• Gummy stem blight

  January 1, 1970

  most important symptom is internal fruit rot, which can only be recognized from the outside by the small narrowing of the tip of the mature fruits. The symptoms [...] cropping and between consecutive cucumber crops: Remove all pots and plant parts from previous crop that may serve as inoculum source for the new crop prevent

• Downy mildew of Cucurbits

  January 1, 1970

  nutrients from the living plant cells. The pathogens continue to grow inside the leaves and after a while new spore-bearing structures are protruding from the [...] turns grey-brown. This is actually the sporulation of the pathogens extruding from the stomata. Life cycle and appearance of Downy mildew Pathogens causing [...] Oomycetes and related to Pythium and Phytophthora. They survive as oospores. From these oospores or surviving mycelium sporangia are formed, structures in

• Phytophthora blight

  January 1, 1970

  water. Infection is usually from the root to the foot, but direct infection of the foot also occurs. Exudates leaking from growing root tips promote g [...] cells which are resistant to desiccation) or mycelium. Zoospores are formed from the overwintering structures which infect the host. Zoospores are spores [...] Dispersal is by 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

• Bacterial canker of tomato

  January 1, 1970

  Europe, which means that strong efforts are used to prevent the bacterium from entering. When the occasional infection is found, strict measures are taken [...] Potato growers lose their entire crop of the affected field and potatoes from other fields on the farm, are labelled as ‘suspect’ that year. On the infected [...] lavibacter infection, but other than that the disease is difficult to distinguish from wilting caused by other pathogens. On potato tubers, first discolouration

• Crazy roots, hairy roots, crown gall

  January 1, 1970

  have been isolated from crazy roots. This disease seems to be caused by a change in the hormonal system of the plant resulting from the Rhizobium infection [...] bacteria survive in the soil, but it is possible that first infection is from the propagation material. Infection also takes place via wounds. After infection

• Cut flowers

  January 1, 1970

  originates from Central and South America. It is a bulb plant from the large family of the Amaryllidaceae, the narcissus family. The Hippeastrum comes from America [...] America, from northern Argentina to Mexico and the Caribbean. Is grown from a bulb as a cut flower or sold as a pot plant. Freesia : The freesia is a herbaceous [...] perennial flowering plant from the Iridaceae family. The cultivated freesias are graceful funnel-shaped hybrids, descended from a number of freesias. Lily

• Foot rot of cereals

  January 1, 1970

  root rot. Symptomless infections can also occur. Foot rot becomes obvious from late stem extension onwards. It results in dark-brown staining of the lower [...] plant physiology. Typically, the lifecycle begins with the release of spores from infected plant debris or soil. These spores, known as conidia, are spread [...] cereals Avoid following maize with wheat in rotations Bury soil-surface residue from previous crops, since this is the major inoculum source, especially after

• Pierce's disease of grapevine

  January 1, 1970

  browning of leaves 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 [...] high numbers are found in leaves and fruits. The bacteria are transferred from plant to plant by all kinds of xylem-feeding insects. Well known, but certainly [...] presence increases the risk of infection in cultivated crops. The spread from one host plant species to another is still under investigation and seems

• Fusarium head blight or scab

  January 1, 1970

  chlamydospores and ascospores in crop residues. Primary infection is from this inoculum or from infected seed. Infected seed doesn’t germinate well and seedlings [...] the root tip or in small wounds, for example where lateral roots branch off from the tap root. Gibberella zeae (Fusarium graminearum) overwinters as chla

• Root and crown rot of strawberry

  January 1, 1970

  leaf spots, such as leaf spot of strawberry and fruit rot reported mainly from Brazil. The genus is quite complex, so the taxonomy may change. Pestalotiopsis [...] is mostly found in plants that have been weakened by some form of stress, from underfertilization to water stress (either too much or too little water)