• Leaf stripe

  January 1, 1970

  graminea is monocyclic, which means there is only one disease cycle during the cropping season. The fungus is seed-borne and this systemic infection is the [...] primary infection. The fungus spreads from the seed into the seedling. Conidia are produced on the infected leaves when humidity is high and wind-dispersed [...] formed at the base of the leaf and the leaf sheath. They gradually extend and become brown and chlorotic and may merge. Eventually this leads to the death

• Southern blight

  January 1, 1970

  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 [...] southern blight is a disease caused by the fungus Athelia (Sclerotium) rolfsii . It is an important plant pathogen that inhabits the soil, and is responsible [...] 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

• Powdery mildew

  January 1, 1970

  infected. In pepper, the fluffy colonies occur mostly on the underside of the leaf, because the fungus infects the plant by entering through the stomata and there [...] Rosaceae , the fungus causing powdery mildew is extremely sensitive to water and ‘hides’ on the underside of the leaves. Therefore, this is where the colonies [...] on the underside of the leaf. On the upper side, yellow spots are noticeable. In case of a severe epidemic, the fluffy colonies also appear on the upper

• Root and crown rot of strawberry

  January 1, 1970

  rot reported mainly from Brazil. The genus is quite complex, so the taxonomy may change. Pestalotiopsis clavispora is also called Neopestalotiopsis clavispora [...] strawberry. Plant development is slow, growth is retarded and rooting is poor. Transplants look weak and may die. It is hard to visually distinguish between [...] rot of 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

• Fusarium wilt

  January 1, 1970

  Fusarium 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 [...] upwards on the outside of the plant. Most Fusarium species only make asexual spores. Some also produce ascospores. The Fusarium oxysporum life cycle, is similar

• Black root rot of cucurbits

  January 1, 1970

  survive adverse conditions for years in the soil, but little else is known about the life cycle. The fungus is dispersed by water, air and soil particles [...] 10 °C the lesions are light-brown. The lesions can be enclosed by pseudostromata: dark coloured tissue that looks like black stripes. The disease is usually [...] 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

• Pea blight, leaf and pod spot

  January 1, 1970

  surrounded by a dark brown to red-brown border. The first infection is often on the primary leaves. The fungus is seed borne and thus also causes post- and [...] transmitted on the outside of the seed coat and cause primary infection. The conidia germinate and infect through the stomata or directly through the cuticle [...] on leaves, stems and pods of peas. The spots on leaves and pods are round, on the stems they are more elongated. The lesions are light brown, sunken and

• Phytophthora blight

  January 1, 1970

  fungal growth on the leaves. The centre is grey-brown with a light-green edge. On the stem, elongated brown lesions occur, usually circling the stem. On potato [...] leaf wetness is required. Dispersal is by wind and rain causes the pathogen to be returned to the soil from infected plants. Dispersal in the soil happens [...] 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

• Blight of pepper

  January 1, 1970

  leaf wetness is required. Dispersal is by wind and rain causes the pathogen to be returned to the soil from infected plants. Dispersal in the soil happens [...] 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 [...] water, since the zoospores can readily move through water. This explains why the disease spreads more rapidly when the water content of the soil or substrate

• Pierce's disease of grapevine

  January 1, 1970

  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 [...] plums): In peach, the canopy of infected plants is compact and umbrella-like due to the shorter internodes. The foliage is denser and the leaves are a darker [...] 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