Due to the relatively robust foliage, hydrangeas are not among the plants that are very often infested with lice. If the weather conditions are favourable, however, the animals can multiply like an invasion and then do not stop at the hydrangea.
You can chase away aphids on a hydrangea with nettle manure
lifestyle of lice
Almost all lice species overwinter in the egg on the host plants and hatch when it starts to get warm in spring. The first generations of the harmful insects reproduce asexually and can therefore produce a large number of offspring in a very short time. It usually takes less than a week for a new, sexually mature generation of lice to grow up. Later in the year, offspring capable of flying arise, which reproduce sexually and can also infect plants that are further away.
The look
Lice are among the most common plant pests. Most representatives of the species are only a few millimeters long and are colored green, reddish brown or black-brown, depending on the species. Mealybugs, also known as mealybugs, reach a body length of one to twelve millimeters and are easy to identify due to the dense hair.
How to recognize the infestation
Since aphids are not as small as spider mites, for example, you can usually spot them with the naked eye. Another sign of aphid infestation is the sticky, shiny honeydew coating on the leaves and leaf deformities on the young shoots.
remedy
If only individual plants are affected, it is often sufficient to spray the hydrangea with a sharp jet of water for several days in a row. This flushes the pests off the leaves. The flightless lice are unable to crawl back onto the host plant and perish.
Nettle broth: Environmentally friendly and highly effective
Undiluted nettle broth works very well against aphids. You can easily make these yourself:
- Cut a kilo of fresh nettles into pieces.
- Place plant material in a plastic bucket. Metal containers are not suitable.
- Pour ten liters of water over the greens.
- Let the broth steep for a day or two.
The nettle toxin that reliably kills the lice is effective in this environmentally friendly spray.
Biological sprays
Potassium soapy water and spraying with tea tree oil have also proven effective. If you prefer commercial insecticides, you should only choose products that are gentle on beneficial insects. Aphids have many natural enemies such as ladybugs, hoverfly larvae, assassin bugs or spiders that help you keep the number of pests on the hydrangea in check.
tips and tricks
Mealybugs, with their protective wax shell, are a bit more difficult to control and can be very stubborn. If the hydrangea is attacked by these pests, only special insecticides usually help.