• Bacterial wilt, brown rot

  is a plant pathogenic bacterium. It is a soil-borne disease and colonises the xylem, causing bacterial wilt and brown rot in a very wide range of potential [...] appearance of Bacterial wilt, brown rot Ralstonia solanacearum is a quarantine organism in Europe and considered a bioterrorist organism in the United [...] 250% Quarantine measures are in place, including a five-year ban on using a field for potato cropping after infection of potatoes from that field has been

• Pierce's disease of grapevine

  parts depends on the plant species: in peach, bacteria are found in high numbers in the roots, whereas in plum, high numbers are found in leaves and fruits [...] becoming more problematic in olive. Damage symptoms Grapevines: Primary infection of leaves results in leaf scorch. Part of a green leaf suddenly dies and [...] lesions occur on the underside of the leaves. These lesions start out in a light-brown colour, turning to dark-brown or necrosis. Fruits of infected trees

• Phytophthora blight

  growth on the leaves. The centre is grey-brown with a light-green edge. On the stem, elongated brown lesions occur, usually circling the stem. On potato [...] was a period of mass starvation caused by this disease which ravaged potato crops throughout Europe during the 1840s. Life cycle and appearance of Phytophthora [...] optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil in different stages: as oospores (sexual overwintering

• Apple collar rot

  off, a reduced root system and black discolouration of the roots. On the foot, dark brown lesions with sharp borders occur. Above the graft and on leaves [...] optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil in different stages: as oospores (sexual overwintering [...] pathogen grows into the stem and on the plant surface and new sporangiophores (structures containing sporangia, a type of spores) with sporangia are formed

• Black leg of seedlings

  and very little of the root system survives. On the border between air and soil or substrate the plant turns brown. A typical symptom of a Pythium infection [...] stripping of the skin from the root cortex with a finger nail. Life cycle and appearance of Black leg of seedlings Pythium belongs to the Oomycetes, a separate [...] Pythium affects roots, in particular those of seedlings. Infected plants lag in growth. Seedlings fall over (‘ damping-off ’). In slightly older plants

• Dwarf bunt

  appearance of Dwarf bunt Tilletia controversa survives as teliospores in the soil or on seed. The soil-borne teliospores are the main source of primary infection [...] y, these teliospores contaminate healthy kernels, which in turn become a source of disease in the next season. The optimum temperature for germination [...] 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

• Crazy roots, hairy roots, crown gall

  be caused by a change in the hormonal system of the plant resulting from the Rhizobium infection. Rhizobium rhizogenes puts a Ri-plasmid in the plant tissue [...] cause the growth of galls on the stems, which are first white and later turn brown. Only Rhizobium radiobacter causes galls and tumours on underground plant [...] substrate and in severe epidemics the drippers get clogged. In tomato, excessive vegetative growth occurs. Life cycle and appearance of Crazy roots, hairy

• Damping-off

  and very little of the root system survives. On the border between air and soil or substrate the plant turns brown. A typical symptom of a Pythium infection [...] mostly occurs in young plants and damage is more extensive in young crops. Damage symptoms Pythium affects roots, in particular those of seedlings. Infected [...] stripping of the skin from the root cortex with a finger nail. Life cycle and appearance of Damping-off Pythium belongs to the Oomycetes, a separate group

• Brown root rot, corky root rot

  survives in the soil and in buried tomato roots as microsclerotia. The microsclerotia germinate and produce mycelium that in turn infect the roots of tomato [...] poorly looking plants in localized areas of the greenhouse or field. The affected plants may wilt. Also, interveinal chlorosis of leaves and premature [...] more and more destruction of the root system and subsequent loss of vigour and further wilting. Life cycle and appearance of Brown root rot, corky root

• Wheat bunt

  kernels, which in turn become a source of disease in the next season. Infection is strongly correlated to temperature and precipitation in the first 11 days [...] appearance of Wheat bunt Tilletia tritici and Tilletia laevis survive as teliospores in the soil or on seed. These teliospores germinate in response to [...] The glumes are opened either on some or on all spikelets, showing the bunt (smut spore) they contain, which is larger than a normal kernel. The bunt balls