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Cola-nut galls (Andricus lignicola) on pedunculate oak, caused by a cynipid gall wasp. Galls (from the Latin galla, 'oak-apple') or cecidia (from the Greek kēkidion, anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths [1] of plant tissues, similar to benign tumors or warts in
Poor growth and a variety of disorders such as leaf discolouration can be caused by a shortage of one or more plant nutrients. Poor plant uptake of a nutrient from the soil (or other growing medium) may be due to an absolute shortage of that element in the growing medium, or because that element is present in a form that is not available to the ...
Virescence is the abnormal development of green pigmentation in plant parts that are not normally green, like shoots or flowers (in which case it is known as floral virescence). [1] Virescence is closely associated with phyllody (the abnormal development of flower parts into leaves ) and witch's broom (the abnormal growth of a dense mass of ...
Life cycle of the black rot pathogen, the gram negative bacterium Xanthomonas campestris pathovar campestris. Plant pathology or phytopathology is the scientific study of plant diseases caused by pathogens (infectious organisms) and environmental conditions (physiological factors). [1]
Most bacteria associated with plants are saprotrophic and do no harm to the plant itself. However, a small number, around 100 known species, cause disease, especially in subtropical and tropical regions of the world. [15] [page needed] Most plant pathogenic bacteria are bacilli. Erwinia uses cell wall–degrading enzymes to cause soft rot.
Leaf spots can vary in size, shape, and color depending on the age and type of the cause or pathogen. Plants, shrubs and trees are weakened by the spots on the leaves as they reduce available foliar space for photosynthesis. Other forms of leaf spot diseases include leaf rust, downy mildew and blights. [4]
Two of my favorite spring plants, almost entirely based upon their progression from bud to leaf, are beech trees and false hellebore. Why the unfolding leaves of beech trees and other plants ...
In severely affected plants the growths can also appear on the stems and cause leaves to turn yellow and drop off, [4] leaves can also become distorted. [5] If the conditions causing edema are prolonged then the plant can become spindly and have stunted growth. [4] Edema can often be confused with a variety of other plant conditions, such as ...