Plant stem problems

In Brief

Identify pest and disease problems on plant stems. Click on the links where appropriate to find out even more about prevention and control.


The most common of all pests and almost every plant from the smallest shrub to the tallest oak tree can be infested.

Bacterial Canker

This fungus is particularly common on Cherries and Plums. The disease weakens the plant and can cause extensive dieback if not treated. Plants growing in poorly drained soil are more susceptible to this disease.

Grey Mould

This is an extremely common fungus and grows on many plants. As the name suggests a greyish fuzzy fungal growth develops over the infected area.

Honey Fungus

This is a fungus which affects the roots, trunks and stems of plants. A creamy white sheet of fungus grows between the bark and the plant tissue beneath it.


In the house, the conservatory, the sun lounge or the greenhouse, few plants will escape its attention. About 4mm long, their soft bodies are a greyish-white or pink.

Scale Insects

More sap-feeding bugs which gradually weaken plants. So-called because a colony on the leaf or stem of a plant resembles the scales on a fish.


Small dark spots on stems. Larger dark swellings again on stems often accompanied by leaf distortion. Sometimes swelling and distortion of a flower’s stamen. Black sooty powder.

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