• Downy mildew of Cucurbits

  leaves but occasionally also stems and fruits. They cause lesions on the upper leaf surface, bordered by the veins, which are first yellow and then turn brown [...] around 15 o C and the closer the temperature is to this, the shorter the leaf wetness period that is required. Inside the plant, the pathogens produce [...] from the stomata. Because there are more stomata on the underside of the leaf, this is where most fluffy symptoms are found. How to prevent Downey mildew

• Bacterial spot

  small to start with and slightly raised from the leaf surface. They occur on the abaxial (underside of) leaf surfaces and may enlarge into dark brown lesions [...] General Xanthomonas vesicatoria is a bacterium that causes bacterial leaf spot on peppers and tomatoes. Damage symptoms Xanthomonas vesicatoria in tomato

• Broad mite

  that disturb local growth. Leaf feeding is mainly concentrated on the underside near the leaf stalk, which tends to cause the leaf to turn brown and curl up [...] stand out as a green pattern against the brown leaf tissue. Brown, corky patches can appear on the leaf stalks and main stems. The growing tips of affected [...] Polyphagotarsonemus latus ) lay their eggs mainly on the underside of the leaf or on the fruit surface. The elongated, oval eggs are firmly attached to

• Apple scab

  between 18 and 24 °C, only 9 hours of leaf wetness is required, at lower temperatures this increases to 12-28 hours of leaf wetness for successful infection [...] cultivars Prune to ensure good air circulation, this decreases the duration of leaf wetness Shred fallen leaves in autumn/winter Spray fallen leaves with urea

• Root rot of carrot

  increase in number and size until they merge, after which whole sections of the leaf will die off. The fungus appears to prefer older tissue. In the field, the [...] dauci . Cercospora prefers younger leaves. A. dauci starts mainly along the leaf edges. Rhexocercosporidium infection can cause loss of seedlings. The subsurface [...] remain green. During humid spells the surviving plants exhibit by necrotic leaf spots Life cycle and appearance of Root rot of carrots The fungus of R. carotae

• Tea

  cambod type). Tea is a dried leaf of a bush and contains theine. Tea beverage produced in freshly boiled water having leaves and leaf buds of the tea plant.

• Pierce's disease of grapevine

  symptoms Grapevines: Primary infection of leaves results in leaf scorch. Part of a green leaf suddenly dies and turns brown with adjacent tissue turning [...] diseases such as Pierce's disease of grapevines, phony peach disease, plum leaf scald, citrus variegated chlorosis and quick decline syndrome. Recently, [...] turning yellow or red. This desiccation spreads and the whole leaf may shrivel and drop off. Infected stems show irregular maturation and patches of brown and

• Root and crown rot of strawberry

  The Netherlands, and Pestalotiopsis longisetula in the case of leaf spots, such as leaf spot of strawberry and fruit rot reported mainly from Brazil. The

• Grapevine powdery mildew

  secondary infections, such as Botrytis bunch rot. Leaf symptoms Pale green to yellowish spots on the upper leaf surface Development of white to grey, powdery [...] fungal growth Powdery coating may also appear on the underside of leaves Leaf curling, distortion, and brittleness as infection progresses Reduced pho

• Tobacco whitefly

  are mobile, whereas the rest of the larvae stadia remain flattened on the leaf. The fourth larva stadium develops into a yellow, almost circular so called [...] scattered over the entire plant where they deposit their eggs. This is why on one leaf all different developmental stages can be found together. When shaking infested [...] which growth is retarded. In full sunlight, leaves can wilt and fall. Such leaf damage can in turn influence the development of fruit and lead to a reduction