10 Reasons Why Pears Rotting on the Tree and 5 Ways to Treat It

Why do pears crack and rot on the tree so often, even before ripening? The culprit is a widespread fungal disease called moniliosis (fruit rot). In favorable conditions, it destroys up to 80% of the crop. There are many causes for this disease, and we'll explore each one and describe how to eliminate it.

Causes of rot on pear fruits

The disease is dangerous because signs of damage only become visible when the fruit begins to ripen. Small brownish spots appear on the skin, which quickly spread and can cover the entire fruit within 7-10 days.

On affected areas of the fruit, yellowish-white or dark gray cushions form in concentric circles, where fungal spores are clearly visible. Often, individual severely affected pears remain hanging on the tree. Through the petiole, these spores infect the fruiting branches, which dry out, and the fungus will subsequently overwinter within.

Rot can also damage skeletal branches. Distinct, sunken spots appear on the bark surface, eventually encircling the branch, leading to complete desiccation of its upper portion.

What factors lead to rotting of unripe fruits:

1. Old varieties bred from wild pears are genetically predisposed to rot. The problem is not caused by a disease, but by the process of optimally preparing the seeds for germination. It's easy to distinguish a varietal trait from the development of the disease: in pears bred to this type, rot begins at the stem, and by the time they're fully ripe, the rot has spread to most of the core.
2. The fungus that causes moniliosis can enter the fruit through various skin lesions caused by wasps, birds, hail, or other diseases. Healthy pears become infected through contact with the diseased fungus.
3. Spores are spread by wind and insects. Pests leave numerous traces on fruits and other tree parts during their life cycles, and all affected areas serve as entry points for fungal spores.
4. The best conditions for rot development are high humidity (over 75%) and warm weather (24–28°C). The risk of moniliosis is highest during rainy summers.
5. Spores are destroyed by direct sunlight, so another cause of rot is dense canopies or dense plantings of garden crops. Tree branches are poorly ventilated, creating conditions of high humidity.
6. When pears are infected with scab, deep cracks covered with a rough crust appear on the fruit. Scab does not cause the fruit to rot, but as the disease progresses, it creates favorable conditions for infection by moniliosis.
7. The fungus overwinters in plant debris and tree bark (where unusual darkening is visible). If fallen leaves, branches, and fruit are not removed, especially from diseased trees, the fight against moniliosis will be protracted, and rot will become a constant occurrence.
8. Strong trees are able to resist fungal attacks, but those with weakened immune systems are more susceptible to attack. Tree health is often affected by a deficiency of macro- and micronutrients in the soil.
9. The fungus is very resilient and can withstand severe frosts. However, the most severe outbreaks of fruit rot have been observed in years with mild winters.
10. Another risk is infestation of neighboring trees. While this problem is easy to solve in your own garden, it's more difficult for those whose property is located next to unkempt or neglected gardens.

Moniliosis (moniliosis) in pears is a consequence of inadequate or improper tree care, and this problem can be resolved. For older pear varieties, where fruit rot is genetically predisposed, the only way to save the harvest is by harvesting unripe fruit and ripening it at home.

How to cure pear fruit rot and prevention

Fruit rot treatment should be comprehensive. Treatment for moniliosis, as well as scab, should begin in the same season as the first signs of disease are noticed; delaying treatment until spring is highly undesirable. When most of the fruit is covered with spots, the entire crop is harvested and sorted. Any remaining pears should be eaten as quickly as possible or processed (for compotes, jams, and other winter preserves). All rotten fruit should be removed from the garden. Let's begin treatment:

