Cercospora leaf spot

humidity favours the spread of the disease and severity. The fungus has the ability to overwinter in plant debris and remains in the field for long time [...] Veni GoKlean at the rate 1.25 to 1.5 ml per litre of water at 12-15 days intervals as preventative spray and or after recognition of the disease symptoms [...] many species of Cercospora species depending on the plant type infected. Infected seeds, infected plants and plant debris are primary source of infection

Phytophthora blight

from the root to the foot, but direct infection of the foot also occurs. Exudates leaking from growing root tips promote germination and attract the zoospores [...] 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 [...] through the skin. The Great Famine was a period of mass starvation caused by this disease which ravaged potato crops throughout Europe during the 1840s.

Cottony soft rot

infects the stem base and the roots, whereas the ascospores infect the above-ground plant parts. In greenhouses, usually only mycelium is produced by the germinating [...] range of host plants. Damage symptoms The first symptoms of a cottony soft root ( Sclerotinia sclerotiorum ) infection are water-soaked lesions at the stem [...] germinating sclerotia. The fungus grows quite rapidly inside the plant and kills the host cells. On the infected plant tissue white, fluffy mycelium occurs

Apple collar rot

from the root to the foot, but direct infection of the foot also occurs. Exudates leaking from growing root tips promote germination and attract the zoospores [...] root system and black discolouration of the roots. On the foot, dark brown lesions with sharp borders occur. Above the graft and on leaves, dark brown, irregular [...] zoospores. The pathogen grows into the stem and on the plant surface and new sporangiophores (structures containing sporangia, a type of spores) with sporangia

Red palm weevil

Due to the specific morphology of the palms, direct or indirect destruction of the apical bud will lead to the death of the plant, which makes the red palm [...] cycle and appearance of Red palm weevil The adults of the red palm weevil ( Rhynchophorus ferrugineus ) are typical weevils: the head extends with a long [...] and body comprised of 13 segments. Fully grown larvae migrate to the periphery of the palms to build a solid elongated cocoon made of rolled-up palm fibres

Two-spotted spider mite

to the host plant by feeding on plant sap. They mainly occur on the underside of leaves where they pierce the cells and suck out the contents. The empty [...] on the leaves affects the appearance of the crop. This is of particular concern in ornamental crops. Life cycle and appearance of Spider mite Two-spotted [...] yellow, and in many plants the damage can also be seen on the upper surface of leaves as small yellow dots. The destruction of cells results in reduced

American serpentine leaf miner

roughly one hour the larva crawls out of the leaf and falls to the ground. This occurs in the early morning. The larva crawls into the ground to pupate [...] enter the plant tissue via the feeding spots. Life cycle and appearance of American serpentine leaf miner The life cycle of a leaf miner has the following [...] ovipositor, usually in the upper side of the leaf. Egg spots are oval and hard to distinguish from feeding spots. The larvae of Liriomyza trifolii are

Oleander aphid

rather than eggs and that the progeny are clones of the adult female. The nymphs feed in colonies on the shoots at the top of the plant. Nymphs progress through [...] 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 [...] host plants. The damage caused by the aphid colonies is mainly aesthetic due to the large amounts of sticky honeydew produced and the resulting black sooty

Tomato leaf miner

roughly one hour the larva crawls out of the leaf and falls to the ground. This occurs in the early morning. The larva crawls into the ground to pupate [...] bacteria enter the plant tissue via the feeding spots. Life cycle and appearance of Tomato leaf miner The life cycle of a leaf miner has the following stages: [...] percentage of the larvae remain hanging on the leaf and pupate there, sometimes on the upper surface but more commonly on the underside. The late third

Caterpillars

to crops. The most harmful caterpillars that occur in greenhouses belong to the Noctuidae (the noctuid or owl moths), which is the largest of all lepidopteran [...] that damage greenhouse crops is the leafroller family, the Tortricidae. The name ‘leafroller’ refers to the fact that the caterpillars often live in rolled-up [...] not able to chew and therefore graze the underside of leaves. This causes a window effect where the epidermis of the upper leaf surface remains undamaged