11 Pear Tree Growing Problems and How to Solve Them
Pears are worthy of the home orchard for their bounty of late-season sweet, juicy, flavorful fruits. While relatively easygoing, there are pests and diseases that may target the trees and fruits as they develop. Join gardening expert Katherine Rowe in a look at common pear tree problems and how to treat and prevent them.
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Pears, the lovely historical fruit and hallmark of autumn, are relatively easy to grow in the home garden. Whether dwarf or full-sized trees, they fit seamlessly among ornamental and edible arrangements.
For best fruiting, growing two or more varieties ensures plenty of juicy pears to go around. They’re ideal for creating enticing autumnal fruit bowls and centerpieces in addition to fresh eating, baking, juicing, preserving, and sharing.
While mostly problem-free, some pests and diseases bother the fruiting specimens. Some do little to no damage, while others are more severe if not scouted early. To get the most out of the autumn harvest, know what to look for when it comes to pear tree problems. Here, we’ll explore common offenders, their treatments, and prevention.
Small Fruits
If your tree produces small, hard, and unsweet rounds, it may be due to a lack of thinning. Pyrus and other fruits in good health and with good pollination produce abundant buds after flowering. As the tree uses its energy to support all the buds, there are too many to form fully developed, sweet-tasting, juicy specimens. The excess also weighs down stems and may cause cracking. Pears don’t always need thinning; it’s something to look for in the case of stunted fruits.
An occurrence called “June drop” is common in early summer, where trees naturally drop excess buds as a measure of culling to direct energy to those that remain. Growers sometimes practice manual thinning in late spring to ensure mature fruits.
To thin pears, remove lesser buds when small, about half an inch to an inch. Cut the buds so they’re six to eight inches apart, and reduce the number in clusters to one or two. You’ll still have plenty of pears, just bigger and tastier ones.
Lack of Buds and Fruits
After the burst of fresh spring flowers, we hope to see those little buds form and develop. There are a few things to scout when it comes to a lack of fruit:
- Cultural stress (water fluctuations, poor soil drainage, too much shade, nutrient deficiency, late freezes)
- Pest or disease stress
- Weak cross-pollination
- Not enough chill hours
While some varieties are self-fertile and produce a crop independently, all pears benefit from different varieties growing in the vicinity. Most require cross-pollination with another cultivar for best budset and fruiting. Plant two (or more if you have space) types of pears within 100 feet to attract bees and other insects to pollinate the blossoms.
Pears require a certain amount of chill hours to set fruits. Chill time is at temperatures between 32 and 45°F (0-7°C), and the amount needed varies by species. Asian pears usually require less chill hours and are a good fit for warmer climates, while European varieties require more chill time and grow well in cooler areas. If your area had a warm winter and your variety needs higher chill lengths, poor fruiting may result.
Overfertilizing
Too much of a good thing, like nitrogen, leads to overly vigorous, weak growth. As nitrogen promotes leafy growth and stems, the fast production causes susceptibility to fire blight and other diseases. Excessive amounts also result in fewer fruits as the tree directs energy into foliar growth. Fruits that develop may be small and less sweet.
The best prevention is to use a light hand when it comes to fertilizing. Pyrus adapt to various soil types as long as they’re well-draining. They don’t rely on an overage of nutrients. A single application of an organic slow-release granular in spring is usually enough to span the growing season.
Not Pruning
Trees benefit from pruning to retain form, foster fruiting spurs (new shoots), and maintain vigor. It helps reduce limb breakage and cracking while increasing airflow.
Aim for an oval canopy, a pyramidal/conical shape, or an upright vase shape. These include central leaders with multi-branching for uniform fruiting. Training a young tree with a central leader and side branches promotes good form.
Because of their blight susceptibility, pears don’t require intensive annual pruning, but removing suckers and thinning problem branches is good practice. Remove any crossing, declining, or dead branches at any time of year. Prune for shape in late winter, and cut back whippy suckers as they pop up from the trunk’s base.
Renovating old trees helps increase their yield. Healthy pears are long-lived, and pruning overgrown specimens brings them back to life.
Fire Blight
Fire blight is severe among the genus and also impacts apples as well as ornamentals like quince. The bacterial pathogens (Erwinia amylovora) overwinter in small cankers in the branches and trunk and enter healthy tissues, spreading from the point of infection.
During blooming and in early summer, you may see withered flowers, buds, and blackening leaves and stems that appear scorched and wilted. Branches produce less fruit, and eventually, the entire tree may succumb.
If you suspect blight but aren’t sure, cut into the impacted stem to inspect the tissue. With blight, it will be darkened and moist. If other issues are the cause of the stress, the tissue will be greenish or dry brown.
Treatment
Fungicides or chemical controls aren’t effective at treating fire blight in the home garden. If you spot blight, cut off the impacted growth 8 inches below the last visible signs. Disinfect pruning tools between each cut with an isopropyl alcohol (70% solution) spray or swab, or dip them in a bucket of a half cup of bleach to 5 cups water.
Burn or bag and dispose of the diseased parts, as the pathogens spread easily.
Prevention
Starting with disease-resistant varieties, especially in humid environments, is an important first step. Many good-eating pears feature blight resistance.
Following best cultural practices, like ensuring plenty of air circulation, full sun exposure, and avoiding overfertilizing, create the healthiest specimens.
Also, make sure tools are sharp and clean when pruning. Pathogens enter tissues through small wounds and travel via wind, tools, water, soil, and insects. Avoid pruning in wet conditions.
Leaf Spot
Leaf spot is a fungal infection that grows on leaf and fruit surfaces. Purple-brown spots with lighter centers increase in size and number and spread across leaves and stems. The fungi expand to lesions and cause leaves and stems to blacken.
