• Verticillium wilt

  produces gum in the vessels. The presence of both the fungus and the gum causes the xylem vessels to get blocked, which in turn causes the plant to wilt [...] These leaves are pale-green, then orange-yellow. In the beginning the plant seems to recover at night. The symptoms may occur only in parts of the plant. Cutting [...] wind-dispersed to new hosts. In the senescent tissue, the resting mycelium or the microsclerotia are formed. The spread of the fungus by mycelium growth is

• Common asparagus beetle

  yellow spots. Eggs are oval and black to greenish brown and laid singly or in rows of 3 to 10 eggs, standing perpendicularly on the branches and leaves [...] which may contaminate the plant. Life cycle and appearance of Common asparagus beetle The life cycle of the asparagus beetle has the following stages: egg [...] instar and the adult beetle. Adult common asparagus beetles ( Crioceris asparagi ) have a shiny blue head, black antennae and a red thorax. The elytra

• Boisduval scale

  of tissue at the feeding site. In orchids, this scale tends to prefer the leaf midrib and the portion of the petiole that is covered by the sheath. Small [...] of Diaspi s are very similar in their appearance and damage symptoms. Here, the Boisduval scale is described in more detail, as it is the most important [...] of the scales on upper and lower leaf surfaces, fruits, and stems of plants. On palms, Boisduval scales are normally found on the leaves and stems. Toxic

• Cutworms

  Agrotis spp.) are occurring worldwide. Important species are for instance the black cutworm Agrotis ipsilon and the turnip moth Agrotis segetum . The larvae of [...] will occasionally tunnel into the growing stalk, disrupting the sap flow in the plant. Life cycle and appearance of Cutworms The adults of Agrotis spp. have [...] 40-55 mm and the dorsal thorax is covered with close-lying hairs. The eggs are white at first but rapidly turn darker. They are laid separately or in batches

• Onion thrips

  develops in six stages: egg, two larval instars, prepupa, pupa, and finally the adult insect. The eggs of the onion thrips (Thrips tabaci) are laid in leaves [...] petals and in the soft parts of stalks. They are inserted into the plant tissue with a saw-like ovipositor. Larvae are light to yellowish green in colour [...] a large head and bright red eyes. The colour of the adult depends on the food source. Onion thrips (Thrips tabaci) usually pupate in the ground, although

• Damping-off

  irreversibly. In potted plants the flower buds fall off. The side roots rot and very little of the root system survives. On the border between air and soil or [...] enable the spores to move through water. The zoospores are chemically drawn to the growing roots of young plants and move towards them through the soil water [...] lose their turgor or the leaf tips turn yellow, for example in flower bulbs. At first, the plants recover during the night, but later the plants wilt irreversibly

• Common cockchafer

  mandibles and long, hairy, well developed yellow legs. It takes three or four years for the larvae to fully develop. The grubs are 10 to 20 mm in the first [...] autumn, 30 to 35 mm by the following autumn, and 40 to 46 mm in the spring of their third year. The pupa is 25 to 35 mm long and whitish brown. [...] General The cockchafer ( Melolontha melolontha) , also known as the doodlebug or May bug is a European beetle of the genus Melolontha, in the family S

• Circular scale

  l parts of the world, mostly in association with the citrus industry. In more northern countries of its range, it occurs in greenhouses. In addition to [...] humid environments. In citrus, it tends to prefer the lower and central parts of mature trees. Circular scale prefers the leaves, but in high infestations [...] fruits, stems and trunks, and may cause yellowing of leaves, premature leaf and fruit drop, and stem dieback. First signs of an infestation are dark-purple

• Feltiella acarisuga

  acarisuga is available in plastic cups ( Spidend ). Make a hole in the lid and place the cup on the rock wool slab or directly on the soil Protect against [...] direct sunlight and water Leave the cup in place for at least two weeks The dosage of Spidend depends on climate, crop and spider mite density and should always [...] They are aggressive and adapt the amount of food they consume to the density of the spider mite population. Where there are large, localised concentrations

• Tomato leafminer

  ped mines in the leaves. Caterpillars prefer leaves and stems, but they may also occur underneath the crown of the fruit and even inside the fruit itself [...] behind the head. The prepupae of the tomato leaf miner ( Tuta absoluta ) are lighter than the feeding larvae and have a typical pink colouration on the dorsal [...] outside the leaf mines or fruit. Pupation takes place in the soil or on the surface of a leaf, in a curled leaf or in a mine. If they leave the mines they