Gum disease, or hommosis , is a painful phenomenon that occurs in various plants, most often in woody plants, characterized by the release of amber or brown, thick and sticky fluids on the aerial parts: mainly on the trunk, branches, fruits, less often - on the leaves.
The causes of the phenomenon are diverse - injuries, frost-holes, unfavorable growing conditions, damage by insects, and damage by microorganisms.
Content
Gumming of woody plants
Most often found in cherries , also in plums , peaches and other representatives of plum ( Amygdalaceae ); in warmer countries - in real acacias , in different species of astragalus ( Astragalus ), in oranges ( Citrus ), mulberry and other trees.
In cherries, gum flows from cracks in the bark of the trunk and branches, often in very significant numbers. This is a solid, light yellow and transparent, but sometimes cloudy and brown mass, known by the name of cherry glue ; is a mixture of arabin and cerazine . According to Wiegandt and Frank, its formation takes place as follows: first, separate vessels completely filled with gum begin to come across the wood, then small specks appear in the wood and in the bark in different places - emerging foci of gum formation. Here, a special abnormal parenchyma forms in the wood, which gradually dies, turning into gum. Then the surrounding normal wood begins to gradually decay, increasing the amount of gum. At the same time, destruction is also taking place in the crust. The disease can begin with the bark. Part of the cambium may also collapse - in such a place, of course, further growth of the tree becomes impossible, the disease corrodes the tree. The accumulated gum spills out, revealing wounds, often very deep. Nevertheless, gum therapy, which is believed to be only a symptom of the disease, is due to local accumulation of spare plastic substances and water in the absence of normal plant requirements. So, the loss of kidneys, especially in the spring, and consequently, the loss of the ability to properly process spare substances entails gamma-detection. The tree also suffers from serious injuries, excessive fertilizer and cold, heavy soil that retains water for a long time. In the latter case, the plant perceives too much water, dissolves a lot of reserve substances, not being able to use them normally. There is also an indication that the disease causes a special fungus Coryneum beyerinckii Oud. Self-healing in nature was almost not observed.
Just as cherries give cherry glue, real acacias ( Acacia senegal and others) give Arabian gum ( gum arabic ). Elements of the cortex turn into gum in them. Gum arabic proper comes from the inner bark, while its middle part gives gum, similar to cherry. The cause of cameo detection in Senegalese acacia is suggested by the effect of dry desert winds on the plant. There are also researchers who refuse to see a painful phenomenon in acacia gum.
Different types of astragalus give tragum gum , originating (according to Moth ) from the cells of the core and the core rays through their gradual disorganization. When wet weather is replaced by drought, the tragant formed inside the plant is squeezed out by surrounding tissues to the outside in the form of sheets and plates.
Cameodecision was also observed in oranges, lemon and orange trees ( Citrus species), in which it constitutes an undoubted and dangerous disease ( "mal della gomma" of Italians), as well as in one grape disease - "mal nero" , common in southern Europe.
Necessary preventive measures in the fight against gum trees: compliance with the rules of agricultural technology , good soil drainage , proper pruning and fertilizing, treatment of frost cracks and wounds, spraying with Bordeaux fluid . It is recommended to beware of serious injuries during the growing season and choose a looser soil. As a remedy, cutting wounds to healthy wood is advised.
Gumming of herbaceous plants
When cultivating tomatoes and Cayenne pepper ( Capsicum frutescens ) it sometimes happens (in Italy very often) that already in July many plants begin to lodge, their leaves first turn yellow, then become dirty brown and finally dry, and on the lower part of the main the stem and at the bases of large branches appear moist, as if wounded, places and gum forms on them. Bacteria are abundantly seen here, which is why the disease itself is sometimes called bacteriosis.
Of the cultivated industrial crops, the most harmful is cotton gum dropping caused by the bacterium Xanthomonas malvacearum , which is characterized by the appearance of oily gray spots covered with gum. Bolls rot, affected plants turn yellow, dry, break off and die. Necessary preventive measures: destruction of plant residues after harvesting cotton, autumn plowing, harvesting healthy seed material with subsequent dressing.
Literature
- Babayan A.A. , Cotton Gommosis, - Yerevan, 1963.
- Dictionary-reference phytopathologist // edited by P. N. Golovin , 2nd edition, - Leningrad, 1967.
Links
- Camedetection // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.
- Gumming // Great Soviet Encyclopedia : [in 30 vol.] / Ch. ed. A.M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978.
See also
- Sap