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Black knot occurs only on the woody parts of trees, primarily on twigs and branches, but can spread to larger limbs and even the trunk. Olive-green swellings from the disease are visible in the late spring; as it spreads and matures, typically by autumn, rough black knots circle and kill affected parts. The knots vary in diameter from one inch ...
Taphrina pruni is a fungal plant pathogen of blackthorn (Prunus spinosa) that causes the pocket or bladder plum gall, a chemically induced distortion of the fruit (sloes), producing swollen on one side, [1] otherwise deformed and flattened fruit gall without a stone. [2] The twigs on infected plants may also be deformed with small strap-shaped ...
Calico genus Ilarvirus, Prunus necrotic ringspot virus (PNRSV) : Enation genus Nepovirus, Tomato black ring virus (TBRV) : Infectious bud failure genus Ilarvirus, Prunus necrotic ringspot virus (PNRSV)
A fungus in the genus Taphrina often attacks the plums; the young ovaries swell, often much larger than full grown plums, become hollow and often persist on the tree in winter. Known as "plum pockets", they appear pale green, leathery to the touch, and hollow with the exception of a few fibrous bands. The disease reduces regeneration of the plums.
Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). [1] Organisms that cause infectious disease include fungi , oomycetes , bacteria , viruses , viroids , virus -like organisms, phytoplasmas , protozoa , nematodes and parasitic plants . [ 2 ]
Shot hole disease is a major concern of the stone fruit industry. It is estimated that 80% of the California almond crop may be infested with shot hole disease, resulting in a potential yield loss of 50-75%. [3] In the 1930s, it was found that applications of Bordeaux mixture reduces shot hole disease on peaches from 80% to 9%.
Brachycaudus helichrysi is a serious pest of stone fruits. It forms dense colonies on the underside of the leaves of the primary host causing curling, [4] twisting and distortion of the foliage, the shedding of flowers and the dropping of young fruit. [8] It is one of several species of aphid that can transmit the virus that causes plum pox. [8]
Branch knot Sphaeropsis tumefaciens: Brown rot (fruit) Phytophthora citricola Phytophthora citrophthora Phytophthora hibernalis Phytophthora nicotianae var. parasitica = Phytophthora parasitica Phytophthora palmivora Phytophthora syringae. Charcoal root rot Macrophomina phaseolina: Citrus black spot Guignardia citricarpa: Damping-off Pythium sp.