Laurel: leaf diseases

Cherry laurel (Prunus laurocerasus) is generally considered a tough evergreen but its leaves can be affected by diseases such as powdery mildew, leaf spot fungi and bacterial shothole. Affected plants or hedges look unsightly.

Laurel: leaf diseases

Quick facts

Common name Powdery mildew, leaf spot fungi and bacterial shothole
Scientific name Podosphaera pannosa, Podosphaera tridactyla, Stigmina carpophila, Eupropolella britannica and Pseudomonas syringae
Plants affected Cherry laurel (Prunus laurocerasus)
Main causes Fungi and bacterium
Timing Spring to autumn

What are laurel leaf diseases?

Leaves of laurel (Prunus laurocerasus) are often affected by powdery mildew (Podosphaera tridactyla and Podosphaera pannosa), by leaf spot fungi (Stigmina carpophila and Eupropolella britannica) and bacterial shothole (Pseudomonas syringae), all of which can cause holes, tattering and distortion in the leaves.


Laurels suffering from leaf diseases may show the following symptoms;

Powdery mildew:

  • Both powdery mildew species initially grow over the leaf surface, visible as a white powdery coating
  • Later, underlying tissues go brown and die
  • Unusually for powdery mildew infections, the brown tissue then drops out, often leaving irregular holes in the leaves, and tattered edges which look more like insect damage than disease

Leaf spot fungi and Bacterial shothole:

  • The leaf spot pathogens Stigmina and Eupropolella cause brown spots on the leaves. The centres of the spots may eventually fall out, leaving irregular holes in the leaves that resemble damage from shotgun pellets – hence 'shot-hole'
  • The bacterium Pseudomonas syringae causes water-soaked lesions that enlarge and turn tan with chlorotic (yellowing) halos. After leaf defences halt the enlargement of a lesion, the dead part eventually falls out – again, also referred to as 'shot-hole'


Non-chemical control:

  • Little can be done by cultural means to prevent infections when conditions are suitable. Plants usually grow through the problem, with new leaves being unaffected when growing conditions change
  • If the attack is very unsightly, consider trimming to remove affected leaves and encourage new growth. However, avoid heavy pruning as this will stress the plants and may aggravate the problem
  • Feeding may be helpful, although laurel is usually robust enough not to require it

Chemical control:

The fungicides tebuconazole (Bayer Fungus Fighter Concentrate), tebuconazole with trifloxystrobin (Bayer Fungus Fighter Plus), and triticonazole (Scotts Fungus Clear Ultra and Scotts Fungus Clear Ultra Gun) are approved for the control of powdery mildews on ornamental plants and would probably give useful incidental control of shothole fungi as well, although this is not claimed by the manufacturers.

The following products contain a combination of both insecticide and fungicide, enabling the control of both insect pests and disease: myclobutanil containing cypermethrin (Bayer MultiRose 2, Doff Rose Shield, Vitax Rosegarde, Westland Rose Rescue); tebuconazole containing deltamethrin (Bayer Multirose Concentrate 2), and triticonazole containing acetamiprid (Scotts Roseclear Ultra and Scotts Roseclear Ultra Gun). When a proprietary product contains an insecticide as well as a fungicide it would be preferable to use an alternative product if pests are not a problem on the plants treated.

The products SB Plant Invigorator, Resolva Natural Power Bug and Mildew Control, and Ecofective Plant Defender contain a blend of surfactants and nutrients and can be used on any edible or ornamental plants, with no harvest interval. They have a physical mode of action and may be used against powdery mildews, as well as a range of pests such as whiteflies, aphids, spider mites, mealybugs, scale insects and psyllids.

Inclusion of a product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.


Fungicides for gardeners (Adobe Acrobat pdf document outlining fungicides available to gardeners)


Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: storing and disposing safely


The powdery mildew pathogen Podosphaera pannosa also attacks roses and a distinct variety attacks peaches. Podosphaera tridactyla is found on numerous host species of the genus Prunus. As with other powdery mildews, these species grow initially over the leaf surface, feeding from the tissues but not killing them, and producing white, airborne spores which spread infection. Later the tissues die and, unusually for powdery mildew infection, drop out leaving holes and tattered edges to the leaves. An overwintering stage is of minor importance, most survival through the winter is as mycelium on the evergreen leaves. 

The shothole fungi survive the dormant season in lesions on twigs, buds or leaves and produce spores that are mainly dispersed by rain. Infections occur in young leaves, but as they expand the infection stabilises and the healthy leaf tissue pulls away from the lesion which drops out, leaving a hole. Severe attacks result in a ragged appearance to the leaves. Stigmina carpophila attacks other Prunus species but Eupropolella britannica has only been recorded on Prunus laurocerasus.

The bacterium Pseudomonas syringae is readily spread in wind-driven rain and penetrates host tissues through natural openings or wounds. The bacteria survive on plant tissues when the conditions are unfavourable to multiplication and infection.

The bacterium Xanthomonas arboricola pv. pruni also affects Prunus species (including laurel) and although not thought to be established in the UK, there have been cases confirmed by Defra. The disease is established in several European countries, where it has also been found affecting commercial production of Prunus laurocerasus. Symptoms include shothole, fruit and leaf spotting, stem cankers and severe defoliation.
Any suspected cases should be reported to;

APHA – APHA (The Animal and Plant Health Agency)

Plant Health & Seeds Inspectorate Telephone: 01904 405 138 Email:

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