• Apple collar rot

  January 1, 1970

  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 [...] produced in the sporangia. For germination on above-ground plant parts, leaf wetness is required. Dispersal by wind and rain causes the pathogen to be returned

• Onion thrips

  January 1, 1970

  General The onion thrips (Thrips tabaci) is distributed throughout the world. It is found outdoors on many plants and particularly damaging on onions, [...] are inserted into the plant tissue with a saw-like ovipositor. Larvae are light to yellowish green in colour, with a large head and bright red eyes. The colour [...] the plant is reduced by loss of chlorophyll. When infestations become serious the leaves themselves can shrivel. Onion thrips (Thrips tabaci) is found mostly

• Wheat bunt

  January 1, 1970

  on all spikelets, showing the bunt (smut spore) they contain, which is larger than a normal kernel. The bunt balls are grey-brown. They rupture at harvest [...] contaminate healthy kernels, which in turn become a source of disease in the next season. Infection is strongly correlated to temperature and precipitation [...] Triticum laevis . Since Triticum controversa mostly attacks the 2-3 leaf stage, this is less effective for this fungus Prevent plant diseases by optimizing

• Glasshouse potato aphid

  January 1, 1970

  with a brown head, a dark thorax and a dark abdomen that has pale to dark transverse bands. The body shape is similar to wingless females, but is 2.0-3 [...] pepper it secretes a toxic substance, which leads to deformations in the growing tip of the plant. Precisely where the plant is pierced is unimportant. The [...] aphid Aphids have a complex life cycle, with both winged and wingless forms of adults and a great variety in colour. When reproduction is asexual, the young

• Fusarium head blight or scab

  January 1, 1970

  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 [...] mycelium cells) or mycelium. Survival is also possible on seed, greenhouse structures, tools and machinery. Primary infection is either seed-borne or takes place [...] symptoms Fusarium fungi cause vascular wilt, root rot, foot and stem rot, leaf lesions, fruit rot, fusarium head blight in cereals, such as wheat (fusarium

• Phytophthora blight

  January 1, 1970

  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 [...] 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

• Verticillium wilt

  January 1, 1970

  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 [...] occur on the stem. In tomato, sometimes V-shaped lesions are formed on the leaf, between the veins. 'Early dying' disease of potato only occurs as premature

• Black leg of seedlings

  January 1, 1970

  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

• Damping-off

  January 1, 1970

  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

• Flies

  January 1, 1970

  has recently developed into a major pest on soft fruits in Europe and North America. Sciarid flies and shore flies are mainly a problem in greenhouses. Their [...] prefer moist substrates that is rich in organic matter. Although they cause little direct damage to plants, they are often a problem due to their large number [...] of the flies. Direct damage is the immediate result of larvae feeding on root hairs and tender roots as well as stem and leaf tissue and fruits. The lesions