• Bacterial spot

  green fruits. The specks grow into brown spots that look like scab. These spots may be surrounded by a halo. In pepper, the spots on the leaves are also [...] vesicatoria in tomato causes small, water-soaked spots on leaves which are first round and become more angular as they grow. The centre of the lesions may [...] Xanthomonas vesicatoria survives on volunteer tomato plants in the field and on diseased plant debris. The bacteria are also seed-transmitted. Disease development

• Apple collar rot

  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 [...] n of the roots. On the foot, dark brown lesions with sharp borders occur. Above the graft and on leaves, dark brown, irregular lesions occur. In strawberry [...] optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil in different stages: as oospores (sexual overwintering

• Grapevine powdery mildew

  early berry development. As the season concludes, the fungus forms chasmothecia to ensure its survival through the winter. Given the polycyclic nature, preventive [...] Symptoms of grapevine powdery mildew vary according to the phenological growth stage and the severity of the infection. Early signs manifest as chlorotic (pale [...] develop into the characteristic white to grey powdery mycelium. As the infection intensifies, affected leaves suffer a marked reduction in photosynthetic

• Black sigatoka disease

  them, so the spores cannot be discharged from the lower leaves in the stack Use under-canopy (drip) irrigation to reduce splash dispersal Lower the humidity [...] leaves of about one month old. The symptoms run parallel to the veins. Within a few days, the spots become a few centimetres in size and turn brown with light [...] enlarge further and the tissue around the lesions turns yellow and dies. Lesions merge and the whole leaf turns brown and ultimately dies. In cases of severe

• Phytophthora blight

  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 [...] 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 [...] optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil in different stages: as oospores (sexual overwintering

• Pea blight, leaf and pod spot

  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 [...] ) causes foot rot in peas, whereas Ascochyta pisi does occur sometimes at the stem base but is not part of the foot rot syndrome in peas. Infected seeds [...] 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

• Leaf stripe

  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. [...] 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

• Downy mildew of Cucurbits

  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 [...] 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 [...] formed, structures in which zoospores are produced. However, in downy mildews, sporangia often germinate directly and the germ tubes infect the plants either

• 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

• 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