• Black leg of seedlings

  stripping of the skin from the root cortex with a finger nail. Life cycle and appearance of Black leg of seedlings Pythium belongs to the Oomycetes, a separate [...] and very little of the root system survives. On the border between air and soil or substrate the plant turns brown. A typical symptom of a Pythium infection [...] conditions, especially dehydration. Germination of the oospores is stimulated by exudates from roots of a susceptible host nearby. The oospores germinate and form

• Black rot of carrots

  appearance of Black rot of carrots Black rot of carrots ( Alternaria radicina ) is a seed-transferred carrot disease. The seeds are the main source of primary [...] infection of the leaves. Survival can be several years, in the case of black rot of carrots ( Alternaria radicina ) up to 8 years. Damage symptoms Black rot [...] source of infection. Especially wheat and barley reduce the number of surviving conidia in the soil. Use resistant cultivars against black rot of carrots

• Black root rot of cucurbits

  also cause black fruit rot. Life cycle and appearance of Black root rot of cucurbits Phomopsis sclerotioides survives in the soil and is a strong saprophytic [...] sclerotioides is a plant pathogen infecting cucurbits, causing black root rot of cucurbits. Damage symptoms Phomopsis sclerotioides causes grey-black spots with [...] like black stripes. The disease is usually restricted to a few of the roots but in severe cases all roots may be infected. At the final stage of the disease

• Black sigatoka disease

  brown and ultimately dies. In cases of severe infection leaves may die within a few weeks. Because of the lack of leaf tissues, fruit maturity is hampered [...] lla fijiensis also known as black sigatoka, is an ascomycete fungus that causes leaf-spot of banana. Damage symptoms Black sigatoka (Mycosphaerella fijiensis [...] spots or streaks on leaves of about one month old. The symptoms run parallel to the veins. Within a few days, the spots become a few centimetres in size and

• Blight of pepper

  die and brown-black lesions occur on the larger roots. Plants wilt and the crown leaves drop off. Life cycle and appearance of Blight of pepper Phytophthora [...] and fruit rot of peppers and other important commercial crops. Damage symptoms Phytophthora causes root rot, seedling damping off and rot of stems, bulbs [...] plant surface and new sporangiophores (structures containing sporangia, a type of spores) with sporangia are formed that protrude through the stomata. Secondary

• Root rot of carrot

  starts with small black spots over the entire surface of the carrot. These spots gradually change into larger dark brown to black lesions of various shapes [...] only host plant of the fungus. How to prevent root rot of carrot Studies have shown that 3several key factors influencing the occurrence of blemishes and [...] Additionally a strong foliage and uniform stand allow better functioning of mechanical harvesters, leading to less mechanical damage of the carrots.

• Loose smut of barley

  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. [...] 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 [...] hordei affects barley and can destroy a large proportion of the crop. It is also known as barley smut, or loose smut of barley. Damage symptoms Infection by

• Loose smut of wheat

  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. [...] 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 [...] cycle and appearance of Loose smut of wheat The seeds are infected during flowering and the infected seeds are the primary source of inoculum in the next

• Downy mildew of Cucurbits

  On the underside of the leave fluffy growth appears which is first white and later turns grey-brown. This is actually the sporulation of the pathogens extruding [...] leaves and after a while new spore-bearing structures are protruding from the stomata. Because there are more stomata on the underside of the leaf, this [...] prevent Downey mildew Choose resistant cultivars Use a wide crop rotation with non-host crops Prevent a humid microclimate. Achieve this by lowering crop

• Pierce's disease of grapevine

  olive. Damage symptoms Grapevines: Primary infection of leaves results in leaf scorch. Part of a green leaf suddenly dies and turns brown with adjacent [...] occur on the underside of the leaves. These lesions start out in a light-brown colour, turning to dark-brown or necrosis. Fruits of infected trees are much [...] General Xylella fastidiosa is a gram-negative bacterium which is limited to xylem tissue. It has many hosts, many of which show minor or no symptoms. More