The spots crop up when leaves stay wet from prolonged moisture. Fabraea leaf spot (Diplocarpon mespili) and Septoria are the main offenders.
Treatment
Early detection is the best control for leaf spot. Cut off diseased leaves and remove any that drop. Prune crowded interior branches where appropriate to increase air circulation. Destroy or discard infected debris away from the garden – leaf spot impacts many selections.
Prevention
Ample airflow is the best defense. Also, water at the ground level to reduce damp conditions among low leaves.
Pear Scab
The fungus Venturia pirina causes dark circular lesions to appear, which become corky and black as the season progresses. Spots appear on fruits, leaf undersides, and stems. Fruit may become inedible as it cracks and deforms.
The spores overwinter and emerge in spring’s wet conditions. Wind and water carry the spores amongst the trees. Infection can cause early leaf and flower drop and premature fruiting.
Treatment
Horticultural oils like neem may provide early treatment. Sulfur is another organic fungicidal control. Be sure to follow application guidelines for effective, targeted use. Prune away infected parts for disposal.
Prevention
Remove debris like dropped leaves, fruits, and twigs from around trunks in the fall. This limits overwintering sites that harbor spores.
Codling Moth
Codling moths (Cydia pomonella) lay eggs on developing fruit surfaces, and the hatching larvae dig into them to feed. Their burrowing and feeding destroy the fruit.
Adult moths are grayish-brown, and the males have coppery scales on their wingtips. The large larvae reach half-inch long and are pink with brown heads.
The mature larvae drop to the ground for cocooning to continue the cycle. There are usually two generations during the growing season, beginning in spring with a reemergence in midsummer. They overwinter in surrounding soils and debris to emerge the following spring.
Treatment
If you have a history of codling moths or live near other orchards, using pheromone sticky traps is a good indicator of their presence. Once you spot the moths, a fruit-safe horticultural oil may help treat infestations, but it is a challenge to target the widespread, flying moths. Targeting the fruit may suffocate the eggs and hatching larvae.
Beneficial nematodes and parasitic wasps prey on codling moth larvae. Apply beneficial nematodes to the surrounding soil during active periods in spring and summer. Plant a diversity of species that attract beneficial insects.
Prevention
Remove infected fruit from the tree to prevent further populations. Removing fallen debris and dropped fruits helps reduce harboring and overwintering by removing sheltering sites.
Aphids
Aphids are sap-sucking insects with soft bodies in pale yellow, green, pink, brown, or black. They colonize in large numbers on the undersides of leaves and feed on tissues.
Aphids prefer soft, new growth, including tender shoots and leaf undersides. They don’t often pose a severe threat but can cause stress. They also leave behind sugary honeydew, leading to unattractive black, sooty mold. Aphids spread fungal spores and are vectors for viruses.
Severe infestation may cause curled leaves, yellowing, and stunted growth.
Treatment
Spraying a strong stream of water early in the day may deter aphids by displacing them from leaves and stems. Do this as part of ongoing maintenance with recurring aphids.
Natural predators are the best line of defense. Attract ladybugs, parasitic wasps, hoverflies, and lacewings with diverse blooming selections.
Aphids congregate in numbers, and pruning off impacted sections may eliminate small infestations. Horticultural soaps or oils like neem control severe infestations. Plant-based insecticidal oils include garlic extract, clove, rosemary, mint, and cinnamon oils and are effective organic controls. Follow label directions, as these treatments affect all insects, including pollinators.
Prevention
To prevent aphids, water consistently to maintain evenly moist soils. Aphids gravitate toward drought-stressed specimens over healthy, well-watered ones.
Spider Mites
Spider mites are another sap-sucking insect that inhabit the undersides of leaves. Their piercing mouthparts feed on cellular tissue. You may not see the tiny creatures without a magnifying glass, but their telltale webbing is a sure sign.
Colonies live around leaf veins and mid-ribs. Females lay eggs and the larvae quickly feed on sap and tissues. Pale spots appear on foliage. Adults feed and produce tight webs around leaves, stems, and branches.
The foliage shows light yellowing and stippling and may become bronze. Leaves become stiff and curl and prematurely drop.
Spider mites occur in hot, dry, dusty conditions. Like aphids, they flock to selections experiencing drought stress.
Treatment
Beneficial predators like ladybugs, lacewings, and predatory mites help control populations. The treatment is the same as for aphids: spray a strong stream of water early in the day to deter and knock insects off the stems. Spraying also rinses away dust.
Prune away affected parts and dispose of debris rather than adding it to the compost pile, which can spread the insects.
Horticultural soap or oil rids the plant of severe cases. Time of day is essential in application, with before or after sunset being the best.
Prevention
To prevent spider mites, water consistently and follow the best cultural guidelines. Water fluctuations give spider mites a chance to increase in number and further weaken plants.
Wildlife
You may experience birds and mammals that enjoy pears as much as we do. Voles, rabbits, and deer may nibble on the soft bark and shoots of young trees. A trunk shield deters small mammals, while a wire cage creates a barrier until branches are beyond reach.
The tasty fruits are a draw for birds, squirrels, and insects. Most European varieties stay green and firm on the branch. Pick these before they ripen for the best flavor. They soften and ripen off the stem. This also makes them less susceptible to predation.
Asian varieties are usually harvested ripe on the stem. If birds and squirrels are a problem, you can net trees post-bloom, after pollination and as buds develop. Fruit bags protect clusters or individual fruits as they mature. Remove and store the nets at autumn’s harvest.
Leave some pears to develop and drop naturally as wildlife forage during the cool season.