Among the diseases of fruit trees there is one not quite clear origin, with which summer residents are struggling, but often unsuccessfully, and therefore anyone who encounters how black leaves on a pear should know what to do in such a situation.
If you notice that your pear has begun to twist and blacken the upper leaves, then most likely it is a disease called a bacterial burn, which should not be confused with sunlight. The reason for this is bacteria, which are carried with air currents, on the paws of birds for long distances. In a short time in the region where the disease is fixed, its outbreak occurs and it is considered quarantine.
What does a bacterial burn look like?
Most often the plant is affected at a time when sunny days are coming, it gets hot on the street and regular rains occur without a significant drop in temperature. In such a greenhouse climate, a harmful bacterium is activated and affects the most fragile - peduncles. They begin to fade, dry up, and then completely fall off.
The second stage of bacterial burn development, when the apical leaves turn and turn black on the pear. On each young branch the most extreme leaves suffer - at first on the periphery there are brown maculae. This process is not pronounced, and therefore it can simply not be noticed.
Very soon the spots turn black and cover the entire leaf plate, causing it to dry up and curl into the tube. And so it happens alternately with all the branches in a fairly short period.
Why do the young pear grow stained with leaves, but not on the old one?
It can be noted that when in the district the plantings of pears are massively infected with a bacterial burn, then young trees are affected first of all up to the age of ten, and old pears are practically unscathed.
It's all about the tenderness of young shoots of such trees and in active sap flow. In addition, the immunity of a small tree is much weaker than that of an old one. But there are some varieties that are very resistant to any disease of fruit trees, that even such an insidious disease as a bacterial burn does not bother them.
Methods of prevention and control of the disease
Now you have learned why the pear grows black and twists the leaves. But, unfortunately, it is not always possible to prevent a bacterial burn, but it is possible to increase the resistance of trees. Every year at the beginning of the vegetation period, spraying of pear plantings with a solution of copper sulfate or Bordeaux fluid is carried out - all that contains copper in its composition.
If nevertheless it is noticed that some branches have signs of defeat, then it is necessary to proceed immediately to sanitary pruning. This requires a sterile tool, a disinfectant and a metal bucket.
Cut each branch should be retreated no less than 20 centimeters from the point of destruction, because even healthy-looking fabrics located in the immediate vicinity are also affected from the inside, and therefore sparing trim will be a waste of time.
It should be remembered that after pruning each branch, the blade of the pruner must be treated with any disinfectant on an alcohol basis so as not to spread the bacteria to other branches or trees. Cut leaves infected by a bacterial burn and branches are not folded onto the ground or into a bag for disposal, but into a metal container for further combustion.
After trimming, the sections are also disinfected and start to be sprayed. This will require the drug Ofloxacin, which is available as a solution in a vial for injections or in tablets. The medicine is an antibiotic, because it is the bacterium that is to blame for the development of the disease.
The product is diluted with boiled cool water and with the help of a sprayer they process the branch behind the branch, not missing a single leaf. Such approaches can be up to three, at regular intervals. Unfortunately, the disease does not always manage to be defeated and the tree has to be destroyed, and therefore the sooner the treatment begins, the more chances for the pear to survive.