If you get kohlrabi yellow leaves, then it is usually due to a nuisance: the whitefly. But don't worry, if you do it right, you will get rid of it quickly.The whiteflies suck out the plant sap When whiteflies infest your kohlrabi, it is important to act quickly. Here you will learn how to identify the widespread pests and the damage to kohlrabi, how to fight pests effectively and how to take effective preventive measures.
If you do nothing, the whiteflies can destroy the entire harvest.
Whiteflies: Detect pests and damage pattern
White flies reach a total body length of about two, sometimes up to three millimeters. They can be easily identified by the white wings and the jumping rather than flying movement pattern. The pests are found mainly on the underside of the kohlrabi leaves, which then take on a yellowish color and show a speckled to spotty pattern.
The whiteflies suck out the plant sap and leave their eggs in the leaves. The larvae are white to translucent. White fly excretions contain fructose, which in turn serves as a food source for harmful fungi such as the soot dew fungus. In the case of heavy infestation, you can see the excretions as a tough, sticky layer, the so-called honeydew, on the leaves.
Fight kohlrabi infestation with whiteflies
If you want to get rid of the whiteflies, you can take several measures at once. Among other things, you can use parasitic wasps, set up yellow boards or use an insecticide to control them.
If you pull your kohlrabi in the greenhouse, beneficial insects are ideal as conscientious helpers in the fight against pests. For example, it has proven particularly effective the use of parasitic wasps proved. The insects lay their eggs in the whitefly larvae and thus prevent a new generation from emerging. You can buy parasitic wasps in the form of fly larvae that are stuck on cardboard cards (for example available here). Simply hang these cards on the kohlrabi plants and the parasitic wasps will take care of the rest on their own.
The sticky insect traps are easy to use. Simply place them between the kohlrabi plants. Soon, many whiteflies will get caught in the adhesive film on the boards. However, do not use yellow boards and beneficial organisms such as parasitic wasps together! After all, you don't want to fight your own allies. Incidentally, yellow boards are available here.
You can also use insecticides to control white flies in a promising way. However, please make sure that you use a product that is suitable for eating vegetables. Natural insecticides based on pyrethrum are suitable e.g. particularly good. We recommend e.g. Naturen pest-free fruit & vegetables (available here).
Prevent mass infestation by whiteflies
If you want to prevent a mass infestation by whiteflies, you should remove affected leaves immediately. You must not compost the removed leaves. Otherwise, the pests could quickly spread out again in the garden. Instead, put the infected plant parts in an airtight sealed plastic bag, which you can dispose of with the household waste. Check the stock in your vegetable garden regularly and act immediately.