Canker

Erebs, m. cancer crayfish grain, hard particle (in clay, etc.) knot (in ore, etc.) wart canker crab crustacean. 

Carboxylic acids vary considerably in strength. Among the strongest is trichloroacetic acid (Ka = 0.20) a 0.10 M solution of C13C—COOH is about 73% ionized. Trichloroacetic acid is an ingredient of over-the-counter preparations used to treat canker sores and remove warts. 

It is far superior to any other known remedy for the cure of all diseases arising from impurities of the blood, such as Scrofula, Rheumatism, Cancerous Humors, Erysipelas, Canker, Salt Rheum and Skin Disease. ... 

It cannot be helped. I must have only men I may trust to make the jury understand how this canker has spread. It will appear no more than the usual matter of oyer et terminer, as the clerks write it. ... 

Apples Canker Nectria galligena Bordeaux mixture, copper oxychloride... 

Plums Bacterial canker Pseudomonas syringae Copper oxychloride... 

Signs Plants infected with citrus canker have characteristic lesions on leaves, stems, and fruit with raised, brown water-soaked margins usually with a yellow hallow effect around the lesion. Incubation is typically 14-60 days. Older lesions may fall out, creating a shot-hole effect. Fruit production declines and then stops. The disease ultimately kills the tree. 

Gottwald, Tim R., James H. Graham, and Tim S. Schubert. "Citrus Canker The pathogen and its Impact." Plant Health Progress Online. August/September 2002. http //www.apsnet.org/online/feature/citruscanker/. September, 2006. 

Citrus Canker Eradication Program Environmental Assessment, April 1999. United States... 

Antoniou PP, Tjamos EC, Panagopoulos CG (1995) Use of soil solarization for controlling bacterial canker of tomato in plastic houses in Greece. Plant Pathol 44 438-447. doi 10.1111/j. 1365-3059.1995.tb01666.x... 

Besri M (1982) Solar heating (solarization) of tomato supports for control of Didymella lycoper-sici Kleb. stem canker. Phytopathology 7 939... 

Thomson SV (1996) Solarization of pear and apple trees to eradicate bacteria in fire blight cankers. Acta Hort (ISHS) 411 337-340... 

Sphaeronema. This disease, mainly a trunk canker, was first described in Ecuador in 1918 by Rorer and was attributed by him to Sphaeronema fimbriatum, better known currently as Ceratostomella fimbriata. It has also been reported to cause a pod rot. 

It is reported that in Venezuela (26, 36) this disease occurs in epidemic proportions in certain areas and causes serious trunk injury to 3 to 5% of the trees. It also occurs probably in other areas of tropical America. In Ecuador this disease is called machete disease, because the fungus, a wound parasite, infects through cuts and produces severe cankering in the trunk. No chemical control has been attempted, and burning the infected trees is the only control used at present in Venezuela. 

Disease and/or pest resistance If you have a particular local problem, such as nectria canker, seek suggestions and advice on resistant or less susceptible varieties. 

In fall and winter, canker bacteria, spread by rain-splash from the leaves, enter twigs through leaf scars to cause canker lesions. In spring and summer the foliage is attacked, but no new cankers are formed. 

Symptoms Dark brown spots on leaves in the late spring. These drop out leaving a "shot hole" appearance. Cankers usually occur on plum tree trunks and cherry branches. Initially, amber-colored gum exudes from a slight depression. Leaves become yellow and stems die back. 

It spreads quickly throughout the plant and cankers may develop. The fungus overwinters on infected fruit and cankers... 

What to do Prune out affected branches and remove fruit from the tree. Pick up windfalls. Do not compost any of this material. Take care not to damage fruit that is to be stored. Do not store any diseased fruit. Prune out cankers and diseased spurs. 

Also known as valsa or leucostoma canker, this fungal disease can be a serious problem on trees. 

Symptoms New shoots turn yellow, wilt and die back. The inner bark on infected twigs may show black or reddish brown discoloration. Gummy cankers form on trunks and branches and increase in size until they girdle and kill the affected part... 

Susceptible plants Apple, pear, hawthorn, and poplar. Some apples, such as Cox s Orange Pippin, Elstar and Gala, are particularly susceptible. More resistant apples include Bramley s Seedling, Lane s Prince Albert and Newton Wonder. Canker is a particular problem on wet, poorly drained soil. 

Symptoms Tree bark shrinks and cracks, often in concentric rings with the central piece of bark falling away. Deep lesions develop on the branches. Swelling can occur around the canker, and young twigs may die back. Cream-colored pustules may be seen in summer red spots are more common in fall. Papery bark can result Canker can ring an entire stem. Fruit skins crack fruits dry and can remain, mummified, on the tree. 

Symptoms Black canker produces dark lesions. Orange-brown canker produces a brown coloration on the skin, initially on the shoulder of the root. Purple canker produces a purple lesion with brown water-soaked margins. 

What to do Grow in a well-drained site. Grow a resistant variety such as Avonresister. Earth up in summer to stop the spores of black canker from reaching the roots. Use close spacing to produce smaller roots that may be less susceptible to some cankers. Control carrot fly (q.v.). Use a crop rotation. 

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