• Early blight

  Alternaria occurs at temperatures from 2-4 °C up to 28-30 °C (optimum temperatures lie between 15 and 28 °C) and at a relative humidity (RH) of over 90% or when [...] during harvest (in potato and carrot). Post-harvest storage at 0-1 o C. A. brassicae and A. brassicicola : adjust the sowing date to avoid conditions conducive [...] occur on leaves. Those spots then turn into dark brown angular lesions with a yellow halo restricted by leaf veins. Lesions can easily rupture. Other symptoms

• Pierce's disease of grapevine

  spreads over the leaf from the margin and is marked by a chlorotic band. In the beginning, only a few leaves per branch are showing symptoms, but later [...] Use hot water treatment of dormant cuttings (20 minutes at 50 °C or 180 minutes at 45 °C) Prune diseased branches or whole trees to remove inoculum sources [...] General Xylella fastidiosa is a gram-negative bacterium which is limited to xylem tissue. It has many hosts, many of which show minor or no symptoms. More

• Black sigatoka disease

  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 grey centres [...] but infection takes a minimum of two or three days under optimal conditions (humidity close to saturation and temperature above 20 °C). How to prevent Black [...] brown and ultimately dies. In cases of severe infection leaves may die within a few weeks. Because of the lack of leaf tissues, fruit maturity is hampered

• Grapevine powdery mildew

  Grapevine powdery mildew (Erysiphe necator) is a widespread fungal disease that poses a serious threat to commercial viticulture worldwide. The pathogen [...] it does not require free water (such as rain or dew) to infect, making it a persistent threat throughout the entire growing season. Early detection and [...] grey powdery mycelium. As the infection intensifies, affected leaves suffer a marked reduction in photosynthetic capacity, while shoots and flowers exhibit

• Pea blight, leaf and pod spot

  General Ascochyta pisi is a fungal plant pathogen that causes A scochyta blight on pea (leaf blight or pea blight) and lesions of stems, leaves, and pods [...] below 20 °C and the spores require water for dispersal. How to prevent Pea blight, leaf and pod spot Grow peas in arid regions Use clean seed Use a minimum [...] are more elongated. The lesions are light brown, sunken and surrounded by a dark brown to red-brown border. The first infection is often on the primary

• Crazy roots, hairy roots, crown gall

  seems to be 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 causes a genetic change in the plant. How to prevent Crazy roots, hairy roots, crown gall Use clean propagation material Use a strict hygiene protocol [...] established inside root nodules of legumes. Additionally, pathogenic Agrobacterium s pecies have recently been assigned to the genus Rhizobium . These pathogenic

• Bacterial canker of tomato

  disinfect tools and greenhouse structures Use a crop rotation in field crops of at least two years and alternate with a non-host crop Apply deep-ploughing to stimulate [...] General Clavibacter is a quarantine organism in Europe, which means that strong efforts are used to prevent the bacterium from entering. When the occasional [...] entirely or, if the crop is old, only the plants in the infected area, with a substantial buffer zone. Replanting can only take place after thorough disinfection

• Charcoal rot

  General Macrophomina phaseolina is a common soil fungus in warmer regions, causing charcoal rot. It has a very wide range of host crops, many of which [...] seed but this is not considered a main source of infection. Optimum conditions for this fungus are temperatures above 32 °C and dry conditions. In field crops [...] crops in temperate regions it is therefore not a problem. How to prevent Charcoal rot Plant in fields with no history of the disease Use disease-free planting

• Verticillium wilt

  Verticillium albo-atrum is 21 °C and growth stops above 30 °C, whereas Verticillium dahliae has an optimum temperature around 25-27 °C. How to prevent Verticillium [...] wilt Start with clean soil or substrate by heating it at a temperature if at least 65 o C for a minimum of 30 minutes Use clean seed, tubers or cuttings [...] may occur only in parts of the plant. Cutting the stalk horizontally reveals a slight discolouration of the vessels, brown or greenish, but much less distinct

• Apple collar rot

  General Phytophthora cactorum is a plant pathogen that causes root rot, rhizome rot of strawberry, apple rot, apple collar rot and crown rot. It has an [...] range. Damage symptoms Phytophthora cactorum causes seedling damping off, a reduced root system and black discolouration of the roots. On the foot, dark [...] strictly speaking not fungi. They thrive at soil temperatures between 15 and 23 °C and higher water content than is optimal for crop growth. Phytophthora overwinters