A pest infestation on rosemary is particularly noticeable after a winter that is too dry. Improper overwintering weakens the plant and makes it vulnerable to infestation. However, the various types of lice, flies and mites can usually be combated quite easily: immerse the rosemary in water for about 15 minutes (but not the roots!) and keep the air as moist as possible for several days, e.g. B. by covering the plant with a plastic bag with holes in it.
Rosemary has lice – mealybugs and aphids
Plant lice are considered the ultimate pests. Rosemary is primarily attacked by aphids, but also by mealybugs and mealybugs.
Aphids
Aphids sit on the underside of leaves, where they suck juice and excrete what they cannot use as a sticky mass. New shoots and leaves can be damaged and the affected plants become crippled. An aphid infestation is often accompanied by sooty mold, as this fungus lives on the honeydew excreted by aphids.
mealybugs and mealybugs
An infestation with scale insects, mealybugs or mealybugs is manifested by weakened plant growth and a crust of countless scales on the wood. These lice also suck the plant sap and excrete a sticky mass that is primarily colonized by the sooty mold fungus. You can recognize the fungal infection by a greasy, black coating on leaves and stems. Organic control can be achieved with the help of soft soap, which is used to wash off the affected areas.
Rosemary infested with mites – thrips and spider mites
A spider mite infestation is shown by small, whitish spots on the leaves. The leaves often turn lead gray to bronze. The mites themselves are very small, reddish colored animals. Mites love dry air, which is why they can usually cope well with significantly increased humidity. Thrips, often better known as thunderstorm animals, also occur especially when it is too dry.
Whiteflies on rosemary
The tiny whiteflies usually show themselves through white dots that appear on the underside of the leaves. In addition, the leaves become mottled and turn yellow. Like plant lice, the whitefly secretes a sugary secretion that promotes colonization with the sooty mold fungus. It occurs more frequently in warm, humid summers. Affected leaves should be removed immediately. The entire plant is then treated with a soft soap solution.
Tips & Tricks
Pests can also be combated biologically effectively by using beneficial insects. Use predatory mites against spider mites, parasitic wasps against whiteflies, lacewings against aphids and thrips and ladybirds against aphids, mealybugs and mealybugs.