• Citrus mealybug

  so that the light yellow to pink body is visible through its waxy covering. There is often a darker longitudinal stripe running over the body. The adult [...] search for a new feeding place and are capable of moving a reasonable distance over the plant. The male nymph attaches itself to the plant, whereas the females [...] defoliation. The overall effect is a reduction of photosynthesis and therefore the yield. Flowers and fruit often drop off. Plant sap is rich in sugars

• 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 also infects seeds and tubers, thereby creating a source of infection for the next crop. The dispersal to neighbouring plants is by mycelial [...] 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 occur

• Verticillium wilt

  new hosts. In the senescent tissue, the resting mycelium or the microsclerotia are formed. The spread of the fungus by mycelium growth is limited. Dispersal [...] residues. The fungus infects the roots of plants, directly or through wounds caused by for example nematodes. The fungus then grows into the vessels of [...] 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. Spores may be wind-dispersed

• Aphidius colemani

  of the Aphidiidae. First the host is examined by drumming with the antennae. This gives the wasp the information about whether the aphid is the right species [...] Aphidius colemani is widely used in the biological control of aphids . Aphidius colemani is used for the control of the following pests: Cotton aphid ( Aphis [...] products for advice on the best strategy for your situation. Best conditions for use of Aphidius colemani The parasitic wasp Aphidius colemani is most effective

• Bacterial canker of tomato

  occurs in the second half of the season. The first symptoms are wilting of the lower leaves and subsequent expansion of the wilt upwards. Cutting the stem at [...] tools. The bacteria infect the new plants by entering through wounds and then growing into the vessels of the plant. Plant growth is inhibited and the plant [...] infection is found, strict measures are taken to eradicate the infection. In tomato, growers must either destroy the infected crop entirely or, if the crop

• Angular leaf spot

  underside of the leaf. They enlarge to angular spots, often limited by the small veins. The distinctive feature is the way the lesions look when using different [...] leaves or leaves in the soil, but not independantly in the soil. Under humid conditions, bacteria ooze from the lesions on the leaves and form a secondary source [...] visible on the upper side of the leaf as irregular spots which are first reddish brown and then become necrotic. The foliar symptoms are the most important

• Cotton aphid

  as chrysanthemum and kalanchoe. The cotton aphid ( Aphis gossypii ) is distributed throughout the world but prefers the warmer regions. It has been a pest [...] greenhouses since the late 1980’s, particularly affecting cucumber. Damage symptoms The cotton aphid ( Aphis gossypii ) is an important vector for viral diseases [...] including the cucumber mosaic virus. Nymphs and adults extract nutrients from the plant and disturb the balance of growth hormones. As a result, the plant’s

• Loose smut of wheat

  survives inside the seed and when the seed germinates, the mycelium of the fungus grows upwards inside the plant into the growing tip and the seed primordia. It [...] Loose smut of wheat The seeds are infected during flowering and the infected seeds are the primary source of inoculum in the next crop. The fungus survives [...] invisible until head emergence. The first sign of infection is the appearance of a smutted ear. Instead of normal tissue, the ear contains a mass of olive-brown

• Root and crown rot of strawberry

  rot reported mainly from Brazil. The genus is quite complex, so the taxonomy may change. Pestalotiopsis clavispora is also called Neopestalotiopsis clavispora [...] strawberry. Plant development is slow, growth is retarded and rooting is poor. Transplants look weak and may die. It is hard to visually distinguish between [...] rot of strawberry Not much is known about the life cycle. The fungus produces ascospores and conidia, but their role in the epidemic has not yet been

• Root rot of carrot

  develop on the surface. Initially, the disease forms circular to irregular spots on the leaves that vary in colour from grey to almost black. The spots appear [...] after which whole sections of the leaf will die off. The fungus appears to prefer older tissue. In the field, the disease is difficult to distinguish from [...] to black lesions of various shapes. The lesions can merge and eventually cover the entire surface of the carrot. The affected areas are firm, shallow, and