• Powdery mildew

  colonies mostly occur in these crops. In covered roses, the colonies appear first and foremost on the upper side of the leaves. In most crops, the white [...] mildew fungi and especially in greenhouse crops they don’t play a role in the epidemics. Fungal spores germinate on the leaf surface and the germ tubes [...] fairly similar in all plant-pathogen combinations. The symptoms are white fluffy colonies, first and foremost on the upper side of the leaf. In severe epidemics

• Black rot of carrots

  only known stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause primary infection [...] three days later and sporulation within five days. Infection is both direct and through wounds and stomata. Spores are dispersed by wind and in some species [...] residues, weeds and volunteer plants. Use clean seed and propagation materials. Practice crop rotation, in particular when spores surviving in the soil are

• Damping-off

  higher temperatures in the soil or irrigation water. Pythium aphanidermatum mostly occurs in young plants and damage is more extensive in young crops. Damage [...] irreversibly. In potted plants the flower buds fall off. The side roots rot and very little of the root system survives. On the border between air and soil or [...] are in a sub-optimal condition or suffer from stress, caused for example by too much water, too high or low temperatures or sudden fluctuations in temperature

• Early blight

  only known stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause primary infection [...] three days later and sporulation within five days. Infection is both direct and through wounds and stomata. Spores are dispersed by wind and in some species [...] residues, weeds and volunteer plants. Use clean seed and propagation materials. Practice crop rotation, in particular when spores surviving in the soil are

• Angular leaf spot

  also introduced in a crop in new transplants. This bacterium is very resistant to desiccation and can survive well in dry leaves or leaves in the soil, but [...] cycle and appearance of Angular leaf spot Xanthomonas fragariae overwinters in plants and dead leaves, that become the primary source of infection in the [...] both passively and actively. Infection and disease development are favoured by temperatures around 20 °C during the day and cold nights, in combination with

• Charcoal rot

  entire plant. Life cycle and appearance of Charcoal rot The fungus survives in the soil and on crop residues as microsclerotia. In corn stalks, survival of [...] above 32 °C and dry conditions. In field crops in temperate regions it is therefore not a problem. How to prevent Charcoal rot Plant in fields with no [...] important food crops. Damage symptoms In strawberry, this pathogen causes wilting of foliage, stunting of plants and drying and death of older leaves. The youngest

• Fusarium spp.

  causes foot and/or root rot of the infected host plant, and the disease may manifest as wilting, stunting and chlorosis or lesions on the stem and/or leaves [...] ) causes dry rot of potato. The rot is dark and wet at first. The lesions are irregular and sharp-edged. In cavities, pink sporulation becomes visible. [...] produce ascospores. In general, the life cycle of different Fusarium species is similar. Fusarium overwinters for many years in the soil, and on crop residues

• Bacterial wilt, brown rot

  survives well in water and in many different soil types and on alternative hosts like weeds. It invades the plants through wounds or stomata and then spreads [...] soil-borne disease and colonises the xylem, causing bacterial wilt and brown rot in a very wide range of potential host plants. Damage symptoms In potato, field [...] cycle and appearance of Bacterial wilt, brown rot Ralstonia solanacearum is a quarantine organism in Europe and considered a bioterrorist organism in the

• 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 [...] tested and disinfected seed Use only tested and certified seed potatoes Apply strict hygiene measures in greenhouse crops: remove infected plants in closed [...] protective clothing and gloves, disinfect tools and greenhouse structures Use a crop rotation in field crops of at least two years and alternate with a non-host

• 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 [...] rain and wind and by humans and tools. Until now, no bacteria have been isolated from crazy roots. This disease seems to be caused by a change in the hormonal [...] which are first white and later turn brown. Only Rhizobium radiobacter causes galls and tumours on underground plant parts and on the crown. Furthermore