Crazy roots, hairy roots, crown gall

white and later turn brown. Only Rhizobium radiobacter causes galls and tumours on underground plant parts and on the crown. Furthermore, infection is ch [...] yet been defined. The assumption is that the bacteria survive in the soil, but it is possible that first infection is from the propagation material. Infection [...] break open, releasing many bacteria. These are dispersed by rain and wind and by humans and tools. Until now, no bacteria have been isolated from crazy roots

Dwarf bunt

General Tilletia controversa is a plant pathogen. It is a fungus known to cause the smut disease TCK smut in soft white and hard red winter wheats, as well [...] are generally broader and the glumes opened wider, than in plants infected with Tilletia tritici and Tilletia laevis Life cycle and appearance of Dwarf bunt [...] (smut spore) they contain, which is larger than a normal kernel. The bunt balls are grey-brown. They rupture at harvest and release black, powdery spores

Bacterial spot

development is favoured by temperatures between 24 and 30 °C and high precipitation due to rain, fog or overhead irrigation. Infection is through stomata [...] stomata and wounds. The dispersal is in windblown water drops, mechanical means such as clipping and handling and aerosols. Many isolates are resistant to [...] are also round and small to start with and slightly raised from the leaf surface. They occur on the abaxial (underside of) leaf surfaces and may enlarge into

Damping-off

irrigation water. Pythium aphanidermatum mostly occurs in young plants and damage is more extensive in young crops. Damage symptoms Pythium affects roots [...] flower buds fall off. The side roots rot and very little of the root system survives. On the border between air and soil or substrate the plant turns brown [...] symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger nail. Life cycle and appearance of Damping-off Pythium

Loose smut of wheat

sp. tritici is a basidiomyceteous fungus that affects wheat. It is also known as loose wheat smut, or loose smut of wheat. Life cycle and appearance of [...] but viability and germination rate should be checked and compensated for Use resistant cultivars Perform field checks for infected seed and prevent the use [...] during flowering and the infected seeds are the primary source of inoculum in the next crop. The fungus survives inside the seed and when the seed germinates

Apple scab

petioles and fruits and sometimes on twigs and bud scales. The lesions are olive-green. When spores are produced, the lesions become grey and fluffy. The [...] by conidia extend faster and may merge. Infected fruits and leaves may fall off prematurely. The plants’ defence mechanism is to produce corky rings around [...] to the fruit trees and will germinate if free water is available. They infect the plant by direct penetration of the cuticula and then grow between the

Cottony soft rot

wilting and death of plants. Life cycle and appearance of Cottony soft rot Cottony soft root ( Sclerotinia sclerotiorum ) overwinters as sclerotia and mycelium [...] in dead and living plant material in or on the ground. Sclerotia germinate at temperatures between 4 and 26 °C with an optimum between 13 and 15 °C. G [...] easily be seen with the naked eye and look like rat droppings. The symptoms may occur on stems but also on leaves, fruits and pods. Root infection often leads

Black leg of seedlings

flower buds fall off. The side roots rot and very little of the root system survives. On the border between air and soil or substrate the plant turns brown [...] symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger nail. Life cycle and appearance of Black leg of seedlings [...] seedlings Pythium belongs to the Oomycetes, a separate group of microorganisms and is therefore not a real fungus. It survives as oospores, resting spores which

Brown root rot, corky root rot

e disease causes more and more destruction of the root system and subsequent loss of vigour and further wilting. Life cycle and appearance of Brown root [...] General Pyrenochaeta lycopersici is a fungal plant pathogen, infecting tomatoes and aubergine. It causes brown root rot and corky root rot. Damage symptoms [...] swollen and corky and gradually break off. The corky areas often occur as horizontal bands on the roots with lengthwise cracks. No discoloration is present

Grape downy mildew

cottony growth. Shoot tips and central axis of flower clusters become distorted into a curl or corkscrew. Inflorescences and young berries turn yellow or [...] spores. Early infected clusters can turn brown, dry, and fall off; later infections cause discoloration and shriveling without sporulation (brown rot phase) [...] Grape downy mildew Plasmopara viticola is an obligate biotrophic pathogen of grapevines with sexual overwintering and asexual cycles during the growing season