Are white or black flies swarming around your carefully tended tomatoes? That's no reason to worry. Find out here how you can scare away the pests instead - with natural means and permanently.
How can I keep flies away from my tomato plants?
To keep flies away from tomato plants, you can use close-meshed insect nets, beneficial insects, yellow boards, glue boards and natural pesticides such as neem seeds. Also plant marigolds and nasturtiums and fertilize with nettle manure.
Fight whiteflies without chemicals
You do not spare tomato plants either outdoors or in the greenhouse. Whiteflies (Trialeurodes vaporariorum) are 1-2 mm small, mealy-powdered insects that multiply explosively in summer. The females lay hundreds of their white eggs on the undersides of leaves. Tiny larvae hatch from this and feast on the leaves. If the infestation pressure is high, the plant dies. This is how you take action against the pests:
- Protect the tomato plants in the bed with a close-meshed insect net
- plant marigolds and nasturtiums as underplanting
- spread beneficial insects in the greenhouse, such as parasitic wasps, ladybirds or the predatory bugs Macrolophus caliginosus
- Hang up yellow signs
- shake the plants to catch the rising swarm of flies with the vacuum cleaner
- Do not plant tomatoes too closely, no more than 2 specimens per square meter
To prevent this, make a broth from oak leaves and nettle leaves and shower it over the bed soil. Also work neem seeds into the soil, a natural pest control agent.
Repelling black flies from tomatoes
If black flies besiege your tomato plants, they are usually thrips (Thysanoptera), also known as thunderflies. Silvery blisters on the tops of the leaves and black excrement spots on the undersides signal an infestation by the 1-2 mm small insects. Their larvae develop in the root area and cause considerable damage there. How to ward off the plague:
- Hang up blue glue boards to catch the adult flies
- remove and destroy affected plant parts
- spread lacewing larvae or predatory mites in the greenhouse
- brown soil attracts thrips, so mulch with light straw
- fertilizing with nettle manure prevents thunderflies
- Repotting tomatoes in pots into fresh, disinfected substrate
Read how to recognize, treat and prevent other tomato diseases and find out about black spots and yellow leaves on tomato plants.
Tips & Tricks
Growing soil is often infected with insect eggs. To prevent fly larvae from attacking tomato seedlings during sowing, the substrate is disinfected beforehand. Put it in the oven in a fireproof dish with the lid on for 30 minutes at 180 degrees or in the microwave for 10 minutes at 800 watts.
