Root rot of carrot

epidermal cell, and then intracellular and intercellular mycelium. Conidia buried in nonsterile soil remained viable at 0°C and 3°C for 12 months, at 6°C for [...] air. The fungus develops at temperatures ranging from -3°C to 25°C, with an optimum around 18°C. Lesions are dark brown to black, moist, mostly circular [...] ridium carotae develops at temperatures ranging from -3°C to 25°C, with an optimum around 18°C; temperature affects both host defense processes and fungal

Powdery mildew

from which the fungus penetrates the plant cell and takes up nutrients from the epidermal layer of plant cells. Most of the fungus remains on the outside [...] Leveillula ) are all biotrophic fungi, meaning they feed on living plant cells and barely survive in the absence of a living crop. They survive as ascospores [...] germination. In general, the development rate of the epidemic is fastest at 18-25 °C. High relative humidity (RH) promotes germination of spores but inhibits spore

Cottony soft rot

ground. Sclerotia germinate at temperatures between 4 and 26 °C with an optimum between 13 and 15 °C. Germination and infection mostly take place at high soil [...] sclerotia. The fungus grows quite rapidly inside the plant and kills the host cells. On the infected plant tissue white, fluffy mycelium occurs with new dark

Spider mites and other mites

on the underside of leaves where they pierce the cells and suck out the contents. The empty dead cells become yellow, and in many plants the damage can [...] species can rapidly infest greenhouse and field crops, feeding on plant cells and causing leaf discoloration, reduced photosynthesis and lower yields. [...] on the upper surface of leaves as small yellow dots. The destruction of cells results in reduced photosynthesis, increased transpiration and reduced plant

Fusarium head blight or scab

between 4 and 35 °C, with an optimum between 25 and 28 °C. Germination only occurs at relative humidity (RH) above 80%. Warm (25-30 °C) and humid (RH above [...] crop residues of infected plants as chlamydospores (thick walled mycelium cells) or mycelium. Survival is also possible on seed, greenhouse structures, tools

Two-spotted spider mite

on the underside of leaves where they pierce the cells and suck out the contents. The empty dead cells become yellow, and in many plants the damage can [...] on the upper surface of leaves as small yellow dots. The destruction of cells results in reduced photosynthesis, increased transpiration and reduced plant [...] plant growth. As damage increases, whole leaves turn yellow, and as more cell sap is removed, the leaf, and eventually the whole plant, may die. In tomatoes

Downy mildew of Cucurbits

is required. For most downy mildews, the optimum temperature is around 15 o C and the closer the temperature is to this, the shorter the leaf wetness period [...] organs with which the pathogen can take up nutrients from the living plant cells. The pathogens continue to grow inside the leaves and after a while new

Grape downy mildew

mesophyll cells. Symptoms appear 4-21 days after infection, depending on temperature, with the shortest period on young leaves at 19-24°C. Management [...] grape buds and canes. In spring, oospores germinate when temperatures reach 10°C and soils are wet, forming macrosporangia that release zoospores within 24

Wheat bunt

grow inside the plants to the growing tip. The fungi grow between the plant cells and eventually inside the kernels. When that happens, the fungal mycelium [...] with maximum disease incidence at an average temperature of around 6 to 7 °C during that period. Soil moisture between field capacity and permanent wilting [...] Sowing winter crops early in the fall when temperatures are still above 15°C at the critical first 11 days reduces the risk of infection by Triticum tritici

Pea blight, leaf and pod spot

On the lesions, pycnidia are formed from which orange-red masses of two-celled conidia are exuded. Secondary infection is by splash dispersal of these [...] sexual stage. Ascochyta fungi develop most rapidly at temperatures below 20 °C and the spores require water for dispersal. How to prevent Pea blight, leaf