Black sigatoka disease

turns brown and ultimately dies. In cases of severe infection leaves may die within a few weeks. Because of the lack of leaf tissues, fruit maturity is [...] leaf-spot of banana. Damage symptoms Black sigatoka (Mycosphaerella fijiensis ) first causes small, light yellow spots or streaks on leaves of about one [...] adjacent stomata. Both types of spores can germinate within two or three hours under humid conditions, but infection takes a minimum of two or three days under

Bacterial spot

volunteer plants and crop debris Avoid waste piles in the vicinity of the greenhouse or field Resistant cultivars of pepper are available and should be used Prevent [...] vesicatoria in tomato causes small, water-soaked spots on leaves which are first round and become more angular as they grow. The centre of the lesions [...] cracked scab. Life cycle and appearance of Bacterial spot Xanthomonas vesicatoria survives on volunteer tomato plants in the field and on diseased plant debris

Onion thrips

finally the adult insect. The eggs of the onion thrips (Thrips tabaci) are laid in leaves, flower petals and in the soft parts of stalks. They are inserted into [...] leaves and the black dots of their excreta indicate their presence in the crop. The vigour of the plant is reduced by loss of chlorophyll. When infestations [...] thrips (Thrips tabaci) usually pupate in the ground, although pupae can also be found on leaves, in flowers or in other sheltered places. The prepupal and

Tobacco aphid

) probably evolved from the peach potato aphid in the Far East and is a key pest of tobacco crops in both the United States and South America. The tobacco [...] tobacco aphid ( Myzus persicae subsp. nicotianae ) is also encountered in a range of crops in greenhouses, such as sweet pepper, aubergine, chrysanthemum, and [...] therefore need to extract large quantities of sap to get sufficient protein. The excess sugar is secreted in the form of honeydew, making the crop and its fruit

Apple collar rot

optimal for crop growth. Phytophthora overwinters in roots, infected tubers and bulbs or in the soil in different stages: as oospores (sexual overwintering [...] ion of the roots. On the foot, dark brown lesions with sharp borders occur. Above the graft and on leaves, dark brown, irregular lesions occur. In strawberry [...] Phytophthora cactorum is a plant pathogen that causes root rot, rhizome rot of strawberry, apple rot, apple collar rot and crown rot. It has an extremely

Cotton aphid

therefore need to extract large quantities of sap to get sufficient protein. The excess sugar is secreted in the form of honeydew, making the crop and its fruit [...] life cycle, with both winged and wingless forms of adults and a great variety in colour. In greenhouses reproduction takes place by parthenogenesis, with [...] balance of growth hormones. As a result, the plant’s growth is retarded giving rise to deformed leaves or, if the infestation occurs early enough in the season

Potato aphid

therefore need to extract large quantities of sap to get sufficient protein. The excess sugar is secreted in the form of honeydew, making the crop and its fruit [...] specifically characteristic of the potato aphid and is particularly visible in the nymphs. Immatures have a light dusting of whitish-grey wax. The aphids [...] balance of growth hormones. As a result, the plant’s growth is retarded giving rise to deformed leaves or, if the infestation occurs early enough in the season

Cottony soft rot

death of plants. Life cycle and appearance of Cottony soft rot Cottony soft root ( Sclerotinia sclerotiorum ) overwinters as sclerotia and mycelium in dead [...] plant pathogenic fungus. It has a very wide range of host plants. Damage symptoms The first symptoms of a cottony soft root ( Sclerotinia sclerotiorum ) [...] mycelium grows on the lesions, giving this disease its name cottony soft rot. In the mycelium, big, dark sclerotia are formed. They can easily be seen with

Pea blight, leaf and pod spot

) causes foot rot in peas, whereas Ascochyta pisi does occur sometimes at the stem base but is not part of the foot rot syndrome in peas. Infected seeds [...] Life cycle and appearance of Pea blight, leaf and pod spot Ascochyta pisi hardly survives in the soil or on crop residues because of its poor saprophytic [...] lesions of stems, leaves, and pods (pea leaf spot and pea pod spot). Damage symptoms Ascochyta pisi causes spots on leaves, stems and pods of peas. The

American serpentine leaf miner

cosmetic damage. In tropical and subtropical areas this can lead to burning in fruit such as tomato and melon. Loss of leaves also reduces yield. In full-grown [...] usually of less significance. Seedlings and young plants can be completely destroyed as a result of the direct damage caused by leaf miners. In gerbera [...] toothed 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