Powdery mildew

epidemics in cereals, the ears may also be infected. In pepper, the fluffy colonies occur mostly on the underside of the leaf, because the fungus infects [...] to water and ‘hides’ on the underside of the leaves. Therefore, this is where the colonies mostly occur in these crops. In covered roses, the colonies [...] grow and branch out on the leaf surface. Small structures are produced, the haustoria, from which the fungus penetrates the plant cell and takes up nutrients

Oleander aphid

found in tropical to warm temperate regions throughout the world. It probably originated in the Mediterranean region, the origin of its principal host plant [...] oleander. Damage symptoms The colonies of bright yellow aphids can easily be seen on the shoots of the host plants. The damage caused by the aphid colonies is [...] is mainly aesthetic due to the large amounts of sticky honeydew produced and the resulting black sooty mould that grows on the honeydew. Growing tips can

Leaf miners

indirectly. The most direct damage is caused by the larvae mining the leaf tissue which can lead to desiccation, premature leaf-fall and cosmetic damage. In (s [...] lost before the harvest is affected. The size of a leaf tunnel depends on the stage of development of the leaf, the species of host plant and the species of [...] various crops in temperate parts of the world. Under natural conditions, the larvae of these species are parasitized by parasitic wasps and so cause few

Bugs

five nymphal instars and the adult insect. Several species of especially the families Miridae and Pentatomidae are found as pests in agricultural crops. [...] leaves and growing points with their piercing-sucking mouthparts and extracting nutrients from them, resulting in deformations and puncture holes. The most [...] harmful and beneficial species. Heteropteran bugs are insects which have flattened bodies and fold their wings flat over their body when at rest. The wings

Apple scab

between the cuticula and the epidermis of the plant cells. This causes lesions, on which conidiophores, structures which carry conidia, are formed which extend [...] through the cuticula. The asexual conidia are released and repeat the cycle of infection of new plant parts and spore production. In autumn, the fungus [...] fungus produces new pseudothecia in leaves that have already fallen off the trees. In response to the infection, the plants produce cork as a defence against

Aphidius colemani

typical 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 [...] Aphidius colemani The parasitic wasp is available in a bottle ( Aphipar ). Spread the material on rock wool slabs or in Diboxes Make sure the material remains [...] searching behaviour, which enables the wasps to track down and parasitize aphids , even when they are at low density. The behaviour of the female during egg-laying

Grapevine powdery mildew

according to the phenological growth stage and the severity of the infection. Early signs manifest as chlorotic (pale green to yellow) spots, which rapidly [...] while shoots and flowers exhibit stunted growth and poor fruit set. During berry development, the pathogen colonizes the epidermis, causing the skin to lose [...] bodies) attached in the bark crevices and plant debris. In spring, chasmothecia release ascospores during periods of favorable temperature and moisture, initiating

Mushroom

effects on humans and desirable taste and aroma. Most mushrooms sold in supermarkets have been commercially grown on mushroom farms. The most popular of these [...] crimini, and portobello. Many other mushroom varieties are also commercially available as growers and breeders search for new and unique tastes for the market [...] toadstool, is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. Edible mushrooms are the fleshy

Asian citrus psyllid

through most of the southern states and Mexico however the state of Florida is the most affected area by the vectored disease. Damage symptoms The psyllid [...] widely distributed in southern Asia and the disease is responsible for the destruction of several citrus industries in Asia and Africa. In North America, it [...] huanglongbing (HLB). Nymphs and adults of the psyllid take the bacteria into their bodies by feeding on bacteria-infected plants and then disease is spread

Pierce's disease of grapevine

vessels in roots, stems and leaves and multiply. The plant may react by producing gum and tylose, a glue-like substance, in the vessels. The bacteria, gum [...] (peaches and plums): In peach, the canopy of infected plants is compact and umbrella-like due to the shorter internodes. The foliage is denser and the leaves [...] along the margin or the tip from early to midsummer. The necrotic area spreads over the leaf from the margin and is marked by a chlorotic band. In the beginning