Phytophthora blight

borders and white fluffy fungal growth on the leaves. The centre is grey-brown with a light-green edge. On the stem, elongated brown lesions occur, usually [...] s containing sporangia, a type of spores) with sporangia are formed that protrude through the stomata. Secondary infection is either by germinating sporangia [...] sporangia. For germination on above-ground plant parts, leaf wetness is required. Dispersal is by wind and rain causes the pathogen to be returned to the soil

Damping-off

substrate the plant turns brown. A typical symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger nail. Life cycle [...] General Pythium is considered a ‘weak pathogen’, meaning that it can usually only affect plants that are in a sub-optimal condition or suffer from stress [...] Damping-off Pythium belongs to the Oomycetes, a separate group of microorganisms and is therefore not a real fungus. It survives as oospores, resting spores

Powdery mildew

General Powdery mildew is a fungal disease that is caused by many different species of fungi such as Erysiphe, Podosphaera, Oïdium, Leveillula. Damage [...] fungus causing powdery mildew is extremely sensitive to water and ‘hides’ on the underside of the leaves. Therefore, this is where the colonies mostly occur [...] epidemics and spore dispersal by rain is negligible, since spores explode when in contact with water for no more than a few hours. Powdery mildew spores, either

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 [...] packing materials etc. The fungus may be transferred on seed but this is not considered a main source of infection. Optimum conditions for this fungus are [...] above 32 °C and dry conditions. In field crops in temperate regions it is therefore not a problem. How to prevent Charcoal rot Plant in fields with no history

Fusarium wilt

General Fusarium is a group of soil-borne fungi with many different species. Fusarium is widespread and can infect a range of host crops. Many species [...] pathogenic on a limited number of crops. Even within one crop, different formae speciales may occur and cause different symptoms. Fusarium oxysporum is the only [...] mycelium cells) or mycelium. Survival is also possible on seed, greenhouse structures, tools and machinery. Primary infection is either seed-borne or takes place

Crazy roots, hairy roots, crown gall

yet been defined. The assumption is that the bacteria survive in the soil, but it is possible that first infection is from the propagation material. Infection [...] 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

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 [...] s containing sporangia, a type of spores) with sporangia are formed, that protrude through the stomata. Secondary infection is either by germinating sporangia [...] range. Damage symptoms Phytophthora cactorum causes seedling damping off, a reduced root system and black discolouration of the roots. On the foot, dark

Black leg of seedlings

substrate the plant turns brown. A typical symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger nail. Life cycle [...] General Pythium is considered a ‘weak pathogen’, meaning that it can usually only affect plants that are in a sub-optimal condition or suffer from stress [...] of seedlings Pythium belongs to the Oomycetes, a separate group of microorganisms and is therefore not a real fungus. It survives as oospores, resting spores

Loose smut of wheat

smut of wheat General Ustilago nuda f.sp. tritici is a basidiomyceteous fungus that affects wheat. It is also known as loose wheat smut, or loose smut of [...] 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 smut spores. Solution [...] within a day and infect the inner tissues of the newly infected seed. During maturation of the seed, the mycelium becomes thick-walled and swollen as a dormant

Cottony soft rot

as cottony soft root, is a plant pathogenic fungus. It has a very wide range of host plants. Damage symptoms The first symptoms of a cottony soft root ( [...] seeds and tubers, thereby creating a source of infection for the next crop. The dispersal to neighbouring plants is by mycelial growth. How to prevent [...] Germination and infection mostly take place at high soil water content over a prolonged period of time. The sclerotia germinate directly and form mycelium