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Pear Tree Diseases And Treatment: Diagnosing And Treating Disease In Pears

Pear Tree Diseases And Treatment: Diagnosing And Treating Disease In Pears


By: Liz Baessler

Home-grown pears are really a treasure. If you have a pear tree, you know just how sweet and satisfying they can be. Unfortunately that sweetness comes at a price, as pear trees are susceptible to quite a few easily spread diseases that can wipe them right out if left untreated. Keep reading to learn more about pear tree diseases and treatment.

Common Diseases of Pears

There are a few very common and easily identifiable diseases of pears. Of these, fire blight is the worst, as it can spread very rapidly. It appears as cankers that leak out a creamy ooze on any or all parts of the tree, blossoms, and fruit. The area around the canker takes on a blackened or burned appearance, hence the name.

Fabraea leaf spot, leaf blight, and black spot are all names for a spread of brown and black spots that form on the leaves late in the summer and cause them to drop. The spots can also spread to the fruit.

Pear scab manifests itself as soft black/green lesions on the fruit, leaves, and twigs that turn gray and crack with age. Outbreaks occur once in early summer and again in mid-summer.

Sooty blotch appears as black smudges on the skin of the fruit. Be on the lookout for sick looking pear trees, especially during wet spells, as most types of pear tree diseases appear and spread during periods of rain and high humidity.

How to Treat Sick Looking Pear Trees

The most effective method for treating disease in pears is the sanitation and removal of all affected parts of the tree.

If your pear shows signs of fire blight, cut away any branches exhibiting symptoms 8-12 inches (20.5-30.5 cm) below the canker, leaving only healthy wood. After each cut, sanitize your tools in a 10/90 solution of bleach/water. Take the removed branches far from your tree to destroy them, and monitor your tree for any new cankers.

For both leaf spot and pear scab, remove and destroy all fallen leaves and fruit to greatly reduce the risk of the disease’s spread into the next growing season. Apply a fungicide throughout the next growing season as well.

Sooty blotch affects only the appearance of the fruit and will not harm your tree. It can be removed from individual pears with scrubbing, and the application of fungicide should curb its spread.

Since these diseases spread through moisture, a lot of preventative work can be done simply by keeping the surrounding grass short and pruning the tree’s branches to allow for air circulation.

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How to Stop Rust on a Pear Tree

Pear rust, also known as pear trellis rust, is a fungus spread by wind-blown spores. Both juniper and pear trees suffer from this fungal disease, and they spread it rampantly to each other when the two types of trees are planted close to one another. Pear rust is most common in Europe, on southern Vancouver Island, in one county in California and in one area of Washington State. Rust is difficult to stop, especially if your neighborhood has a lot of junipers and pear trees planted close enough to each other that the spores can spread through the air. There are some preventive measures you can take, however, to stop pear rust.

Determine whether pear rust is indeed your culprit. You should see orange spots covering the leaves in early summer, changing to fuzzy growth in autumn. In mid-summer, the orange spots will develop black spots, and then the spores will produce structures that erupt from the leaves’ lower surfaces.

  • Pear rust, also known as pear trellis rust, is a fungus spread by wind-blown spores.
  • In mid-summer, the orange spots will develop black spots, and then the spores will produce structures that erupt from the leaves’ lower surfaces.

Plant juniper trees as far away from your pear trees as possible. Make sure the junipers and pear trees are at least 100 feet apart, as this will prevent the spread of rust from the junipers to the pears. The rust fungus will over-winter on juniper trees.

Remove the nearby infected junipers in early spring to contain the spread of the fungus and damage to your pear trees. Be sure to remove from your yard all parts of the tree that you’ve cut down.

Pick off the infected leaves on your pear tree in the spring and early summer every year. This will help to prevent spreading the disease to your neighbors’ junipers.

  • Plant juniper trees as far away from your pear trees as possible.
  • Remove the nearby infected junipers in early spring to contain the spread of the fungus and damage to your pear trees.

Prune any infected pear trees frequently, cutting out any growths at the base of the twigs. These growths on severely infected pear trees are an unstoppable source of infection in the tree.

If you have neighbors nearby, talk with them to find out if they would remove their juniper trees to stop the spread of the rust on the pear trees. Chances are if your neighbors are close enough, they’re having rust problems as well.

