Bacterial canker in tomatoes
The bacteria that cause this disease are widespread in most parts of the world, especially Europe, and are found from time to time in the United Kingdom and cause many problems in the Channel Islands.
Bacterial diseases of tomatoes
This bacteria affects a small number of the Solanaceae family, the most important of which is tomatoes, and no infection has occurred in peppers and eggplants under natural infection conditions. Solanum nigrum, a member of the weed family, is infected with this bacteria
Only salvation.
The causal organism Al-Musayyab patients
Clavibacter michiganensis subsp. michiganensis (Smith, Davis et al) This disease is caused by beverage bacteria. It is a non-spore-forming, non-motile, irregular-shaped bacillus. Gram-positive. This microbe is a seed microbe. It can remain in the soil on the remains of the previous infected crop during the winter period. Optimal conditions for its growth are relative humidity.
Benefits and warm temperatures ranging between 27°C - 32°C (79°F - 90°F).
Classification of causal organism. Classification of the pathogen
Kingdom: Bacteria or Monera
Division: Actinobacteria
Class: Actinobacteridae
Order: Actinomycetales
Family Microbacteriaceae
Genus Clavibacter
Species C michiganensis
Symptoms of bacterial canker in tomatoes
There are usually no symptoms of canker bacteria on seedlings. However, infection of young plants leads to weak growth, wilting of branches, and yellowing And the leaves curl Lower. There may be no visible symptoms until flowers form. When mature plants are infected, there are two types of symptoms depending on the method of infection. Systemic infection occurs when bacteria enter the vascular system of the plant and attack most parts of the plant, and this is done through the seeds. There is also a secondary pathogen, where bacteria cause local infections in the leaves, stems, and fruits.
Symptoms of systemic bacterial canker infection in tomatoes
Infected seeds are the primary source of systemic infection, whether carried on the surface of the seed or within it. Symptoms appear on older leaves first, as they curl, turn yellow, and wilt, and eventually turn brown and die. This is known as Firing. Sometimes these symptoms are found on one side of the leaf or one side of the plant. When the chorus is incised longitudinally, the vascular bundles are colored yellow, then they turn to a light reddish-brown color, especially at the Nok nodes in advanced infections. Lightly colored lines are noted on the outer surface of the leg. These lines can darken and crack, and finally the mycelium can become perforated or hollow. Branches can break easily. Severe infestation may lead to the death of the plant. It is easy to separate the epidermis and outer peel tissue from the inner part of the plant.
The leg when the leg is pressed between the fingers. The tissues of this part have a soapy texture due to the microbe's production of a dense, sticky, greasy substance. The bacteria move internally until they reach the fruits through the vascular bundles, especially the bark. The vascular bundles are colored dark and grow through the vascular bundles until they reach the seed. This results in the presence of a soft, yellow stripe or braid extending from the stem to the seed. If the seed is infected in the first stage of its formation It does not grow fully and disappears. If the infection was after the beginning of formation, it continues to grow and becomes an internal carrier of bacteria. If the bacteria infects the fruits when they are small, they become deformed and do not grow. However, if they are infected when they are large, no external molds appear on them.
Symptoms of secondary infection with bacterial canker in tomatoes:
This infection results from sprays of contaminated water, contaminated tools used in agricultural operations, workers in the farm or greenhouse, as well as the remains of infected plants and host weeds. This infection is localized on the stems, stems, and branches:
And the fruits. Symptoms on the leaves are characterized by the presence of a dark brown to black edge of the leaflet surrounded on the inside by a yellow area interspersed between the healthy green inner tissue of the leaflet, which is free of any dead tissue, and the brown edges of the leaflet.
These edges may curl upward (11) Fig) relatively small spots grow on the fruits, mm in diameter, usually slightly raised, fat, yellow to brown in color and surrounded by a permanent white halo, so they are called bird’s eye Fig (12) Birds eye. These spots can be found on the stems and petioles. also. Secondary infestations do not often affect the crop, especially when they start late in the season.
