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Septoria lycopersici infects the tomato leaves via the stomata and also by direct penetration of epidermal cells. [3] Symptoms generally include circular or angular lesions most commonly found on the older, lower leaves of the plant. [1] The lesions are generally 2–5 mm in diameter and have a greyish center with brown margins.
An aphid infestation can ruin a garden. Learn what causes aphids and how to identify, kill, and control them naturally for healthy plants with no aphid holes.
In a study on tomatoes, it was shown that the aphids preferred smooth to hairy leaves and that susceptible tomato plants had higher sucrose, lower quinic acid and higher alanine and tyrosine levels. [10] In lettuce, butterhead varieties are mostly moderately to highly resistant to the aphid whereas crisphead varieties are susceptible. [11]
[1] [2] Wilt, stunting and lack of vigor can be observed as the primary symptoms, and infected leaves can possibly show interveinal chlorosis that leads to premature defoliation. [ 3 ] [ 4 ] The distinctive characteristic of P. lycopersici is that it causes brown lesions on the surface of medium roots which are known as a brown root rot. [ 4 ]
Pests, herbicides, or environmental factors can all cause tomato leaves to curl. Learning to recognize the cause is the first step toward solving this common problem.
S. berthaultii and other wild potato species have a further anti-aphid defence in the form of glandular hairs which, when broken by aphids, discharge a sticky liquid that can immobilise some 30% of the aphids infesting a plant. [115] Plants exhibiting aphid damage can have a variety of symptoms, such as decreased growth rates, mottled leaves ...
Tomato plants are usually stunted and have poorly shaped leaves, or "fernleaf", when infected by CMV. Also certain strains of CMV can cause partial or total crop loss. CMV in peppers causes slightly different symptoms than the previously mentioned. Pepper plants often have severe foliar damage, shown as mosaic and necrotic rings.
Some groups of aphids feed predominantly in the parenchymal tissue of plants while most aphid species feed on the phloem sap. [6] The green peach aphid ingests sugary fluids via a membrane. [ 12 ] While feeding on a plant long term, Myzus persicae can uptake chloroplast DNA , even though the chloroplasts themselves are uninjured.