You don’t need to worry about the disposal of leaves that you remove from an infected tree. After picking the infected leaves, the fungus will simply die after a few days.

Don’t bother to use fungicide sprays on your pear trees. These sprays are not usually effective on rust.


Signs and Symptoms

The first signs of fire blight in Bradford pear trees appear in early spring, when the weather is rainy and temperatures have warmed to above 60 degrees Fahrenheit during the day and 55 degrees at night. The infection appears first at the stem tips, where the leaves curl and blacken and the twigs bend sharply like a shepherd's crook. As the disease progresses down the branches, weeping cankers form on the bark, and entire branches begin to die back. The bark immediately surrounding the cankers is brown with light red flecks radiating out from the outer edges.


8 Common Fruit Tree Issues & How to Treat Them Organically

Sooty Blotch/Flyspeck

Affects: apple trees, pear trees

Grayish-black soot-like splotches and/or tiny black specks. Sooty blotch usually shows up in late summer or fall, and is encouraged by normal temperature ranges combined with high humidity. Blotch and flyspeck are not rots they appear only on the fruit’s surface.

Treatment: First, proactively keep your trees pruned so air can properly circulate. This alone will act as a preventive measure. If this condition appears, you can scrub the surface of the fruit using just water and a little elbow grease. It may not get the skin perfectly spotless, but it cleans off most of the sooty blotch and flyspeck. Alternatively, Serenade Disease Control is effective.

Bitter Rot

Affects: apple trees, pear trees, cherry trees

Not at all uncommon during hot, humid weather. Concentric rings of spores form on the fruit, leading to a foul-smelling rot. The V-shaped sunken spots usually penetrate to the fruit’s core.

Treatment:Revitalize Bio Fungicide or a sulfur-based spray. Remove diseased fruit from branches and prune off any cankers found on tree limbs. Contact your local county horticultural extension for advice that’s specific to your growing area.

Black Rot

Affects: apple trees, pear trees

Black rot is a particular problem in the Southeastern states, and with grapes. Leaves will display a target-like leaf spot as the season progresses, dark rot will become visible on the fruit bottom in rings, which eventually turn the fruit completely black.

Treatment: Revitalize Bio Fungicide. Prune out dead wood and remove fallen debris under trees and grapevines. . Contact your local county horticultural extension for advice that’s specific to your growing area.

Scab

Affects: apple trees, peach trees

Black, scab-like spots on both fruit and foliage. Cool, wet weather provide prime conditions for scab. If you spot scab, it must be treated throughout the season to prevent crop failure. Choosing a scab-resistant variety is the best prevention.

Treatment: Serenade® Garden Disease Control (for Apple, Cherry, and Walnut trees) or a sulfur spray. Rake and destroy fallen leaves to reduce the amount of disease that will carry over to the next year. Contact your local county horticultural extension for advice that’s specific to your growing area.

Brown Rot

Affects: apricot trees, cherry trees, peach trees, plum trees, nectarine trees

Brown rot infects stone fruit blossoms, stems and fruit. During summers with higher-than-average rainfall, young fruit that is damaged by insect chewing will develop this condition.

Treatment: Bonide® Copper Fungicide. Remove and/or prune infected tissues and areas on trees. Remove and discard any mummified fruit. You can also experiment with this technique: Get the area as dry as possible, thin out about 1/3 of the leaves, then lightly sprinkle dry powdered milk on the remaining leaves. Contact your local county horticultural extension for advice that’s specific to your growing area.

Gummosis

Affects: peach trees, nectarine trees, plum trees

Gummosis causes lesions or “sores” with a thick, oozing orange gelatin-like resin on the trunk, limbs and/or twigs. Young branches may be killed if the condition is allowed to advance.

Treatment: Monterey Fruit Tree Spray Plus. Prune away dead wood and water during dry spells to reduce stress on the tree. Contact your local county horticultural extension for advice that’s specific to your growing area.

Peach Leaf Curl

Affects: peach trees, nectarine trees

Peach leaf curl presents itself in cool weather, affecting leaves and shoots of new leaves. Look for red spots about two weeks after leaves emerge, then white spores will appear. Leaves will yellow and fall off, and new leaves will emerge. This does not mean the tree is now healthy. For successful control, apply fungicide in early spring before bud swell and/or starting in the late fall after leaves have dropped. Applying fungicide after symptoms appear in leaves will not be effective.

