Encyclopedia
Plant diseases
Recognising symptoms, treatment and prevention.
Not sure what is wrong with your plant? Diagnose by symptomAlternaria leaf spot (early blight)
Brown to dark-brown spots appear on the leaves with characteristic concentric, zoned rings resembling a "targe…
12 plants in the atlasAmerican gooseberry mildew
On the young shoots, leaves and fruit of gooseberry and currant, especially blackcurrant, a white, mealy, deli…
3 plants in the atlasAnthracnose
Dark, sharply defined, sunken spots appear on the leaves, stems and fruit, with collapsed, rotting patches on …
7 plants in the atlasIron chlorosis (lime-induced chlorosis)
The symptom affects acid-loving plants — hydrangea, rose, rhododendron, blueberry and others — grown on alkali…
13 plants in the atlasRose black spot
Black to dark-brown spots with ragged margins on rose leaves, surrounded by yellowing of the leaf blade. Infec…
10 plants in the atlasSooty mould
On leaves, shoots and fruit a black, soot-like coating forms that can be partly wiped off with a finger. These…
18 plants in the atlasFusarium wilt
The soil-borne fungus infects the root system and enters the vascular bundles, blocking the flow of water with…
11 plants in the atlasPeach leaf curl
In spring the young leaves become puckered, thickened and curled, taking on a red or yellow-green colour with …
2 plants in the atlasClubroot
On the roots of brassicas (cabbage, cauliflower, oilseed rape, radish), characteristic swellings and thickenin…
11 plants in the atlasPowdery mildew
A white, powdery coating on leaves, shoots and buds. The leaves turn yellow, become deformed and drop prematur…
90 plants in the atlasDowny mildew
Yellow or angular (vein-bounded) spots on the upper leaf surface, matched underneath by a grey-violet or brown…
23 plants in the atlasBacterial soft rot
Infected fleshy organs — bulbs, tubers, storage roots and succulent stems — rot wet, turning into a slimy, wat…
10 plants in the atlasBrown rot (Monilinia)
On pome and stone fruit, brown, enlarging rot spots appear, on which concentrically arranged, grey-beige cushi…
13 plants in the atlasMosaic (viral disease)
A characteristic mosaic appears on the leaves — irregular, interweaving light and dark green or yellow patches…
16 plants in the atlasArmillaria root rot (honey fungus)
The fungus attacks the roots and stem base of trees and shrubs, causing their slow decline – the plants grow w…
32 plants in the atlasPine needle cast
On the needles, especially the older and previous-year ones, yellow and then brown discolourations appear in a…
3 plants in the atlasApple scab
Olive-green, velvety, blurred spots appear on the leaves and gradually darken and turn brown; heavily infected…
7 plants in the atlasBacterial canker of stone fruit
Sunken, necrotic wounds (cankers) form on the trunk and branches, from which – especially in spring – amber gu…
7 plants in the atlasEuropean canker
The disease mainly attacks apple and pear. Sunken, concentrically cracked and gradually enlarging wounds, know…
2 plants in the atlasEuropean pear rust
The disease has a two-host cycle: the pear is the main host, while juniper — especially savin and Chinese juni…
4 plants in the atlasRust
Rusty-orange to brown, powdery clusters of spores on the underside of leaves, matched on the upper side by yel…
35 plants in the atlasSeptoria leaf spot
Numerous small, round spots appear on the leaves with a lighter, greyish centre and a darker, brown margin. Wi…
11 plants in the atlasTar spot of maple
The disease affects maples, especially Norway maple and sycamore maple. In summer, large, round, raised, gloss…
5 plants in the atlasGrey mould
A grey-brown, fluffy coating of mycelium on flowers, fruit, leaves and shoots, preceded by watery, rotting spo…
57 plants in the atlasPlum pox (Sharka)
The disease attacks plum, apricot and peach, along with other species of the genus Prunus. Pale, chlorotic rin…
4 plants in the atlasVerticillium wilt
The first symptom is a sudden wilting and drying of leaves on individual branches or on one side of the crown,…
11 plants in the atlasBoxwood blight
Dark brown spots with a more distinct, darker margin appear on boxwood leaves and quickly merge together. On t…
1 plant in the atlasFire blight
Blossoms and young shoots suddenly turn brown and then black, looking as if scorched by fire — hence the name …
15 plants in the atlasPotato and tomato late blight
Dark-brown, spreading spots on the leaves (often with a lighter margin and a whitish coating on the underside …
2 plants in the atlasRoot rot (Phytophthora root rot)
The disease develops in overly wet, poorly aerated substrate and attacks the roots and the base of the stem. T…
104 plants in the atlasSclerotinia rot (white mould)
On the stems, at the base of the plants and on parts in contact with the soil, a watery, soft rot appears, cov…
5 plants in the atlasDamping-off of seedlings (black leg)
Seedlings and young transplants suddenly wilt, topple over and die, often in patches. At the base of the stem,…
13 plants in the atlas