• Southern blight

  lesions on the stem. As the damage progresses, it causes darkening and rotting of the stem, resulting in the destruction of the cortex and the main root [...] darkening and rotting of the stem, resulting in the destruction of the cortex and the main root. As a consequence, leaves higher up in the plant start yellowing [...] plants. The sclerotia can survive in the soil for a minimum of a year. The telemorphic phase corresponds to the basidiomycetes Athelia rolfsii, but this is rarely

• Fusarium head blight or scab

  density. The foot of the plant is infected, either because the seedling was infected or by direct infection of the foot by overwintering inoculum. On the infected [...] takes 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. Gibberella zeae (Fusarium [...] spread the disease. Gibberella zeae (Fusarium graminearum ) primarily infects the older, lower leaves. The spores are dispersed upwards to the ears by

• Black leg of seedlings

  older plants, the leaves lose their turgor or the leaf tips turn yellow, for example in flower bulbs. At first, the plants recover during the night, but later [...] later the plants wilt irreversibly. In potted plants the flower buds fall off. The side roots rot and very little of the root system survives. On the border [...] and soil or substrate the plant turns brown. A typical symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger

• Leaf stripe

  Eventually this leads to the death of the leaf. The leaf splits at the end which makes it look shredded. This is typical for this disease. Infected plants [...] 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.

• Downy mildew of Cucurbits

  and the germ tubes infect the plants either through the stomata or directly by penetrating the cuticula. For germination free water is required. For most [...] 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 required [...] Inside the plant, the pathogens produce haustoria, small organs with which the pathogen can take up nutrients from the living plant cells. The pathogens

• Bacterial soft rot, bacterial stem rot

  wilt at the time of first harvest or after that. The pith disintegrates and the stem becomes hollow. Because of the bacterial growth in the pith, the stem [...] stem seems wet and slimy. Above or below the hollow stem the vascular tissue keeps its normal colour. On the fruits, lesions first are small and sunken, w [...] plants or in the soil in low densities. It has also been found in the gut of insects, possibly spreading from decaying vegetation to the growing crop that

• Root and crown rot of strawberry

  s clavispora in the case of root and crown rot (of strawberry), first found in The Netherlands, and Pestalotiopsis longisetula in the case of leaf spots [...] strawberry Not much is known about the life cycle. The fungus produces ascospores and conidia, but their role in the epidemic has not yet been established [...] spot of strawberry and fruit rot reported mainly from Brazil. The genus is quite complex, so the taxonomy may change. Pestalotiopsis clavispora is also called

• Apple collar rot

  from the root to the foot, but direct infection of the foot also occurs. Exudates leaking from growing root tips promote germination and attract the zoospores [...] wind and rain causes the pathogen to be returned to the soil from infected plants. Dispersal in the soil happens via water, since the zoospores can readily [...] This explains why the disease spreads more rapidly when the water content of the soil or substrate is higher than normal or optimal for crop growth. How

• Grape downy mildew

  humidity), the disease is often well-established before it can be visually detected in the field. Leaf symptoms Yellowish to light-green oil spots on the upper [...] are dispersed via rain splash to the canopy, where they encyst and penetrate the host through stomata. Once inside the host tissue, hyphae extend inter [...] mesophyll cells. The latent period (the time from infection to visible symptoms) ranges from 4 to 21 days, depending on temperature; the most rapid development

• Wheat bunt

  sporidia infect the wheat seedlings even before emergence and the fungi grow inside the plants to the growing tip. The fungi grow between the plant cells and [...] heads. The glumes are opened either on some or on all spikelets, showing the bunt (smut spore) they contain, which is larger than a normal kernel. The bunt [...] sporidium. Two mating types are distinguished. The filiform basidiospores fuse in the middle with a basidiospore of the other mating type so that H-shaped structures