Do You Have Spots On Pears – Learn About Bitter Rot On Pear Trees
Fruits with soft, necrotic spots may be victims of bitter rot on pear. The disease does not need injury to penetrate the fruit, and it can attack young fruit but is most prevalent on maturing pear trees. Pears with bitter rot will become inedible which is a huge concern in commercial production. Learn how to prevent bitter pear rot in your plants.
What Causes Bitter Pear Rot?
Few things are as delightful as a fresh, ripe pear. Spots on pears may be a symptom of bitter rot, a disease of apples, pears, peach, quince, and cherry. Various conditions affect the development of the disease including temperature, tree health, site, and soil. Bitter rot on pear affects only the fruit and generally occurs during the hottest periods of the growing season. There are several cultural and hygienic steps you can take to prevent pears with bitter rot.
The causal agent is a fungus, Colletotrichum gloeosporioides (syn. Glomerella cingulata). It overwinters in fruit mummies, cracked bark, dead plant material, and cankers. The spores are spread by birds, rain splash, wind, and possibly insects. The disease really gets going when conditions are rainy and temperatures are 80 to 90 degrees F. (27-32 C.). When hot, muggy weather occurs late in the season, an epidemic of the fungus may occur. In orchards the disease can spread rapidly from tree to tree, causing huge economic loss.
It only affects fruit, although occasionally some cankers will form on tree bark.
Symptoms of Bitter Rot on Pear
Symptoms are generally observed in late summer. The fungus is one of the few that can penetrate the skin of the fruit without an entry wound. The first signs are small, round brown spots on fruit. If temperature and humidity are high, the spots rapidly enlarge. Once the spots become ¼ inch (6 mm.), they begin to sink in and have a saucer shape.
Once the spots are ½ inch (1 cm.), the fruiting bodies appear. These are tiny black spots in the rotting center of the spot. Pears with bitter rot then begin to ooze a pink, gelatinous substance that leaks and soaks down onto lower dependent fruits. The fruit will continue to decay and eventually shrink into a mummy.
How to Prevent Bitter Pear Rot
The first steps to avoiding fungal spots on pears is to clean up the area after the harvest period. Remove any mummies on the ground and those clinging to the tree.
If there are wounds to the tree, treat them with fungicide or cut damaged limbs back to healthy material. Remove any pruned wood from the area.
Provide good care including fertilizer, water, and pruning to encourage healthy growth and a vigorous tree.
During the growing season, apply a fungicide every 10 to 14 days to manage the disease. In organic situations, good sanitary practices and care are the best preventatives.
Fact Sheet: Bitter Rot
What is bitter rot?
Bitter rot is a common fruit rotting disease of apple (and pear). It is caused by the fungi Colletotrichum gloeosporiodes and C. acutatum . The same pathogens also cause anthracnose fruit rot in peach, blueberry, and strawberry. The sexual phase of C. gloeosporides is called Glomerella cingulata and can also cause fruit rot and leaf spot disease on apples. Disease development is favored by high temperatures (80–90 ° F) and high relative humidity (80–100%). The fungus can directly penetrate into fruit skin without prior injury.
What does bitter rot look like?
- Symptoms first appear as small, slightly sunken circular areas arranged in concentric rings that are light to dark brown in color and advance to dark brown with small black dots.
- Symptomatic areas in fruit ooze a gelatinous, salmon-pink mass of spores.
- As the lesions enlarge, the rot progresses to the core of the fruit in a V- or cone-shaped pattern.
- As the fruit ripens, it decays rapidly and finally shrivels into a mummy.
- Bitter rot usually appears on the sun-exposed surfaces of fruit, and heat injury or sub-lethal sunburn may increase susceptibility of fruit to this disease.
Where does bitter rot come from?
The fungus survive the winter in dead wood, cracks in the bark, or mummified fruit that were infected during the previous season. Conidial spores are spread by splashing and wind-blown rain, insects and birds while ascospores are released into the air during rainy periods. Insects can spread the fungus from infected fruit to healthy fruit.
Pears grow in most areas of Mississippi. In the southeastern United States, pears grow better if they have some resistance to diseases like fire blight and leaf spot.
