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Rhytisma acerinum is the teleomorph of tar spot. In the spring, needle-shaped ascospores are released from overwintering apothecia in fallen leaf debris. [2] [7] These spores are disseminated by the wind and have a sticky coat to attach to new healthy leaves. [4] Once on the leaves, the spores germinate and penetrate through the stoma. [2]
Douglas Fir are used as Christmas trees and the aesthetic value can be decreased from R. pseudotsugae. The symptoms first appear as small yellow spots on current season needles in the fall/winter. In the spring the discolored areas on the needle expand and can spread to the whole needle, however bands of discoloration are often formed.
Symptoms include needles developing yellow spots, horizontal brown bands around the needles, swelling of needles, and off-white fruiting bodies formed on infected needles. [ 2 ] [ 3 ] Because Cyclaneusma is an ascomycete it produces two spore types, an asexual ( conidiomata ) and sexual ( ascomycota ) spore.
Paresthesia, also known as pins and needles, is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. [1] Paresthesia may be transient or chronic, and may have many possible underlying causes. [ 1 ]
Formication is the sensation resembling that of small insects crawling on (or under) the skin, in the absence of actual insects. It is one specific form of a set of sensations known as paresthesias, which also include the more common prickling, tingling sensation known as pins and needles. Formication is a well-documented symptom which has ...
The symptoms give the disease its name. The first signs of infection that can be seen are yellow and brown spots that develop on the living needles, [7] [8] which soon turn red. This infection starts on the base of the crown on older needles, which then turn a brownish red at the tip, while the rest of the needle remains green. [9]
Bidens alba is a species of flowering plant in the family Asteraceae, commonly known as shepherd's needles, beggarticks, Spanish needles, or butterfly needles. [1] Bidens means two- toothed, describing the two projections found at the top of the seeds, and alba refers to the white ray florets. [ 2 ]
A raspberry leaf spot infection initially causes dark green circular spots on the upper side of young leaves, which will eventually turn tan or gray. [3] These spots are typically 1–2 millimetres (0.039–0.079 in) in diameter, but can get as big as 4–6 millimetres (0.16–0.24 in). [4] These spots can also fall out, causing a shot effect.