5 Persimmon Tree Diseases and How to Treat Them
Whether you have a native American persimmon growing in your backyard or planted an Asian persimmon for fruit, it can be alarming to see your tree become discolored or deformed. Join grower Briana Yablonski to learn some common persimmon tree diseases and understand how to treat them.
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One of my favorite things about growing persimmons is their ability to thrive in the humid conditions that plague my Tennessee home. While hot and muggy days lead apple and peach trees to become infected by all kinds of diseases, persimmon trees remain largely unaffected. However, these fruit trees aren’t immune to every plant disease.
Although persimmon trees are quite hardy, they can still become infected by problematic bacteria, fungi, and viruses. These pathogens can lead to concerning symptoms like spotted leaves, rotten roots, and swollen trunks.
In this article, I’ll cover some common diseases that can infect both American and Asian persimmon trees. Along with covering the symptoms to look for, I’ll explain how to prevent and treat each of these diseases.
Anthracnose
Whether you’re growing a small container garden on your patio or establishing a backyard orchard, you’ve probably dealt with anthracnose. Gardeners and horticulturalists use the term anthracnose to refer to a variety of fungal diseases caused by pathogens in the Colletotrichum genus. These pathogens can infect plants ranging from lawn grasses to tomatoes to hardwood trees.
Numerous fungi can cause anthracnose disease in persimmon trees, but Colletotrichum gloeosporioides is the most common causal agent. Infection typically starts in the spring and appears as small spots on twigs and/or leaves. As the weather becomes warmer and more humid, the spots form large lesions that can take over entire twigs and leaves. This leads to overall weakened trees and decreases in yield.
If left untreated, the anthracnose fungi can infect both green and ripe fruits, causing dark lesions. Not only does this lead to ugly fruit, but it also causes the persimmons to drop from the tree before they’re ripe.
Prevention
Since anthracnose thrives in moist, warm environments, keeping the tree dry will help decrease the chances of infection and spread. Always water the base of your tree, and avoid using overhead irrigation. Planting in full sun not only gives the tree the solar energy it needs to thrive, but it also helps morning dew dry quickly.
Regular pruning can help increase airflow and limit the time leaves and twigs remain wet. Prune in the late winter or early spring using a sharp and sanitized pair of pruning shears. Remove any dead, diseased, and broken wood, then remove a quarter to a third of the remaining healthy branches.
If you’re considering adding a new persimmon tree to your property, look for anthracnose-resistant cultivars. While these persimmon varieties aren’t entirely resistant to the disease, they are less susceptible to infection.
When fall arrives, rake up any remaining leaves and twigs that have fallen from the trees. While I often encourage gardeners to leave fallen leaves in place, this does not apply to diseased foliage. Anthracnose can overwinter on fallen leaves and reinfect plants the following spring, so removing the source of infection is crucial.
Treatment
If you notice your persimmon tree is infected with anthracnose, you can try to control the disease with fungicide sprays. However, note that these sprays don’t always effectively control anthracnose. This is especially true if the disease is in its later stages.
Although fungicides aren’t always effective for treating anthracnose, they can help limit the spread of the disease. Spraying your trees with a copper fungicide in the spring can stop the disease from spreading to new parts of the tree. Aim to cover the entire tree every two weeks for the best control.
Prevention is often better than control since it’s difficult to thoroughly spray large trees. If you notice anthracnose on your persimmon tree this year, complete the appropriate measures to prevent infection next year.
Botrytis
Also known as gray mold, botrytis is a fungal disease that can infect many plants. It’s caused by the fungus Botrytis cinerea. The fungus can infect plants as they’re growing and cause fruits to rot post-harvest.
This disease can impact persimmon fruits both before and after harvest. If you notice your persimmons look like they’re covered in a gray fuzz, they’re likely infected with botrytis. While botrytis regularly infects fruits, it can also cause discolored lesions on leaves and twigs.
Botrytis spores germinate best when temperatures are between 55-75°F (13-24°C) and humidity is high. Therefore, this disease is most problematic in the spring and fall. Since the spores can move to plant tissue via splashing water or airflow, plants can easily become infected when the ideal environmental conditions exist.
Prevention
Since the development of botrytis is so dependent on high humidity, keeping plants dry and providing proper airflow can greatly reduce the chances of infection.
Make sure to water the base of your tree rather than the foliage. While you can’t avoid natural rainfall and high humidity, you can take steps to limit the amount of time the tree remains wet. Prune your tree each spring to increase airflow and plant in full sun to speed up evaporation from plant leaves and stems.
