Search results
Results from the WOW.Com Content Network
Rhytisma acerinum is a plant pathogen that commonly affects sycamores and maples in late summer and autumn, causing tar spot. Tar spot does not usually have an adverse effect on the trees' long-term health. [1] R. acerinum is an Ascomycete fungus that locally infects the leaves of trees and is a biotrophic parasite. [2]
It is responsible for the black spot disease on papaya trees. It affects generally leaves and fruits at any time. It affects generally leaves and fruits at any time. Sporodochia of Asperisporium caricae was growing under side of leaf, dark blackish brown to black, stroma well-developed, erumpent .
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]
Citrus Black Spot has a large economic impact on many countries because the black blemishes make it undesirable for human consumption and therefore the infected fruit cannot be sold. This type of economic impact is felt most in Australia and South Africa where the disease has been present for a number of years. [ 37 ]
Citrus canker is a disease affecting Citrus species caused by the bacterium Xanthomonas (X.axonopodis; X. campestris).Infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit.
Stegophora ulmea is a foliar disease of elms commonly known as black spot of elm, twig blight, and elm leaf scab. [1] It is characterized by yellow spots that become black spots on the leaves. The pathogen is an ascomycete fungus native to North America. Stegophora ulmea is its teleomorph name. [2]
Circles, Xs, and dots in various colors identify which trees are to be cut, which ones are hazards, and which ones should be left alone. They also mark property boundaries and environmental concerns.
On the apple tree, the infections occur on leaves, fruit and young twigs. [4] The brightly colored spots produced on the leaves make it easy to identify. Small, yellow-orange spots appear on the upper surfaces of the leaves, anytime from April to June. [5] These spots gradually enlarge and turn orange or red and may show concentric rings of color.