Most pear varieties are self-unfruitful (self-sterile). Plant at least two varieties with similar blooming periods (early, mid-, or late season) for cross-pollination. To avoid frost damage, plant low chill, early blooming pears only in extreme south Mississippi. Most pear fruit is better if picked before maturity and allowed to ripen off the tree at 70 °F.
- Kieffer is the most commonly grown pear in the South and is well adapted to Mississippi. This old variety has little resistance to fire blight. Considered an early to mid-bloomer. May suffer late-frost damage. The Kieffer pear matures in late September or October. Good for preserves.
- Orient produces large, somewhat round pears that ripen mid-August to early September. The tree is vigorous, spreading, shows some resistance to fire blight, and is well adapted throughout the state. Good for canning. The blooming period is mid- and late season.
- Moonglow is a spur-type tree that is vigorous, blooms late, and has good fire blight resistance. Fruit quality is good with a mild flavor, few grit cells, and soft flesh good for canning. Fruit ripens in mid-August.
- Ayers trees are vigorous, upright, and blight resistant. The chilling requirement is high. Ayers is recommended for north Mississippi only. The fruit is an attractive yellow with red blush and ripens in late July to early August. The blooming period is early.
- Baldwin is an excellent variety for Coastal areas because of its low chill hour requirement. The fruit is almost round and golden yellow when ripe. Bloom period is early. Ripens in mid-October.
- Maxine has less resistance to fireblight than does Magness or Moonglow. The trees are vigorous and upright. Maxine is a good pollinator for Moonglow or Magness. It ripens in mid-September between Orient and Kieffer. Fruit quality is good.
- Magness is high quality. Requires 5 to 6 years before fruit bearing begins. High resistance to fire blight. Ripens in late August. Magness does not produce good pollen.
- LeConte is adapted to North and mid-Mississippi. Good resistance to fire blight. Fruit is yellow with red blush. Excellent for eating.
What to do with pears after picking?
Here are 11 recipes that are perfect if you're wondering what to do with overripe pears.
- Freeze for Smoothies.
- Pear Jam.
- Pear Crumble.
- Mash Into a Pancake Topping.
- Blend Them Into a Salad Dressing.
- Bake Into Fruit Leather.
- Pear Ice Pops.
- Vanilla Spiced Pear Butter.
Also, how do you harvest and store pears? To speed up ripening, place the pears in a tightly sealed paper bag. The fruit give off ethylene gas, which accumulates in the bag and promotes ripening. For long-term storage, refrigerate unripened pears at a temperature of 32 to 35 degrees Fahrenheit. European pears may be stored for one to three months.
Also Know, how do you ripen pears after picking?
Add ripe bananas or apples to the paper bag to ripen pears in 1-3 days. To produce ripe pears in just 1-3 days, place a banana or apple in the paper bag with your pears. The ripe fruits give off ethylene gas, which causes the pears to ripen very quickly.
When should Pears be picked?
Pears should be harvested when fully formed, but not ripe. Most years that time is early August for Bartletts, but this year everything seems to be early, so it's important to watch your pears for when they are mature.
Common Diseases on Plums
The fungal disease, black knot, can occur on branches of cherries and especially plums. This is most common when these fruit trees are grown near wooded areas that contain wild cherry. Pruning out these knots as soon as observed and spraying a fungicide such as BENLTATE starting early bloom with 2 to 3 additional sprays 7 to 10 days apart can aid in reducing black knot. The disease most commonly encountered on cherries and plums is brown rot. Apply the first combination spray when the flower petals begin to drop and repeat at 2 to 3-week intervals until 3 weeks before anticipated harvest. If weather conditions are wet, apply 1 to 2 fungicide (myclobutanil) sprays as recommended for peaches during the 3-week preharvest period to reduce brown rot.
The peach tree borer can cause serious damage on the trunks of peach, nectarine, cherry, and plum trees. Damage caused by this insect can lead to tree death. To control peach tree borers, apply endosulfan 50W (Thiodan) at the rate of 2 tablespoons per gallon of water (7 oz per 10 gallons) to the lower limbs, trunk and base of the tree the first week in September.