• Damping-off

  aphanidermatum mostly occurs in young plants and damage is more extensive in young crops. Damage symptoms Pythium affects roots, in particular those of seedlings [...] subsequently zoospores are produced. Zoospores are spores with flagellae, which enable the spores to move through water. The zoospores are chemically drawn to [...] most rapidly in wet conditions with a high water content ( > 70%) of the soil or substrate. Oospores are dispersed when soil particles are moved around

• Bacterial wilt, brown rot

  wilt and brown rot in a very wide range of potential host plants. Damage symptoms In potato, field symptoms of Ralstonia solanacearum are wilting and yellowing [...] slime produced from wounds, which is not seen in Clavibacter -infected plants. In tomato, the youngest leaves are affected first. They show signs of wilting [...] quarantine organism in Europe and considered a bioterrorist organism in the United States. It is a commonly found soil-inhabitant in tropical and subtropical

• Bacterial canker of tomato

  the plants in greenhouse crops and by water in field crops, for example through splashes of rain or irrigation. Both in greenhouses and in the field, spraying [...] white with a brown centre. In potato, the disease usually only occurs in the second half of the season. The first symptoms are wilting of the lower leaves [...] General Clavibacter is a quarantine organism in Europe, which means that strong efforts are used to prevent the bacterium from entering. When the occasional

• Root rot of carrot

  n of this disease in the rather acidic soils (of southwestern Norway). Spore germination was inhibited in nonsterile soil but not in similar soil that [...] walls and aiding in early signal transduction in host-pathogen interactions. Presence of umbelliferous plants: Inoculum can survive in perennial (umbelliferous) [...] carrots are a major problem and can lead to significant postharvest losses Several different fungal pathogens cause similar symptoms, which are collectively

• Early blight

  (RH) of over 90% or when the leaves are wet. Small differences in optimum temperature occur between species, but in general the risk of Alternaria infection [...] and propagation materials. Practice crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and [...] General The only known stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause

• Black rot of carrots

  (RH) of over 90% or when the leaves are wet. Small differences in optimum temperatures occur between species, but in general, the risk of Alternaria infection [...] and propagation materials. Practice crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and [...] General The only known stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause

• Crazy roots, hairy roots, crown gall

  growth (crazy roots). In greenhouse vegetables, the roots overgrow the substrate and in severe epidemics the drippers get clogged. In tomato, excessive vegetative [...] takes place via wounds. After infection, galls are formed which break open, releasing many bacteria. These are dispersed by rain and wind and by humans and [...] 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

• Phytophthora blight

  optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil in different stages: as oospores (sexual overwintering [...] cells which are resistant to desiccation) or mycelium. Zoospores are formed from the overwintering structures which infect the host. Zoospores are spores with [...] of Phytophthora blight Phytophthora species are very destructive organisms belonging to the Oomycetes and are therefore strictly speaking not fungi. They

• Click beetles

  in May or June in groups in the soil. They hatch about one month later and the larvae start to feed on roots. The larvae (‘wireworms’) are long, thin, [...] severe in young plants. Life cycle and appearance of Click beetles Adult Agriotis sp. are 6-10 mm long and yellowish brown to black. The eggs are laid in [...] fully grown the larvae pupate in the soil in summer. The adults appear about 4 weeks after pupation, but usually remain in the soil until the following

• Cottony soft rot

  lesions, giving this disease its name cottony soft rot. In the mycelium, big, dark sclerotia are formed. They can easily be seen with the naked eye and [...] Sclerotinia sclerotiorum ) overwinters as sclerotia and mycelium in dead and living plant material in or on the ground. Sclerotia germinate at temperatures between [...] first symptoms of a cottony soft root ( Sclerotinia sclerotiorum ) infection are water-soaked lesions at the stem base. The plant above it wilts and rots.