• Citrus mealybug

  male nymph forms a dark brown ‘prepupa’ from which a pupa rapidly develops, inside a white cottony cocoon. Females undergo little changes in form, passing [...] therefore ingest large quantities of sap, getting rid of the excess sugars in the form of honeydew. Characteristically, dark sooty moulds ( Cladosporium spp .) [...] 2.5 - 4 mm long and 2 - 3 mm in breadth. Seen dorsally, they have an oval form; they are soft and covered with a fine waxy material. They move very little

• Glume blotch

  similar brown lesions with pycnidia and perithecia occur. Perithecia are also formed on dead glumes and stems. In case of severe infection , the heads of wheat [...] become visible after five to seven days. On the lesions, new pycnidia are formed. The conidia that are produced in these pycnidia emerge in a pink slimy

• Oleander scale

  3 mm long. They quickly attach themselves to the plant and form a scale. Colonies mainly form on the underside of leaves. After 1 to 2 months, the female

• Angular leaf spot

  are translucent. When conditions are humid, a viscous bacterial exudate forms on the underside of the leaf. This exudate changes to a white film when it [...] Under humid conditions, bacteria ooze from the lesions on the leaves and form a secondary source of infection. They are dispersed by rain, irrigation water

• Shallot aphid

  shallot 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 [...] even in winter and early spring when temperatures are still low. Winged forms are produced and migrate to other crops until June.

• Buckthorn-potato aphid

  o 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 [...] hosts and start to reproduce parthenogenetically. Both wingless and winged forms are produced parthenogenetically. They are usually found in the lower parts

• Verticillium wilt

  brown stripes occur on the stem. In tomato, sometimes V-shaped lesions are formed on the leaf, between the veins. 'Early dying' disease of potato only occurs [...] In the senescent tissue, the resting mycelium or the microsclerotia are formed. The spread of the fungus by mycelium growth is limited. Dispersal from

• Black root rot of cucurbits

  line on cucumber roots. The lesions are slightly sunken and are mostly formed around the point of attachment of lateral roots and root hairs. The lesions [...] disinfection needs to be applied thoroughly and evenly. Phomopsis sclerotioides forms sclerotia which can survive adverse conditions for years in the soil, but

• Cactus mealybug

  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 [...] sedentary and only move occasionally. After the second instar, the males form a pupa. After a complete metamorphosis, a winged male emerges from this pupa

• Black bean 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 moulds grow on this [...] bean 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