• Trianum effectively controls Pythium in cucumber

  vigour and is suited to exposure levels above 180 micromol. But the variety has a slightly weaker root base than other varieties. ‘This is another reason [...] Phythium at a very acceptable level. Treatment with Trianum is easy, requires very little labour, and is reasonably priced.’ [...] explained Kees Hendriks. Together with Stefan Wubben, Kees Hendriks runs a farm covering over six hectares along Hoefslag road in the Dutch village of Pijnacker

• Crazy roots, hairy roots, crown gall

  source of infection by Rhizobium rhizogenes has not yet been defined. The assumption is that the bacteria survive in the soil, but it is possible that first [...] dispersed by rain and wind and by humans and tools. Until now, no bacteria have been isolated from crazy roots. This disease seems to be caused by a change [...] underground plant parts and on the crown. Furthermore, infection is characterized by excessive root growth (crazy roots). In greenhouse vegetables, the

• Root and crown rot of strawberry

  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 [...] reported mainly from Brazil. The genus is quite complex, so the taxonomy may change. Pestalotiopsis clavispora is also called Neopestalotiopsis clavispora [...] not yet been established. Pestalotiopsis clavispora is mostly found in plants that have been weakened by some form of stress, from underfertilization to water

• Downy mildew of Cucurbits

  stomata or directly by penetrating the cuticula. For germination free water is required. For most downy mildews, the optimum temperature is around 15 o C and [...] surface, bordered by the veins, which are first yellow and then turn brown. On the underside of the leave fluffy growth appears which is first white and [...] 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

• Phytophthora blight

  infection is either by germinating sporangia or by zoospores produced in the sporangia. For germination on above-ground plant parts, leaf wetness is required [...] required. 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 [...] fast drying and wound healing, by allowing air circulation Disinfect recirculating nutrient solutions Prevent plant diseases by optimizing plant potential

• Bacterial canker of tomato

  primary infection is mostly from infected propagation material. It spreads to other seedlings by touching the plants in greenhouse crops and by water in field [...] lavibacter infection, but other than that the disease is difficult to distinguish from wilting caused by other pathogens. On potato tubers, first discolouration [...] tubers. This discolouration is round, hence the name ring rot. Life cycle and appearance of Bacterial canker of tomato Clavibacter is seed-borne and tuber-borne

• Glume blotch

  above freezing when water is available. Conidia require a minimum of 5 °C for germination. Primary infection is mostly by ascospores or conidia on the [...] secondary infection by splash dispersal. Splashing rain water helps the fungus to reach the upper leaves and ears. Seed infection is enhanced by wet weather [...] leaves are infected and frequent rain is expected Be aware that in a crop with dense foliage, splash dispersal is more efficient so the disease will spread

• Gummy stem blight

  In cucumber, the 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 [...] wounds and by the infected leaves through the petioles. Fruits are infected through the flowers. The newly produced ascospores are dispersed by air and the [...] General Mycosphaerella cucumis (Didymella bryoniae) is a fungal plant pathogen that causes gummy stem blight. Damage symptoms Mycosphaerella cucumis in

• Apple scab

  become grey and fluffy. The lesions caused by ascospores are more restricted, whereas the lesions caused by conidia extend faster and may merge. Infected [...] . The plants’ defence mechanism is to produce corky rings around the lesions to prevent further invasion of tissue by the fungus. Late fruit infection [...] sed to the fruit trees and will germinate if free water is available. They infect the plant by direct penetration of the cuticula and then grow between

• Angular leaf spot

  often limited by the small veins. The distinctive feature is the way the lesions look when using different light sources: when reflected light is used, the [...] General Xanthomonas fragariae is a leaf spot disease found in strawberry. Damage symptoms Xanthomonas fragariae initially causes small, water-soaked lesions [...] the lesions look dark green, but when transmitted light is used, they are translucent. When conditions are humid, a viscous bacterial exudate forms on the