Content
Treatment of bacterial burn of pear requires the gardener to have certain knowledge about the disease itself and its development. To cope with the problem, you have to use various methods. If you skip the initial stage of the disease or leave the trees without treatment, the result can be very disastrous. A bacterial burn will lead to the death of the garden in a short time.
What is bacterial blight of pear
This is the name of a dangerous disease of fruit trees caused by infection. The causative agent of pear fire blight is Erwinia Amilovora, a bacterium of the genus Erwinia. The disease spreads very quickly from diseased trees to healthy ones.
There are varieties of pears that are most susceptible to infection, and some are resistant to infection. The most vulnerable varieties are Bere Garli, Conference, Lukashovka, Favoritka. If measures are not taken in time to save the pear, the tree will die in 2-3 years.Fire blight affects all parts of the plant, from flowers and leaves to the root system. The degree of danger of damage depends on the age, type of pear, climatic conditions in the spring, and the richness of the tree tissue. Trees of any age are susceptible to damage. Photo of a bacterial burn of a pear:
Causes of infection and provoking factors
The causes of bacterial blight of pears in the garden are being studied quite actively. Scientists are trying to find a complete list of factors that lead to the onset of the disease. Today the main ones are:
- the presence of fire blight carriers – insects or birds;
- minor injuries or damage to pear trunks;
- excess nitrogen in the soil.
Also, bacteria are easily transferred from one tree to another in windy weather. Most often, the disease becomes active between the end of May and June. Favorable conditions for the emergence and spread of infection are an increase in air temperature above normal, humidity and rain.
The activity of the pathogen decreases as the temperature drops; in winter, the spread of bacterial blight among pear varieties is not observed. The question of how a pathogen gets from a diseased tree to a healthy one is still relevant.
Scientists studying methods of treating the disease have noted the following processes of bacterial burn spread in the garden. At a certain stage of development of the disease, amber drops form on the pear.
They can be located on fruits, bark or leaves. This is a released exudate containing entire colonies of bacteria. Any insect or bird that touches an infected drop becomes a carrier of the disease.
The development cycle of an infectious disease
The most susceptible part of the pear to the effects of pathogenic bacteria are the flower buds and inflorescences. The infection process begins with them and then spreads to the rest of the tree. The speed and course of the disease is directly dependent on the growth phase of the pear in which the initial infection occurred. For example:
- Budding period. The affected buds turn black and dry out, but remain on the branches.
- Pear blossom period. The flowers darken and fade, then the blackening spreads to the leaves and branches.
The last stage of a bacterial burn is characterized by softening of the bark and the release of white exudate. Then, when exposed to air, it acquires a brown tint. The tissues affected by the bacterial burn begin to peel off and become covered with blisters, and the bark acquires a “marble” hue.
The death of a pear occurs very quickly if pathogenic bacteria penetrate the roots. The root system turns black, which causes the tree to dry out.
Features of parts of a pear affected by bacterial burn:
- The set fruits darken after infection, dry out, and remain on the tree until autumn.
- The bark on the branches and trunk of the pear becomes covered with drops of white exudate, similar to mold, and becomes soft. Then it cracks and takes on the appearance of marble.
- The branches are covered with ulcers that move onto the trunk.
If you don’t start fighting fire blight in time, you can lose your entire pear orchard in a couple of seasons.
Signs of a bactericidal burn of a pear
The spread of bacterial burn occurs on the tree from top to bottom. In order not to miss the onset of the disease, the gardener needs to know the signs of the disease:
- The first one appears in the spring on the buds, then on the flowers.It does not matter how many parts are affected. First, wilting is observed, then drying out, the flowers turn black. Then the bactericidal burn moves to the rosettes of leaves and young twigs.
- Leaves. They turn black and curl, often looking burnt.
- Branches. Their tips turn black as if from fire and bend, the bark becomes covered with dark watery spots.
The difficulty in defining the disease lies in the similarity of symptoms with other processes. For example, moisture deficiency. Gardeners believe that the pear tree is drying out from lack of water and begin to flood the tree. Also, the condition of the cortex resembles necrosis, which occurs with bacterial cancer.
How to treat bacterial burn of pear
There is a conditional division of treatment methods into chemical and mechanical. In any case, success will depend on the degree of damage to the pear by bacterial burn.
