• 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

• Tobacco whitefly

  transmission of viruses, including TYLCV in tomato. The consumption of plant sap and secreting of honeydew by whiteflies reduce the aesthetic value of crops. [...] irregular ripening in tomatoes and sweet peppers, yellowing of the flower stalks in gerbera, and serious yellowing of the leaves of French beans. Other [...] identified on tobacco in Greece in 1889, hence the name tabaci . It has subsequently been found in most tropical and subtropical countries of the world. The original

• 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

• 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

• Persea mite

  mite ( Oligonychus perseae ) a key pest in avocado production worldwide. It lives and feeds on the undersides of avocado leaves, where it forms small webbed [...] the life cycle from egg to adult can be completed in as little as two to three weeks, resulting in multiple overlapping generations during the season [...] colonies along the main veins. Their feeding punctures the leaf tissue, resulting in small, round necrotic spots that can merge into larger brown or bronze patches

• 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

• 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

• Two-spotted spider mite

  such webs in which the mites live. The webbing and spotting on the leaves affects the appearance of the crop. This is of particular concern in ornamental [...] damage can also be seen on the upper surface of leaves as small yellow dots. The destruction of cells results in reduced photosynthesis, increased transpiration [...] eventually the whole plant, may die. In tomatoes and cucumbers, as little as 30% damage of the leaf surface can lead to loss of the crop. The nymphs and adults