Search results
Results from the WOW.Com Content Network
Stroma is located in the black lesions of the infected leaves. [2] Conidiophores form non-infectious conidia that are released both in conditions of wetness and drought. [ 2 ] [ 7 ] The most favorable environment for the pathogen is when there is an extended period of moisture such as fog or rain, which prevents the leaves from drying out. [ 8 ]
This mycelial layer may quickly spread to cover all of the leaves. The lower leaves are the most affected, but the mildew can appear on any above-ground part of the plant. As the disease progresses, the spots get larger and denser as large numbers of asexual spores are formed, and the mildew may spread up and down the length of the plant.
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]
Pittosporum tenuifolium is a small evergreen tree endemic to New Zealand – growing up to 10 m (33 ft) – commonly known as kōhūhū and black matipo, and by other Māori names kohukohu and tawhiwhi. Its small, very dark, reddish-purple flowers generally go unnoticed, and are scented only at night.
Black sigatoka is a leaf-spot disease of banana plants caused by the ascomycete fungus Mycosphaerella fijiensis (Morelet), also known as black leaf streak. It was discovered in 1963 and named for its similarities with yellow Sigatoka, which is caused by Mycosphaerella musicola (Mulder), which was itself named after the Sigatoka Valley in Fiji .
Phyllosticta citricarpa is a plant pathogen, some strains of which cause a leaf condition called black spot on citrus plants. [2] As a result, such strains are subject to phytosanitary legislation in the European Union and the United States.
Honeydew drops on leaves Bald-faced hornet sips honeydew from a Disholcaspis quercusmamma gall covered by sooty mold Magicicada cassini "cicada rain" slow motion. Honeydew is a sugar-rich sticky liquid, secreted by aphids, some scale insects, and many other true bugs and some other insects as they feed on plant sap.
Black spot leaf disease is a physiological plant disorder that affects some grape varieties such as Concord.It is essentially a potassium deficiency that causes the leaves on a vine to turn purple and eventually black as chlorophyll is lost.