Treatment: Bonide® Copper Fungicide or Monterey Fruit Tree Spray Plus. Contact your local county horticultural extension for advice that’s specific to your growing area.

Cherry Leaf Spot

Affects: cherry trees

Sometimes called "shot hole". Yellow, irregular-shaped spots appear near the top of fruit with a light gray mold on the lower leaf surface. The disease will survive winter and reappear, so remove all leaves in the fall. The University of Nebraska recommends a fungicide treatment at petal fall, shuck fall and again two weeks later.

Treatment:Bonide® Copper Fungicide or Serenade® Garden Disease Control (for Apple, Cherry, and Walnut trees). Contact your local county horticultural extension for advice that’s specific to your growing area.


Fruit Tree Pests & Diseases

Growing fruit is an enjoyable and rewarding past time, however even the most avid and vigilant of gardeners may occasionally encounter a problem. To help you tackle any challenges posed by mother nature we have put together a range of fact sheets that will assist you in the fruit garden with pest and disease management.

The following tables have been designed to aid diagnosis and treatment of common fruiting problems. We hope to update it as more information becomes available.

Click here for information on soft fruit pests and diseases.


Apple and Pear Pest, Diseases and Disorders


Apricot Pests, Diseases & Disorders

Leaf distortion/marking on leaves

Cobnuts & Filberts Pests Diseases & Disorders

Squirrels are the most serious pest since they can quickly devour a whole crop. Netting is usually ineffective as they can chew through it. Galvanised wire netting is effective but can lead to problems of zinc toxicity. The fruits can be attacked by Nut Gall Mites, Nut Weevils and Winter Moth larvae. The trees are generally free from disease.


Figs Pest, Diseases & Disorders

Squirrels and birds are the most serious pests. The trees are generally free from disease but occasionally suffer from Coral Spot (dead twigs become covered in pink pustules). Disease twigs should be cut back to a healthy bud and the prunings should be burned.


Peach, Nectarine & Almond Pests, Diseases & Disorders

Leaf distortion/marking on leaves


Plum, Gages, Damson & Cherry Plum Pests, Diseases & Disorders

Leaf distortion/
marking on leaves


Quince & Medlar Pests, Diseases & Disorders

Leaf distortion/
marking on leaves

Sweet Chestnuts & Walnut Pest, Diseases & Disorders

The sweet chestnut is relatively free from pests and diseases. Most pests of walnuts, including the Walnut Leaf Gall Mite, are not too serious and can cause mostly cosmetic damage. Walnuts are susceptible to some diseases including Walnut Blight, Walnut Leaf Blotch , Honey Fungus and Grey Mould .


Click here for information on soft fruit pests and diseases.


USING CHEMICALS SAFELY – ALWAYS READ THE LABEL

When using chemicals it is most important to follow the manufacturer’s instructions precisely. Only use on the fruits that are listed on the manufacturer’s label. An accurate weighing machine and measuring cylinder should be obtained. Chemicals can be wasted by making concentrations unnecessarily strong or by making them too weak and ineffective. Furthermore, if chemicals are too strong they may cause damage to the foliage.

Only spray in the early morning or evening when the weather is dry and calm. Avoid spraying when fruit canes and bushes are in flower, to reduce the risk of killing helpful pollinating insects such as bees.


Stony Pit Virus

If you see damaged fruit together with lumps and 1/4-inch pits in a pear tree, the stony pit virus may be to blame. This virus spreads through the grafting process, when infected wood is grafted onto a healthy tree. Stony pit virus is relatively uncommon in pear trees on the whole, with Anjou or Bosc pear trees being the most susceptible. Pear fruits from an infected tree are usually inedible. You can control the virus by pruning and destroying the infected areas of the tree. A severe viral infection can kill a pear tree.

Jae Allen has been a writer since 1999, with articles published in "The Hub," "Innocent Words" and "Rhythm." She has worked as a medical writer, paralegal, veterinary assistant, stage manager, session musician, ghostwriter and university professor. Allen specializes in travel, health/fitness, animals and other topics.


Watch the video: How to Treat u0026 Prevent Fire Blight in Your Organic Orchard