node is the term for the regions of the plant where leaves are attached to the stem.
what is the term for the regions of the plant where leaves are attached to the stem?
node
disease symptoms occur primarily on the stems, leaves and can lead to whole plant symptoms. reddish brown lesions on the lower stem of soybean plants progress into brown cankers. in some cases, the disease can spread to all parts of the stem. stem girdling can result in premature plant death. grey streaking along the lower stem and taproot has also been observed. studies suggest a toxin may influence the development and symptomology of stem canker. leaf symptoms include interveinal chlorosis and necrosis during early reproductive stages. leaves eventually dry and fall off the plant as the disease worsens. stem canker has similar symptomology as brown stem rot, fusarium wilt, phytopthora stem rot, sudden death syndrome, tobacco streak virus, and sclerotinia stem rot, which can make distinguishing this disease particularly difficult. stem canker can be differentiated primarily by its long dark red or brown canker that can extend over multiple nodes. inside the stem, discoloration is localized to areas near the canker or lesion.
diaporthe phaseolorum var. caulivora
initial symptoms of "p. helianthi" infection can be found at the attachment of petiole to the stem on the lower portion of the plant. initial infection will cause brown necrotic regions with a chlorotic border. eventually these regions will grow into larger, brown to tan lesions and eventually into large cankers. cankers are found on the stem and will have a sunken border. cankers can be long, up to 6 inches, but do not appear until flowering. other early symptoms can include necrosis and bronzing of intervenial areas of leaves at or above the stem lesion. wilting and death of leaves above the canker also occurs. leaves above the site of inoculation can also show symptoms of being water soaked. this is sometimes accompanied by leave distortion. "phomopsis" stem canker is also characterized by extensive pith degradation to the point where the stalk is easily crushed under moderate thumb pressure. wilting is also a typical symptom, and extensive wilting can eventually lead to lodging later in the season. "phomopsis" also produces mycotoxins, which can cause additional symptoms such as premature ripening or early plant death.
diaporthe helianthi