• Beet armyworm

  es for the growth of the crop. With a substantial population of caterpillars, the damage can spread to the stems, and in the worst cases to the fruit. [...] plants. In both the greenhouse and the field, it is a major pest of sweet pepper. Damage symptoms Older caterpillars migrate to the top of the plant where [...] Beet armyworm The beet armyworm (Spodoptera exigua) is a small, nondescript moth, that hides during the day and is active only at night. The forewings are

• Melon thrips

  to pale white in colour. The nymphs resemble the adults in general body form but it lacks wings and are smaller. Nymph development time is dependent on [...] flowers. In addition to direct damage, it also transmits virus from infected to healthy plants. Life cycle and appearance The reproduction in Thrips palmi [...] to 8 eggs per day, with 3 to 164 eggs lays during their lifespan. Mated female lays 3 to 204 eggs. Eggs are deposited in leaf tissue in a slit cut by female

• Cottony soft rot

  base and the roots, whereas the ascospores infect the above-ground plant parts. In greenhouses, usually only mycelium is produced by the germinating sclerotia [...] sclerotia. The fungus grows quite rapidly inside the plant and kills the host cells. On the infected plant tissue white, fluffy mycelium occurs with new dark [...] cottony soft rot. In the mycelium, big, dark sclerotia are formed. They can easily be seen with the naked eye and look like rat droppings. The symptoms may

• Early blight

  General The only known stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause [...] or when the leaves are wet. Small differences in optimum temperature occur between species, but in general the risk of Alternaria infection is larger under [...] crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and barley reduce the number of surviving

• Black rot of carrots

  General The only known stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause [...] or when the leaves are wet. Small differences in optimum temperatures occur between species, but in general, the risk of Alternaria infection is larger [...] crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and barley reduce the number of surviving

• Tea spider mite

  eggs in their life cycle. The blood red colour eggs are laid all along the veins and mid-rib on upper surface of the leaves. Freshly hatched larva is yellow [...] of months during winter. The life cycle is shorter (10-12 days) during summer period and it takes longer period of 28 days in colder weather. Tea spider [...] causes damage to the tea plant which sucks the sap of leaves and occasionally on petioles. Red spider mite attacks the upper surface of the mature leaves

• Woolly apple aphid

  trees sheltering in cracks and under loose bark. The nymphs become active in late March or April (in the northern hemisphere) and around the end of May, large [...] occur during the summer months, also on new growth. Water shoots arising from the trunk or main branches, are very frequently attacked. The aphids mainly [...] Contrary to the situation in America, South Africa, and Australia, woolly aphid does not infest roots in Europe (except rarely if they occur above the ground)

• Bacterial canker of tomato

  with a brown centre. In potato, the disease usually only occurs in the second half of the season. The first symptoms are wilting of the lower leaves and [...] expansion of the wilt upwards. Cutting the stem at the foot shows whitish ooze with bacteria in the case of C lavibacter infection, but other than that the disease [...] Both in greenhouses and in the field, spraying may also spread the bacteria. The bacteria can also be dispersed by machinery, crates and tools. The bacteria

• Black leg of seedlings

  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 [...] 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 [...] soil or substrate the plant turns brown. A typical symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger nail

• Phytophthora blight

  leaf wetness is required. Dispersal is by wind and rain causes the pathogen to be returned to the soil from infected plants. Dispersal in the soil happens [...] 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 [...] higher water content than is optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil in different stages: as oospores