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) [...] increase in number and size until they merge, after which whole sections of the leaf will die off. The fungus appears to prefer older tissue. In the field

Pierce's disease of grapevine

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. The bacteria [...] die. This happens faster in younger vines than in older ones and faster in susceptible cultivars (within 2-3 years) than in more tolerant cultivars, which [...] zinc deficiency. Infection becomes systemic more rapidly in young trees than in older trees. In the latter, it may stay limited to certain branches. When

Southern blight

was first observed in tomato crops in Florida in 1892, and it has been regularly reported as causing rotting to the root and stem in tomato plants. Significant [...] surface of the stem. In favourable conditions, the sclerotia can germinate in two forms, hyphal or eruptive, causing infection in the plants. The sclerotia [...] The sclerotia have a resistance structure resulting in longevity of more than five years in the soil, in a dry environment. Both the sclerotia and the mycelium

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 [...] 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 [...] epidemics in cereals, the ears may also be infected. In pepper, the fluffy colonies occur mostly on the underside of the leaf, because the fungus infects

Black rot of carrots

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 [...] 90% or when the leaves are wet. Small differences in optimum temperatures occur between species, but in general, the risk of Alternaria infection is larger [...] seed and propagation materials. Practice crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat

Early blight

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 [...] 90% or when the leaves are wet. Small differences in optimum temperature occur between species, but in general the risk of Alternaria infection is larger [...] seed and propagation materials. Practice crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat

Angular leaf spot

overwinters in plants and dead leaves, that become the primary source of infection in the spring. The bacteria are also introduced in a crop in new transplants [...] 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 [...] during the day and cold nights, in combination with high humidity or presence of water. These conditions occur mostly in the spring if it rains or when

Charcoal rot

°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 history of [...] and appearance of Charcoal rot The fungus survives in the soil and on crop residues as microsclerotia. In corn stalks, survival of up to 1.5 years has been [...] General Macrophomina phaseolina is a common soil fungus in warmer regions, causing charcoal rot. It has a very wide range of host crops, many of which

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 [...] 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 [...] Damage symptoms Pythium affects roots, in particular those of seedlings. Infected plants lag in growth. Seedlings start falling over, also called ‘damping-off’

Fusarium spp.

also produce ascospores. In general, the life cycle of different Fusarium species is similar. Fusarium overwinters for many years in the soil, and on crop [...] effectively with hot water) Use clean substrate in greenhouse crops Disinfect tools, machinery and irrigation water in greenhouses Prevent plant stress Ensure [...] the Fusarium solani species complex (FSSC) are capable of causing disease in many agriculturally important crops Damage symptoms of Fusarium spp. Fusarium