Angular leaf spot

that become the primary source of infection in the spring. The bacteria are also introduced in a crop in new transplants. This bacterium is very resistant [...] a leaf spot disease found in strawberry. Life cycle and appearance of Angular leaf spot Xanthomonas fragariae overwinters in plants and dead leaves, that [...] resistant to desiccation and can survive well in dry leaves or leaves in the soil, but not independantly in the soil. Under humid conditions, bacteria ooze from

Early blight

humidity (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 [...] rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and barley reduce the number of surviving [...] stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause primary infection of the

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. Life [...] by humans or machinery. Pythium can survive very well in the soil or substrate in the absence of plants. Many species are entirely saprophytic, so these [...] plants. Damage symptoms Pythium affects roots, in particular those of seedlings. Infected plants lag in growth. Seedlings start falling over, also called

Apple scab

cycle and appearance of Apple scab Venturia inaequalis overwinters in the form of unripe fruiting bodies in infected fallen leaves or in lesions on twigs. [...] released and repeat the cycle of infection of new plant parts and spore production. In autumn, the fungus produces new pseudothecia in leaves that have already [...] fallen off the trees. In response to the infection, the plants produce cork as a defence against further growth of the fungus. In cultivars that are more

Bacterial wilt, brown rot

temperatures of 35-37 °C, the optimum for Race 3 is 27 °C, which makes it more dangerous in temperate regions. It survives well in water and in many different [...] causing bacterial wilt and brown rot in a very wide range of potential host plants. Life cycle and appearance of Bacterial wilt, brown rot Ralstonia s [...] quarantine organism in Europe and considered a bioterrorist organism in the United States. It is a commonly found soil-inhabitant in tropical and subtropical

Verticillium wilt

early dying of potato. Life cycle and appearance of Verticillium wilt Verticillium dahliae survives for prolonged time periods (many years) in the soil as [...] night. The symptoms may occur only in parts of the plant. Cutting the stalk horizontally reveals a slight discolouration of the vessels, brown or greenish [...] Verticillium dahliae also survives as hyphae (mycelium) in crop residues. The fungus infects the roots of plants, directly or through wounds caused by for example

Fusarium wilt

cycle, is similar to that of most Fusarium species. Fusarium overwinters for many years in the soil and on crop residues of infected plants as chlamydospores [...] plants Ensure there is adequate soil drainage Apply nitrogen in the form of nitrate instead of ammonium Prevent damage during harvest and during post-harvest [...] General Fusarium is a group of soil-borne fungi with many different species. Fusarium is widespread and can infect a range of host crops. Many species are

Grey mould

Botrytis cinerea ) is part of the foot rot complex, which causes rotting of the foot and may cause death of the plants. In cucumber and tomato the fungus [...] fungus in many environments. It survives in plant parts like bulbs and crop residues or as sclerotia (drought- and cold-resistant structures) in the soil [...] fruit. In potted plants, the cuttings die due to carry-over infection from infected parent plants. Life cycle and appearance of Grey mould Spores of grey

Fusarium head blight or scab

ascospores. In general, most Fusarium specieshave a similar life cycle. Fusarium overwinters for many years in the soil and on crop residues of infected plants [...] plants Ensure there is adequate soil drainage Apply nitrogen in the form of nitrate instead of ammonium Prevent damage during harvest and during post-harvest [...] General Fusarium is a group of soil-borne fungi with many different species. Fusarium is widespread and can infect a range of host crops. Many species are

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 [...] 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 [...] disinfection of tools, drippers, gutters etc. Adjust the work order in greenhouses to fit with the hygiene protocol Disinfect the nutrient solution in order to