Control resistance against bacterial canker in tomatoes
The best way to resist bacterial diseases is to plant disease-resistant varieties. But the reasons Bacterial diseases They mutate quickly and form new strains that can attack resistant varieties, if they exist. Therefore, it is difficult to provide these varieties, but there are cvs of tomatoes that have some resistance or have the ability to tolerate canker bacteria, and they have not been produced at the commercial level. To date, it has been proven from ongoing research that there are 2 genes 2 in tomatoes. It can lead to resistance to canker sore bacteria. So
Good sanitary measures must be implemented, whether in the greenhouse or the field, to reduce the risk of bacterial canker in tomatoes.
First: Practical cultures
1 - Resistance to weeds around and inside the field or greenhouse, especially host weeds.
Get rid of the remains of infected plants at the end of the previous season.
- Conduct an agricultural rotation with another crop that is not host to the pathogen for at least one year.
- Seedlings must be healthy and free of disease. In the case of producing seedlings in the greenhouse, this must be taken into account
(a) Clearing the greenhouse of any plants and disinfecting the surfaces of benches, tools, and wooden supports by washing them with surface solutions such as Calcium hypochlorite solution at a concentration of 1/2 TP3T, Physan, or any of the disinfectants.
Regolith because bacterial canker in tomatoes can survive on supports and walls of the greenhouse for more than 10 months. (b) Planting seeds in new trays and pots is better, but they must also be sterilized. If it is used, it must
Evaluate it by washing in a disinfectant solution such as Calcium hypochlorite or by solarizing it. (c) Sterilize the cultivation mixture with steam
(d) Examine the seeds before planting them to produce seedlings and ensure that they are free of contamination. It is best to immerse the seeds before sowing them in a diluted solution of HCI acid with a concentration of , provided that the pH of the solution is... for 30 minutes or a lifetime in hot water at a temperature of 25 130 545 °C ( F) for a minute. Then perform a germination test. Germination.
(e) Controlling the relative humidity, temperature, and ventilation inside the greenhouse to prevent the leaves from getting wet. (f) When irrigation, use low pressure to reduce wounds in young plants. It also reduces the spread of water spray that may contain bacteria that may cause bacterial canker in tomatoes
(g) Do not handle seedlings while they are wet, and ensure that the shoots are dry when transporting seedlings. E - Before starting planting in the field, all agricultural tools are disinfected and agricultural materials free of pathogens are used. 6 - If the seedlings are not produced by the grower, these seedlings must be of known origin, documented, and sparingly free of disease.
- In the field, if the irrigation is vertical, the low-pressure system is followed so as not to injure the plants and to reduce the spread of water spray.
- If bacterial canker is observed in tomatoes in the field, it is prohibited to work with it while the plants are wet to prevent the rapid spread of the disease.
- Care must be taken with fertilization, good drainage, not excessive use of water, weed resistance, and disease resistance
Chemical resistance against bacterial canker in tomatoes
It is difficult to resist bacterial canker in tomatoes after they have infected the plant. Also, starting a resistance program after symptoms appear has a negative effect due to its delay. Therefore, an infection prevention program must be implemented early during the crop’s growth, depending on the surrounding conditions suitable for its spread
Land, whether in the nursery or in the field.
Bacterial pesticides based on stabilized copper are effective in resisting bacterial canker in tomatoes. These pesticides are used sprayed on the shoots, and the spraying is repeated every 7 days or less depending on the bacteria present and the size and extent of plant growth. Taking into account the
Apply the spray solution to all parts of the plant and use the recommended dose.
The stabilizing action of copper depends on the free copper ion in the spray solution. Its concentration varies depending on the pH of the solution. Therefore, pesticide production companies create regulators, diffusers, and also additives to increase the efficiency of pesticides
Under normal conditions of use, this includes the pH of the spray solution. Therefore, you must follow the manufacturer's recommendations for additives
Mixing and use because excess copper ion can harm plant tissue.
There is numerous research in the United States of America indicating that tank mixing pesticides rancozeb + copper
Accelerates resistance to bacterial canker in tomatoes.
References
- https://www.alfilaha.com/wpalfilaha/%d9%85%d8%b1%d8%b6-%d8%a7%d9%84%d8%aa%d9%82%d8%b1%d8%ad-%d8%a7%d9%84%d8%a8%d9%83%d8%aa%d9%8a%d8%b1%d9%8a-%d9%84%d9%84%d8%b7%d9%85%d8%a7%d8%b7%d9%85/
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