The first option involves the use of special means for treating the tree. In the second, a radical method is used - removal of the affected specimens as a whole or parts thereof. Gardeners are getting rid of the pear tree, which is more affected by the burn than other trees.
If the disease has affected less than 30% of the pear area, then partial removal is recommended. Only diseased areas are cut out, capturing some of the healthy tissue. At the same time, instruments must be disinfected.
If the damage is not extensive, gardeners use treatments with copper-containing preparations. However, most often it is necessary to use antibiotics.
Treatment of bacterial blight of pear with antibiotics
This method is considered the most effective. Various antibiotics are recommended for treating pears from fire blight. The preparation of the solution depends on the concentration in which the drug contains the active substance. Among the popular ones:
- Streptomycin. The choice of drug is determined by its availability and low cost. Disadvantage: it quickly breaks down and stops working. Dosage – 1 ampoule per 5 liters of water.
- Gentamicin. 1 ampoule of the drug per 1 liter of water is enough. This is a strong antibiotic.
- Ofloxacin. The drug has a more severe effect on the source of infection. Used for medicinal dressings (1 tablet per 1 liter of water) and spraying (2 tablets per 10 liters of water). The dosage must not be violated.
- Tetracycline. In terms of cost and availability, it is on par with Streptomycin. Often used in duets. Tetracycline prevents the emergence of Erwinia resistance to streptomycin. To treat a pear for bacterial burn, dissolve 2 Tetracycline tablets in 3 liters of water.
Bacterial blight on pear seedlings can be treated fairly quickly with antibiotics. During the season, it is necessary to spray the trees, alternating a solution of streptomycin and the drug Skor. The procedure is carried out once every 2 weeks.
Antibiotic treatments are carried out 2-3 times per season. It is strictly not recommended to spray pears during periods of extreme heat, so that the microorganisms in the solution do not die under the influence of sunlight.
Treatment of bacteriological burns of pears with copper-containing preparations
Among copper-containing preparations in the treatment of “Antonov’s fire”, copper sulfate, copper oxychloride, and other copper preparations are used. A mixture of copper sulfate and lime mortar is popular, but it is important to maintain the proportions.If you add more vitriol than normal, it will scorch the leaves. If not enough, the composition will lose its healing properties. Therefore, it is best to take ready-made Bordeaux mixture.
Copper oxychloride works most effectively, and it is also less toxic to pears than vitriol. Deep penetration into the wood tissue will not occur, but insects will not carry bacteria on their limbs.
The main effect that copper preparations produce is to stop the development of bacteria. However, the infection is not destroyed. Therefore, gardeners more often use antibiotics or other means.
Other drugs for the treatment of bacterial blight of pear
This category includes biological products or some fungicides. The most famous:
- Gamair. Low toxicity for humans, but effective in the fight against pathogenic bacteria. When treating a bactericidal burn, use a solution of 2 Gamaira tablets per 1 liter of water. Spraying is carried out at weekly intervals from the moment the buds open 2-3 times. If signs of the disease are noticed, spraying is continued many times. Does not work in cool weather.
- Phytoflavin. Can also be used during cold weather. Dilute 20 ml in 10 liters of water, treat the pear several times. The consumption of the working solution is 3 liters per tree.
- Fitosporin. A drug that significantly reduces the occurrence of putrefactive processes. Used for severe lesions of the pear.
According to reviews from gardeners, the best effect is obtained by combining bactericidal agents with fungicides Skor, Energy or Previkur. Some remain supporters of radical methods - uprooting the tree. It is important not to move the tree around the garden and to thoroughly disinfect all tools.
Preventive measures
Measures to prevent bacterial burns:
- Mandatory inspection of the garden, starting from the very first days of spring.
- Treating the garden with insecticides to destroy pests that are carriers of infection.
- Weeding the garden area from weed.
- Selection of pear varieties resistant to the disease.
- Carrying out winter sanitary pruning with mandatory disinfection of tools. Burning cut branches.
- Pre-winter treatment with copper-containing preparations.
There is no point in treating bacterial burns in the fall - Erwinia does not reproduce during this period, but goes into the encapsulation stage. Antibiotics are powerless, and treatments will remove other pathogenic bacteria that weaken the tree’s immunity.
Conclusion
Treating a bacterial burn of a pear can take a lot of effort and time. However, this does not mean that saving the garden is impossible. The sooner the symptoms are noticed and measures taken, the greater the chances of complete victory and saving your favorite pear varieties.
