• Pierce's disease of grapevine

  along the margin or the tip from early to midsummer. The necrotic area spreads over the leaf from the margin and is marked by a chlorotic band. In the beginning [...] substance, in the vessels. The bacteria, gum and tyloses block the vessels, causing the plants to wilt. Transport to different plant parts depends on the plant [...] in the leaves to neighbouring peach trees with the bacteria mainly in the roots is much more successful than the other way around. In general, the low

• Angular leaf spot

  lesions on the underside of the leaf. They enlarge to angular spots, often limited by the small veins. The distinctive feature is the way the lesions look [...] visible on the upper side of the leaf as irregular spots which are first reddish brown and then become necrotic. The foliar symptoms are the most important [...] conditions are humid, a viscous bacterial exudate forms on the underside of the leaf. This exudate changes to a white film when it dries. Lesions may merge as they

• Loose smut of wheat

  survives inside the seed and when the seed germinates, the mycelium of the fungus grows upwards inside the plant into the growing tip and the seed primordia. It [...] Loose smut of wheat The seeds are infected during flowering and the infected seeds are the primary source of inoculum in the next crop. The fungus survives [...] invisible until head emergence. The first sign of infection is the appearance of a smutted ear. Instead of normal tissue, the ear contains a mass of olive-brown

• Downy mildew of Cucurbits

  For most downy mildews, the optimum temperature is around 15 o C and the closer the temperature is to this, the shorter the leaf wetness period that is [...] Inside the plant, the pathogens produce haustoria, small organs with which the pathogen can take up nutrients from the living plant cells. The pathogens [...] brown. On the underside of the leave fluffy growth appears which is first white and later turns grey-brown. This is actually the sporulation of the pathogens

• Cottony soft rot

  base and the roots, whereas the ascospores infect the above-ground plant parts. In greenhouses, usually only mycelium is produced by the germinating sclerotia [...] sclerotia. The fungus grows quite rapidly inside the plant and kills the host cells. On the infected plant tissue white, fluffy mycelium occurs with new [...] new dark sclerotia. The fungus also infects seeds and tubers, thereby creating a source of infection for the next crop. The dispersal to neighbouring plants

• Fusarium wilt

  oxysporum is the only Fusarium that actually grows inside the vessel system of the host plant and spreads upwards inside the plants. The other species [...] Fusarium oxysporum is the species causing vascular wilt. First the leaves turn yellow and wilt, mostly on one side of the plant. Finally, the whole plant wilts [...] place as infection of the roots at the root tip or in small wounds, for example where lateral roots branch off from the tap root. How to prevent Fusarium wilt

• Foot rot of cereals

  penetrate the host's tissues. Inside the plant, the fungus colonizes the root and lower stem, leading to the characteristic symptoms of foot rot. As the disease [...] staining of the lower nodes. Long dark streaks may also appear at the stem base. On older plants, infection can produce a true foot rot, where the stem base [...] ears often show above the point of infection around the milky ripe stage (GS 75). Later infections may result in infection of the grain without obvious

• Leaf stripe

  and chlorotic and may merge. Eventually this leads to the death of the leaf. The leaf splits at the end which makes it look shredded. This is typical for [...] during the cropping season. The fungus is seed-borne and this systemic infection is the only source of primary infection. The fungus spreads from the seed [...] first occur on the first, second and third leaf and subsequently on other leaves. Yellow stripes are formed at the base of the leaf and the leaf sheath.

• Loose smut of barley

  survives inside the seed and when the seed germinates, the mycelium of the fungus grows upwards inside the plant into the growing tip and the seed primordia. It [...] smut of barley The seeds are infected during flowering and the infected seeds are the primary source of inoculum in the next crop. The fungus survives [...] invisible until head emergence. The first sign of infection is the appearance of a smutted ear. Instead of normal tissue, the ear contains a mass of olive-brown

• Gummy stem blight

  be recognized from the outside by the small narrowing of the tip of the mature fruits. The symptoms on stems, leaves and inside the fruits may occur together [...] brown lesions on the foot and higher up on the stem. On the lesions, golden-brown gummy drops occur, hence the name gummy stem blight. On the lesions, black [...] ascospores are the main source of dispersal of disease upwards in the crop and the conidia for spread of the disease downwards. How to prevent Gummy stem blight