Obscure mealybug

therefore ingest large quantities of sap, getting rid of the excess sugars in the form of honeydew. Characteristically, dark sooty moulds ( Cladosporium spp .) [...] third nymphal instar onwards are covered with a white waxy material in the form of powder, threads, spiky projections or platelets. Eggs are laid in a sticky [...] males anf females is completely different. After the second instar, the males form a dark false pupa followed by a pupa in rapid succession. The actual pupa

Phytophthora blight

mycelium cells which are resistant to desiccation) or mycelium. Zoospores are formed from the overwintering structures which infect the host. Zoospores are spores [...] (structures containing sporangia, a type of spores) with sporangia are formed that protrude through the stomata. Secondary infection is either by germinating

Yellow rose aphid

quantities of sap to get sufficient protein. The excess sugar is secreted in the form of honeydew, making the crop and its fruit sticky. Black sooty moulds grow [...] rose aphid Aphids have a complex life cycle, with both winged and wingless forms of adults and a great variety in colour. In greenhouses, reproduction takes

Bacterial canker of tomato

but don’t fall off. On stems and shoots light stripes form, which then tear, allowing cankers to form. On tomato leaves, water-soaked lesions occur, usually

Glasshouse potato aphid

immediate effects of piercing by the aphids are visible in lower leaves in the form of yellow patches. Heavy yellowing may even be followed by defoliation. Life [...] potato 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

Cotton aphid

quantities of sap to get sufficient protein. The excess sugar is secreted in the form of honeydew, making the crop and its fruit sticky. Black fungal moulds ( [...] Cotton aphid Aphids have a complex life cycle, with both winged and wingless forms of adults and a great variety in colour. In greenhouses reproduction takes

Green peach aphid

quantities of sap to get sufficient protein. The excess sugar is secreted in the form of honeydew, making the crop and its fruit sticky. Black fungal moulds ( [...] peach 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

American serpentine leaf miner

from its egg, so that its mines join to form small plates. In various other crops one finds intermediate forms of tunnelling between these ‘plate mines’

Tomato moth

can reduce their marketability. In fruiting vegetables, large holes can be formed in both green and ripening fruit. The second generation of larvae often [...] loose silk cocoon is spun and two or three days later a red-brown pupa is formed, which gradually turns a glossy black. The moths are nocturnal, hiding during

Loose smut of wheat

It only becomes visible after head emergence. The teliospores that are formed on systemically infected seeds then infect neighbouring new seeds. They