The psyllids got their name because of their excellent jumping ability. Psyllina, its scientific name, grows between two and five millimeters in size and appears from early spring to late autumn.
How do you recognize and combat boxwood flea?
The boxwood flea is a pest that has larvae and adults on the top and bottom of leaves, young shoots and buds. It causes brown and misshapen leaves and can transmit pathogens. Fight the boxwood flea by protecting natural enemies and removing infected shoots or using oil-based insecticides.
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Greenish-yellow, quite broad and flattened larvae - often with bizarre, hair-like edges made of wax threads - suck on the top and bottom of leaves, but also on buds and young shoots. They are usually surrounded by a white wax wool. Their larvae in particular damage the plants by sucking, which initially causes the leaves to turn brown and then later wither and deform. Black sooty fungi tend to settle on the feces. The injured sucking points also serve as entry points for pathogens, some of which are even transmitted by the psyllids themselves.
Plea fleas protect themselves with wax wool
Psyllids surround themselves with waxy wool, which protects the animals from their natural enemies: gall midges, parasitic hymenoptera that lay their eggs in the psyllid larvae, predatory bedbugs, ladybirds and spiders. The waxy wool also protects the pests from their own excrement, which is sweet and sticky like honeydew.
Adult psyllids overwinter in the soil
Psyllids are reminiscent of cicadas because of their transparent wings, which are folded over the back to form a roof when at rest. However, they are not related to these; rather, both species belong to the group of plant lice. The adult psyllids overwinter in protected places in the ground or in the bark of the boxwood. In spring, the females lay tiny eggs on leaves, shoots and buds of the host plant, preferably in windless and humid places. After hatching, which takes place around the end of March, the larvae begin damaging sucking.
Identifying leaf fleas
The boxwood flea usually sits on the undersides of the leaves. You can recognize the affected leaves by the bumpy, lightened bulges from the top of the leaf. The liquid, sweet excrement - honeydew - drips down onto leaves and documents and sticks them together; but it is also important food for bees, flies and ants.
Fighting boxwood leaf flea
Conserving and promoting natural enemies is the most effective preventive measure because they ensure ecological balance. You should remove infected shoots as quickly as possible, as should the tiny yellow eggs in early spring. If there is a severe infestation, you can use an oil-based agent against leaf suckers, but you should think carefully about such a measure: this will also kill useful insects. In winter, painting the trunk white (e.g. on ball trunks) reduces the protected overwintering places for psyllids, but also affects many other small animals such as bedbugs that also overwinter there. This requires consideration on your part.
Tip
In addition to the boxwood psyllid, there are also numerous other pests on the boxwood, including spider mites, aphids, scale insects and mealybugs as well as the dreaded boxwood moth.