Diseases
Apple canker
Neonectria ditissimaApple canker is a fungal disease that produces often deep, sunken dead areas on the branches and stems of apple, and sometimes, Sorbus trees.Symptoms
Sunken, often deep, dead areas on stems and branches
Dead bark falls from the tree
Growth above the canker dies
Fruit is often attacked, which rots and falls prematurely
What ...
Apple scab and pear scab
Venturia inaequalis and Venturia pyrinaApple scab and pear scab are fungal diseases that produce dark, scabby marks to form on the fruit and the leaves of apples and pears respectively.Symptoms
Black or dark scabby marks on the fruit
Cracked and distorted fruit
Cracked fruit may rot
Yellow, then olive-green spots and marks on leaves, which ...
Azalea gall and Camellia gall
Exobasidium japonicum and Exobasidium camelliaeAzalea gall causes fleshy growths on azaleas and other Rhododendron species. Camellia gall produces large cream-coloured swellings on camellias.Symptoms
Pale green or pinkish fleshy growths on azaleas and rhododendrons
Large swellings on camellias, replacing leaves, turning creamy-white in colour
...
Botrytis – grey mould
Botrytis cinereaBotrytis - grey mould - is a very common fungal disease that attacks a wide range of plants under damp or humid conditions, producing a fuzzy grey fungal growth.Symptoms
Fuzzy grey mould grows on affected leaves, buds, flowers and fruit
Affected parts may shrivel up and die
On fruit, infection may lead to a soft brown rot, ...
Bacterial diseases
Various bacteriaPlant diseases caused by bacteria can be extremely damaging. Luckily, there are few that are commonly seen in the UK. They produce a range of different symptoms.Symptoms
Depends on the bacteria involved and the plants they attack (see below)
What are bacterial diseases?What are bacterial diseases?
Bacterial diseases are caused by ...
Box blight
(Cylindrocladium buxicola and Pseudonectria buxi)
Box blight is a devastating fungal disease of box (Buxus) plants. It kills the leaves, resulting in extensive bare patches, and affected plants die back.Symptoms
Leaves turn brown and fall, leading to large bare patches
Leaf yellowing
Stems may die back
White or pink spore masses on the ...
Broad bean chocolate spot
(Botrytis fabae and Botrytis cinerea)
Chocolate spot is the commonest fungal disease of broad beans. It produces reddish-brown or chocolate coloured spots on all parts of the plant.Symptoms
Initially, small round, reddish-brown spots on all parts of the plant
As the disease progresses, these become much larger, irregularly shaped and turn a ...
Brown rot
(Monilinia laxa and M. fructigena)
Brown rot is a fungal disease of fruit – especially apples, pears and plums – causing the fruit to rot. Shrivelled “mummified” fruit remain in the tree, spreading the disease.Symptoms
Fruit turns brown, shrivels and rots
Buff-coloured pustules, often in concentric rings, may appear on ...
Clematis wilt
(Phoma clematidina – or physical damage)
Clematis wilt disease causes clematis plants to wilt rapidly. However, most suspected cases of wilt are actually caused by physical damage to the stems.Symptoms
Leaves and leaf stalks turn black – not brown
Leaf veins take on characteristic purple colour
Affected stems wilt rapidly – ...
Clubroot
(Plasmodiophora brassicae)
Clubroot causes swollen and distorted roots and stunted growth of brassicas – broccoli, Brussels sprouts, cabbage and cauliflower, including swede and turnip.Symptoms
Stunted growth that may take on a purplish tinge
Plants wilt, even during mild weather
Roots become extremely swollen and distorted
Growth and ...
Coral spot
(Nectria cinnabarina)
Coral spot is a fungal disease that causes woody stems and branches to die back and produces tell-tale small, coral-pink/orangey raised pustules on affected growth.Symptoms
Coral-pink/orangey raised pustules
What does it do?Nectria cinnabarina is very common and initially grows saprophytically (feeding on already dead ...
Damping off
(Fusarium, Phytophthora, Pythium, Rhizoctonia)
Damping off is a disease that affects seedlings, causing them to collapse, keel over and die. They may also become covered in a whitish, furry fungal growth.Symptoms
Seedlings collapse, keel over and die
Seedlings may be covered in whitish fungal growth
Seedlings may fail to emerge at all
What is ...
Downy mildews
(several fungus-like organisms)
Downy mildew diseases attack many ornamental and edible plants, producing a range of different symptoms, including discoloured, shrivelled and brown leaves.Symptoms
Discoloured blotches on the upper leaf surface
Stunted growth
Distorted growth
Badly affected leaves may shrivel and turn brown
Plants dying
What ...
Fungal leaf spot diseases
(Numerous fungal species – including Cercospora, Microsphaeropsis and Septoria)
Fungal leaf spot diseases attack a very wide range of plants, producing spotting or marks, in numerous different shapes, sizes and colours, on the leaves.Symptoms
Spots or marks of various shapes, sizes and colours on the leaves of plants
Distorted growth
...
