Phytophthora blight

from the root to the foot, but direct infection of the foot also occurs. Exudates leaking from growing root tips promote germination and attract the zoospores [...] fungal growth on the leaves. The centre is grey-brown with a light-green edge. On the stem, elongated brown lesions occur, usually circling the stem. On potato [...] through the skin. The Great Famine was a period of mass starvation caused by this disease which ravaged potato crops throughout Europe during the 1840s.

Cottony soft rot

infects the stem base and the roots, whereas the ascospores infect the above-ground plant parts. In greenhouses, usually only mycelium is produced by the germinating [...] range of host plants. Damage symptoms The first symptoms of a cottony soft root ( Sclerotinia sclerotiorum ) infection are water-soaked lesions at the stem [...] germinating sclerotia. The fungus grows quite rapidly inside the plant and kills the host cells. On the infected plant tissue white, fluffy mycelium occurs

Bacterial soft rot, bacterial stem rot

wilt at the time of first harvest or after that. The pith disintegrates and the stem becomes hollow. Because of the bacterial growth in the pith, the stem [...] plants or in the soil in low densities. It has also been found in the gut of insects, possibly spreading from decaying vegetation to the growing crop that [...] stem seems wet and slimy. Above or below the hollow stem the vascular tissue keeps its normal colour. On the fruits, lesions first are small and sunken, w

Bacterial spot

as they grow. The centre of the lesions may fall out as they become drier. Under humid conditions, the spots may merge with lesions on the petioles and [...] plants and crop debris Avoid waste piles in the vicinity of the greenhouse or field Resistant cultivars of pepper are available and should be used Prevent [...] and appearance of Bacterial spot Xanthomonas vesicatoria survives on volunteer tomato plants in the field and on diseased plant debris. The bacteria are

Bean seed fly

flies lay eggs near the base of bean plants, and upon hatching, the larvae burrow into the soil and feed on the seeds and roots of young plants. Larvae [...] discolored. Thirdly, search for the presence of larvae. Small, white maggots near the base of affected bean plants are a clear sign of bean seed fly infestation [...] significant damage. Presence of larvae: Small, white maggots near the base of affected bean plants. These larvae are a clear indicator of bean seed fly infestation

Onion fly

wings. The eggs are laid by the female onion fly on the young leaves, necks of onion seedlings or in the soil close to the base of onion plants. The onion [...] even death of the onion plant. The roots and leaves are harmed when the onion fly larvae tunnel into the onion bulbs. This damage may decrease the quality [...] Success of onion fly control starts with the right approach. Growers must carefully monitor the development of the onion fly. This way he knows when the first

Tobacco whitefly

peppers, yellowing of the flower stalks in gerbera, and serious yellowing of the leaves of French beans. Other symptoms include the appearance of chlorotic patches [...] adult. The larvae are found on the underside of young leaves and have an oval shape. The first instar larvae (crawlers) are mobile, whereas the rest of the [...] distinctively, the wings of the tobacco whitefly ( Bemisia tabaci ) are held vertical and parallel along the body. Damage symptoms The larvae of whitefly need

Vine mealybug

an adequate intake of protein, mealybugs must therefore ingest large quantities of sap, getting rid of the excess sugars in the form of honeydew. Charac [...] growing on this honeydew. Additionally, the white, waxy secretion of the mealybugs, reduces the ornamental value of the affected plants. Fruit and flowers are [...] oval shape and has no wings. The body is covered with a fine waxy material and have 18 pairs of wax rods round the edge of the body, and two slightly longer

Greenhouse whitefly

found on the oldest leaves. The adult emerges from the pupa via a T-shaped fissure. The adult whiteflies can usually be found in the top of the plant and [...] adult. The larvae are found on the underside of young leaves and have an oval shape. The first instar larvae (crawlers) are mobile, whereas the rest of the [...] General The greenhouse whitefly ( Trialeurodes vaporariorum ) is one of the major pests of vegetable and ornamental crops in greenhouses throughout the world

Obscure mealybug

layer of wax, the filaments around the body are longer (20-50% of the body size) and the two tail filaments are always markedly longer than the others [...] name from the fact that the body of the females from the third nymphal instar onwards are covered with a white waxy material in the form of powder, threads [...] an adequate intake of protein, mealybugs must therefore ingest large quantities of sap, getting rid of the excess sugars in the form of honeydew. Charac