Fusarium spp.

This species is the only Fusarium that actually grows inside the vascular system of the host plant and spreads upwards inside the plants. The other species [...] infection of the roots at the root tip, or in small wounds, for example where lateral roots branch off the tap root. F. oxysporum grows inside the roots towards [...] towards the foot of the plant and enters the vascular system. Inside the vessels, the fungus produces mycelium and many spores (microconidia), which are

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 [...] survive well in dry leaves or leaves in the soil, but not independantly in the soil. Under humid conditions, bacteria ooze from the lesions on the leaves and [...] limited by the small veins. The distinctive feature is the way the lesions look when using different light sources: when reflected light is used, the lesions

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 and [...] Adjust the work order in greenhouses to fit with the hygiene protocol Disinfect the nutrient solution in order to prevent biofilm growth inside the irrigation

Black leg of seedlings

lose their turgor or the leaf tips turn yellow, for example in flower bulbs. At first, the plants recover during the night, but later the plants wilt irreversibly [...] 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 [...] affects roots, in particular those of seedlings. Infected plants lag in growth. Seedlings fall over (‘ damping-off ’). In slightly older plants, the leaves lose

Bacterial wilt, brown rot

signs of wilting during the day which may disappear in the early stages of infection. Under conditions favourable for the bacteria, the whole plant will wilt [...] s roots on the stem. The vascular stem tissue is coloured brown and when the stem is cut, bacterial slime oozes from the wound. This is the way to distinguish [...] Infected stems show long, dark brown streaks. The vascular tissue in the tubers becomes grey-brown and the tuber eyes also turn grey-brown. This disease

Verticillium wilt

produces gum in the vessels. The presence of both the fungus and the gum causes the xylem vessels to get blocked, which in turn causes the plant to wilt [...] wind-dispersed to new hosts. In the senescent tissue, the resting mycelium or the microsclerotia are formed. The spread of the fungus by mycelium growth is [...] cause wilting of plants. The wilting starts at the lower leaves. These leaves are pale-green, then orange-yellow. In the beginning the plant seems to recover

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 [...] crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and barley reduce the number of surviving [...] (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

Apple scab

overwinters in the form of unripe fruiting bodies in infected fallen leaves or in lesions on twigs. These unripe fruiting bodies, or pseudothecia ripen in winter [...] available. They infect the plant by direct penetration of the cuticula and then grow between the cuticula and the epidermis of the plant cells. This causes [...] through the cuticula. The asexual conidia are released and repeat the cycle of infection of new plant parts and spore production. In autumn, the fungus

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 [...] crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and barley reduce the number of surviving [...] occur at the side of the stem. Life cycle and appearance of Early blight From the primary infection of leaves, Alternaria solani can spread to the flowers

Black root rot of cucurbits

a few of the roots but in severe cases all roots may be infected. At the final stage of the disease, only vascular tissue remains because the cortex (outer [...] away. Infection in the early stages of the crop results in stunted growth and smaller leaves with an intense green colour. Severe infection in this stage may [...] may kill the plants. In case of a less severe infection, the vines may wilt at a late stage of the crop, but when water supply is in any way limited during