1. Before frost, apply one treatment with a 1% Bordeaux mixture and two sprays with Abiga Peak. Moniliosis affects almost all stone fruit crops; it's also advisable to treat them, but only after all the fruit has been harvested. The interval between treatments can be adjusted individually. Before leaf fall, pears are sprayed with a 5 or 8% urea solution.
2. Immediately after the leaves fall, all plant debris is removed from the orchard and burned. Any dried pears remaining on the tree are also picked. Old or infected bark is scraped from the trunks and skeletal branches. The soil around the trunks is dug over. The final step in preparing the pear trees for winter is whitewashing the trunks.
3. In the spring, before the sap begins to flow, dry, damaged branches and shoots are pruned, the crown is thinned, and then the trees and soil are sprayed three times with protective fungicides. The first treatment is before bud break, the next immediately after flowering, and the last two weeks later. Many gardeners successfully use Bordeaux mixture; for the first spray, they prepare a 3% solution, and for subsequent sprays, a 1% solution.
4. Don't neglect pest prevention, especially for caterpillars, codling moths, aphids, and weevils. Sprays should be applied from early spring until almost harvest time. Products such as Fufanon, Aktara, Confidor, Decis, and ZOV have shown good results. Depending on the insect species and the extent of the tree infestation, you may need to choose a different product.
5. During the growing season, another 2 or 3 sprayings of copper-containing products should be carried out. During the period of fruit formation and ripening, chemicals can be replaced with biological products such as Fitosporin, Fitolavin, Mikosan, or Alirin. A month before harvest, use a pharmacy solution: 10 ml of iodine per 10 liters of water (two treatments, 3 days apart).

How to replenish the deficiency of useful elements

Once per season, pear trees showing signs of nutrient deficiency (poor tree growth, smaller fruit, pale leaves) are sprayed with a special solution. A general recipe for 10 liters of water:

• 100 grams of urea;
• 5 grams of copper sulfate;
• 3 grams of boric acid and potassium permanganate.

These products can be used in tandem with pesticides, and can be used simultaneously for protective treatments. The solution is quickly absorbed by the leaves, stimulating and controlling the tree's key life processes, and improving the absorption of available nutrients from the soil.

Agrotechnical techniques, useful tips

The first thing to do if you discover slightly rotten pears is to remove them from the tree. Pick off all damaged fruit (cracked, scratched, etc.). Fallen fruit should be removed throughout the growing season. Damaged fruit, especially those with scab or moniliosis, should not be placed in compost piles.

Throughout the summer, keep your garden clean, removing all weeds, fallen branches, and leaves. When working with trees, use only thoroughly cleaned and disinfected garden tools. Treat pruning wounds and bark removal with garden pitch or special paint.

During rainy periods, loosen the soil around the tree trunks whenever possible and ensure adequate drainage. During dry, hot summers, the disease usually doesn't manifest itself, but there are exceptions associated with "stress cracking." If the soil is watered generously after a long drought, the dehydrated pear flesh will quickly become saturated with moisture, and the skin won't have time to catch up.

The fungus penetrates the resulting cracks, and within 2 or 3 weeks, fruit rot will spread throughout the entire tree. During hot weather, keep the soil moist and evenly moist, and be sure to apply a layer of mulch not only around the trunk but also under the entire crown.

To repel various pests without resorting to chemical treatments, create small beds in your garden with chamomile, wormwood, calendula, and tansy. If pests have already appeared, these same herbs can be used to make decoctions and infusions for spraying.

Pear varieties resistant to fruit rot

There are no completely resistant pear varieties, but there are some that have fairly good immunity to all fungal diseases, including scab. Let's highlight the best of them:

• Aurora (Lyubina);
• Winter bere Michurin;
• Conference;
• Curé;
• Krasnodar summer;
• Summer Sergeeva;
• Radiant;
• Lyre;
• Moldavian early;
• Honey;
• October;
• Autumn dream;
• Roxolana;
• Saint Germain;
• Trembita.

The varieties most severely affected by fruit rot are Sapezhanka and Dekanka Zimnyaya. No magic cure has yet been invented to eradicate the disease in a single treatment. It's impossible to eradicate the disease completely, as the fungus is spread by birds, wind, and insects. Combating the rot requires a series of ongoing preventative measures, carried out from early spring to late fall.