Honey fungus
(Armillaria species)
Honey fungus is a devastating disease of trees, shrubs and other woody, and some herbaceous, plants. It attacks and kills the roots, then rots the dead wood.Symptoms
Woody and some herbaceous plants start to die back, often suddenly during hot, dry weather
Leaves are smaller and paler than usual
Leaves produce autumn leaf ...
Lawn diseases
(Gaeumannomyces graminis, Laetisaria fuciformis, Monographella nivalis and other species)
Lawn grasses are subject to a number of disease problems. Luckily, they rarely do very severe damage, but can lead to brown patches and areas of dead grass.Symptoms
Brown patches of grass
Grass may have a white, red or pinky tinge or fungal growth
Rings of ...
Onion white rot
(Sclerotium cepivorum)
Onion white rot is a devastating fungal disease of onions, leeks and garlic and other plants in the allium family. It causes the plants to rot, making them unusable.Symptoms
Yellowing and wilting leaves
Plants may become loose in the soil, and even topple over
The roots rot, as do onion, garlic and ornamental allium bulbs
...
Peach leaf curl
(Taphrina deformans)
Peach leaf curl is a fungal disease that attacks peaches and nectarines and sometimes almonds and apricots. It produces distorted leaves with red blisters.Symptoms
Distorted leaves that are crumpled and thickened
Red blisters on affected leaves
Affected leaves drop early
Gradual decline in overall health and vigour over a ...
Peony wilt
(Botrytis paeoniae)
Peony wilt is a common fungal disease of peonies, producing brown patches on the leaves and stems, which then collapse, and flower buds fail to develop and open.Symptoms
Brown patches on the leaves and stems
Badly affected leaves and stems collapse and die
Flower buds turn brown and fail to open
Affected flower stems ...
Phytophthora diseases
Phytophthora Root Rot (several Phytophthora species)
Phytophthora Bleeding Canker (various Phytophthora species)
Ramorum Dieback (Sudden Oak Death) (Phytophthora ramorum and P. kernoviae)
Potato and Tomato Blight (Phytophthora infestans)
Damping off (several Phytophthora species)Symptoms
Depends on the species of Phytophthora and the plants ...
Potato blight and tomato blight
(Phytophthora infestans)
Blight is a serious disease of potatoes and tomatoes, which can ruin the crops of both vegetables, making them totally inedible. Check plants regularly for symptoms.Symptoms
Rapid spreading rot of leaves, causing them to shrivel, turn brown and wither
Brown lesions may appear on the stems
Brownish rot under the skins of ...
Powdery mildews
(Several fungal species)
Powdery mildew diseases attack a wide range of plants, producing a white or greyish powdery covering on the leaves, stems and flowers. They are worse in dry conditions.Symptoms
Spreading white or greyish patches on above-ground plant parts
Stunted growth
Distorted growth
Mottled or discoloured leaves
Badly affected ...
Rose black spot
(Diplocarpon rosae)
Rose black spot is a fungal disease that attacks roses, causing black or purplish leaf blotches. Attacks usually lead to premature leaf drop, weakening the rose.Symptoms
Spreading black or purplish patches on leaves
Leaves may turn yellow around these patches
Leaves drop prematurely
Reduced growth and vigour
Reduced ...
Rusts
(Several fungal species)
Rust diseases attack a wide range of plants, usually producing orangey or yellow, rust-coloured – but not always – spots on the leaves, and sometimes stems.Symptoms
Orange or yellow spots on the upper leaf surface; some may be black or white
Lumpy, orange to brown or black pustules on the lower leaf surface
...
Snowdrop grey mould
(Botrytis galanthina) Snowdrop grey mould is a fungal disease of snowdrops, which causes the flowers, leaves and flower stems to collapse and die.Symptoms
Brown rotting on all plant parts
Flowers, leaves and flower stems collapse and die
Bulbs rot away
Fuzzy grey mould on affected plant parts
What is snowdrop grey mould?Snowdrop grey mould is ...
Sooty mould
(Numerous fungal species)
Black sooty moulds growing on leaves rarely appear of their own accord. More often than not, they are a sign that the plant is under attack from sap-sucking insects.Symptoms
Black, sooty deposit on the upper surface of leaves
Signs of sap-sucking insects on leaves above the sooty mould
White cast, shed insect skins
...
Tulip fire
(Botrytis tulipae) Tulip fire is a fungal disease that attacks tulips. Affected plants produce brown spots on the leaves. The leaves also look twisted and distorted and may wither away.Symptoms
Leaves have brown spots
Leaves become twisted and distorted
Leaves may wither away prematurely
A fuzzy grey mould may appear on affected plants
Spots ...
Virus diseases
(Various viruses) There are numerous virus diseases, which attack many ornamental and edible plants. They produce a range of different symptoms, mainly discolouration and distortion.Symptoms
Discoloured patches or patterns on the leaves
Lack of vigour and poor, stunted or malformed growth
Small, discoloured or distorted flowers and fruit
...
White blister
(several Albugo and Pustula species) White blister diseases attack plants in the Asteraceae (daisy) family and ornamental and edible Brassicaceae plants, producing white blisters and distorted growth.Symptoms
Pale spots and blotches on the upper leaf surface
These develop into white, blister-like pustules
Purple colouring surrounding the spots ...