Why does the pear fruit turn black
When growing a pear tree, you may notice that the pear fruit turns black. This indicates the development of a dangerous disease called scab. It also affects leaves and shoots, as a result of which the yield of the crop and its winter hardiness decrease, and the quality of the fruits deteriorates.
Why does the pear fruit turn black
The reasons for the development of the disease
The causative agent of scab is a fungus. In the spring, after rainy weather, the wind carries its spores from old leaves to trees. Later, they germinate on fruits and other parts of the pear. Beneficial conditions for this are:
- rainy spring and cool summer - the optimal temperature for the development of the pathogen is 19-25 ° C, but the process is possible even at rates of 2-3 ° C;
- high air humidity.
Disputes may dissipate until July. But mass reproduction occurs before the flowering of the crop, in the period between the opening of the leaves and the formation of buds.
In hot and dry summers, trees may not be affected by disease. But the risk of activating the fungus exists when abundant dew falls. They, like rains, determine the humidity of the environment.
Symptoms of the disease
After the defeat, the scab appears after 2-3 weeks. It is important to identify it at an early stage. The disease is accompanied by the following symptoms:
- black spots on fruits with a velvety bloom - the flesh under the damaged areas becomes loose, in these places after a while cracking of tissues occurs;
- rounded green-olive spots on the leaves, which are invisible at first, but then darken;
- deformation of fruits - their appearance loses its presentability;
- falling off of affected leaves, ovaries, pears.
If the infection occurred in the spring, then the spots on the leaf plate are large. If later - small. Sometimes the scab attacks the crop before harvesting. Then the black dots are hardly noticeable, but appear during storage of the fruit.
When shoots are damaged, the bark becomes covered with small bubbles, in which the mycelium of the fungus develops. The bulges crack over time due to the pressure of the conidia. The surface begins to peel off. Flowers, stalks, cuttings are also exposed to the disease.
Treatment of the disease
It is possible to avoid pear diseases
Black fruits, leaves and other affected areas of the pear are removed and burned. To prevent the development of the disease, it is necessary to spray the tree with medicinal preparations at a certain time. The event is performed in dry, calm weather. If it rained immediately after that, the steps must be repeated.
Bordeaux liquid
The first time the plant is treated before bud break. To do this, use a 3% Bordeaux mixture. The next spraying is carried out every 2 weeks, since the effect of the agent remains during this period. The concentration of the substance is reduced to 1%. Up to 6-7 treatments are carried out per season. Instead of Bordeaux liquid, you can use a 3% solution of copper sulfate.
Fungicides
Systemic drugs are effective in the treatment of scab:
- Fast - the product is used up to 2 times throughout the season: before flowering, after flowering. For this, 2 ml of the substance is dissolved in 10 l of water. The processing action is up to 20 days.
- Strobi - the drug is used in 3 stages. The interval between spraying should be 2 weeks. The dosage is determined according to the attached instructions. Effective for 35 days. Can be combined with other products.
- Horus - processing is carried out 2 times per season: during the budding period, at the end of flowering. Gives good results at low temperatures (3-10˚C). Validity period - 1 month.
Mineral fertilizers
If the leaves and fruits turn black on the pear, it should be fed. This procedure helps fight scab and also serves as a foliar fertilizer. Apply solutions of mineral agents. For 10 liters of water, take one of the following drugs:
- ammonium nitrate - 10 g;
- ammonium sulfate - 10 g;
- potassium chloride - 3-10 g;
- potassium sulfate - 3-10 g;
- potassium nitrate - 5-15 g;
- potassium salt - 5-15 g.
Combining drugs
If the fruits turn black at the later stages of plant development, then the best treatment will be the complex use of drugs. They are used according to the following scheme:
- After harvesting, foliar fertilizing is performed with mineral agents. The air temperature must be above 4 ° C. The procedure helps to increase yields, and also acts against various pests.
- In the spring, before flowering, the tree and the trunk circle are sprayed with Bordeaux liquid or a solution of copper sulfate.
- After flowering, the plant is treated with a fungicide.
Disease prevention
You can prevent the development of scab by taking the necessary measures. Prevention begins even before planting a seedling. To do this, they act on the following principles:
- choose a place that meets the requirements of the fruit tree;
- plant varieties resistant to the disease: Bere Gardi, Bere Bock, Lyubimitsa Klappa, Vrodlyva, Zolotovorotskaya, Etude, Vyzhnitsa, Tavriiskaya, Trembita, Stryiskaya, Margarita, etc .;
- do not thicken plantings.
After planting a tree, preventive measures are as follows:
- cleaning of fallen leaves;
- correct feeding throughout the season;
- treatment of trees after harvest with Bordeaux liquid or other medicinal preparations.
The most susceptible to the disease are the following types of culture: Forest Beauty, Ilyinka, Bergamot Milevsky, Winter Bere Ligel, Sapezhanka.
Conclusion
If the pear fruit turns black, it is worth examining the plant for symptoms of scab. Timely control measures will help protect your crops from damage. If you don't start treatment, you can lose all the fruit. Preventing the disease will prevent unnecessary worries. It is also worth paying attention to other fruit trees in the garden, which can serve as sources of fungi.