• Woolly apple aphid

  seen, mainly on spurs and branches. Many generations occur during the summer months, also on new growth. Water shoots arising from the trunk or main branches [...] North American origin and has been distributed to other parts of the world mainly via infested apple rootstocks. It can occasionally also be found in pear [...] branches, are very frequently attacked. The aphids mainly spread through young, wingless nymphs which crawl or are blown by the wind from tree to tree. Sometimes

• Maize

  corn ( Zea mays subsp. mays ), is a large grain plant that divided in six main types: flint corn, dent corn, popcorn, pod corn, sweet corn and flour corn [...] domesticated by the indigenous communities in Mexico and it still plays a main role in the preparation of Mexican food dishes. The leafy stalk of the maize

• Lemon

  About Grown mainly for its juice, this well-known yellow citrus fruit is used widely for culinary and other domestic purposes throughout the world. Citrus

• Charcoal rot

  the roots may show the same discolouration of the internal tissues of the main roots. In most crops, necrotic lesions on the roots are the first symptoms [...] materials etc. The fungus may be transferred on seed but this is not considered a main source of infection. Optimum conditions for this fungus are temperatures

• Southern blight

  and rotting of the stem, resulting in the destruction of the cortex and the main root. As a consequence, leaves higher up in the plant start yellowing. Severely [...] and rotting of the stem, resulting in the destruction of the cortex and the main root. In highly humid conditions, white mycelium growth is observed on the [...] of the young tissues and softening of the stem, cotyledons, and roots. The main damage caused by damping-off is reduction of the stand, meaning it is very

• Black rot of carrots

  Alternaria radicina ) is a seed-transferred carrot disease. The seeds are the main source of primary infection and this may lead to death of seedlings. From [...] Practice crop rotation, in particular when spores surviving in the soil are the main source of infection. Especially wheat and barley reduce the number of surviving

• Aphids

  cotton aphid ), mainly on Cucurbitaceae, but also on chrysanthemums, and sweet pepper. Macrosiphum euphorbiae ( potato aphid ), mainly on Solanaceae and [...] various ornamental crops. Aulacorthum solani ( glasshouse potato aphid ), mainly on Solanaceae and various ornamental crops, e.g. begonia. Aphids life cycle [...] Aphids can transmit pathogenic organisms, particularly viruses. Viruses are mainly transmitted by the winged individuals. Potato virus Y (PVY) is transmitted

• Broad mite

  plant cells, secrete substances that disturb local growth. Leaf feeding is mainly concentrated on the underside near the leaf stalk, which tends to cause [...] becomes so dense that there is no more green tissue visible. In most cases, the main veins are untouched, causing them to stand out as a green pattern against [...] brown leaf tissue. Brown, corky patches can appear on the leaf stalks and main stems. The growing tips of affected plants acquire a misshapen appearance

• Pomegranate bacterial blight

  of fruits under severe infection. Disease cycle Infected cuttings are the main source of inoculum and wind splashed rains plays important role is spread

• Gerbera

  are now many cultivars that differ greatly in size, shape and colour. The main colours are white, yellow, orange, red and pink, but one flower can have