's a thick layer of thatch, first remove it.
- Wet the grass.
- Dissolve the nematodes in water and then dilute them according to the area to be treated. Always use the nematode concentrate immediately; it cannot be stored for later use.
- With our nematode sprayer or with a watering can, spray or pour the mixture over the affected spots and the surrounding environment. If you have many bald spots, treat the entire lawn.
- Afterwards, water the grass further so that the nematodes can penetrate deep into the soil.
- Keep the soil moist for at least 2 weeks, up to 6 weeks.
The nematode sprayer
If you have to treat a large area, you can use our nematode sprayer. This sprayer has been specially developed to spray nematodes in the garden. It can save you a lot of time compared to pouring with a watering can.
You put some of the prepared concentrate in the reservoir of the nematode sprayer. Connect it to the garden hose and start spraying. The nematode sprayer mixes the nematodes with the water from the garden hose in the right proportion.
When to use leatherjacket nematodes?
The best time to control crane fly larvae is from September to mid-October. Then all crane flies have laid their eggs and there are small, easy-to-control leatherjackets in the lawn. The species Tipula oleracea also lays eggs in the spring. If you have this species in your lawn or garden, you can also treat them with nematodes from mid-May to the end of June.
Two types of crane flies
There are two main species that cause damage in Belgium and the Netherlands.
- Tipula paludosa: This crane fly lays its eggs in the ground in August. After 2 weeks the first larvae come out. You can treat these young larvae from the beginning of September to mid-October.
- Tipula oleracea: This species has 2 generations a year. The first generation of larvae come out in the summer. You can treat them from mid-May to the end of June. The second generation comes out in the fall. You treat them from the beginning of September to mid-October.
So, regardless of which species you have in your lawn, you should definitely treat in September through October. And if you have Tipula oleracea, then you can treat an additional time in May or June.
Questions?
Biogrowi is a pioneer in bringing effective, pesticide-free biocontrol to the consumer market in western Europe. We have more than 30 years of experience. If you have any questions, please feel free to contact us. We will be happy to help you!