If you spot infected tissue, remove it from the plant and dispose of it. Don’t leave fruit on the tree after it has ripened – this is especially important with varieties that have to be snipped during harvesting. You should also clean up any fallen infected fruits, leaves, and stems. Avoid placing these materials in the compost pile; instead, you should trash or burn them.
Treatment
After botrytis has infected a persimmon tree, removing the disease is difficult. In most cases, treatment is unnecessary. Although the fungus may cause some fruits to rot, it rarely impacts the tree’s overall health.
If you’re concerned about botrytis, you can spray a copper fungicide on your trees. Although this spray won’t kill ongoing infections, it will prevent the fungi from spreading to uninfected portions of the tree. Spraying every two weeks is the most effective way to prevent botrytis spread. However, this isn’t a long term solution as botrytis develops resistant to fungicides with frequent usage.
Crown Gall
Crown gall is a bacterial infection caused by the pathogen Agrobacterium tumefaciens. Hundreds of species of plants are susceptible to crown gall, including multiple persimmon species.
Infected trees develop abnormal, rounded growths called galls on their roots and branches. The galls start soft, then turn hard as they age. The infection can impact the movement of water and nutrients, leading to stunted growth and decreased yields. Fortunately, it’s rarely fatal.
The bacteria that cause crown gall typically reside in the soil. They often enter the tree through open wounds and can be spread via pruning tools and insects.
Prevention
Since crown gall is often spread through open wounds, take special care when pruning. Make sure to always use clean pruning shears and loppers, and clean your tools well after each use.
If you’re adding new persimmon trees to your property, thoroughly inspect them before transplanting. Adding infected plants to your home is one of the easiest ways to introduce crown gall.
If you’re worried about crown gall infecting your tree during the transplanting process, you can dip the roots in a beneficial bacterium. The bacterium Agrobacterium radiobacter K-84 protects the roots from infection by the bacterium that causes crown gall.
Treatment
Once crown gall infects your tree, there is nothing you can do to treat it. Large trees can survive infection, but they may experience decreased plant health and fruit yield. New saplings will likely succumb to the disease, so it’s best to remove the tree once it’s infected. Do not compost the tree, but dispose of it.
Leaf Spot
Almost every plant is susceptible to one or more forms of leaf spot. This term refers to spotted foliage rather than a casual agent. Therefore, leaf spots can be caused by bacteria, fungi, and viruses.
In the case of persimmon trees, leaf spot disease is often caused by the fungus Pseudocercospora diospyricola. This fungus can infect them during flowering, leaf formation, and shoot expansion. Therefore, plants are most likely to become infected during the spring and early summer.
Small, dark dots on the leaves are the first sign of infection. Over time, these dots spread and turn into irregularly shaped, dark lesions. Infected leaves often turn yellow and drop from the tree prematurely, around the time that fruit is ripening. Unlike with anthracnose, this disease only impacts foliage.
If the trees become defoliated early enough in the growing season, they won’t be able to capture the energy they need. This may result in stunted growth, reduced yields, and poor fruit quality. Infected plants are also more vulnerable to cold damage.
Prevention
Since poor airflow increases the odds of infection, strive to keep your trees pruned properly. Remove any crisscrossing, dead, or diseased branches that limit airflow within the tree canopy.
You should also remove any diseased leaves and stems that fall to the ground. These materials can harbor the fungi and lead to infections the following year.
If you’re very concerned about leaf spot, you can use fungicides as a preventative strategy. Since infection is most likely to occur around the time the flowers are blooming, spray the tree once at full bloom and again three to four weeks later. Although some extension services recommend synthetic fungicides, you can also try using organic copper fungicides.
Treatment
Once the tree’s foliage is infected, there is nothing you can do to treat the fungus. Fortunately, leaf spot will not kill your tree. Although it may cause defoliation and poor fruits, your tree will survive the winter and regrow the following spring. Treat with a fungicide when the tree is in full bloom and then again 3-4 weeks later.
Persimmon Wilt
While many of the diseases on this list cause ugly foliage and decreased yields, they rarely lead to plant death. Persimmon wilt is different. Once trees become infected by this fungus, they often die in one to two years. Therefore, this disease is a serious threat to persimmon trees.
Persimmon wilt is caused by the fungus Cephalosporium diospyri. The first symptom of this disease is the sudden wilting of the upper leaves. The wilting quickly spreads throughout the rest of the foliage and is followed by complete defoliation. Trees can die within a few months of infection.
When you look at the wood of infected trees, you’ll see it contains fine, dark streaks. After these trees die, pink clusters of spores develop under the bark. These spores then travel with the wind and infect other persimmon trees.
Some people believe Asian persimmon trees (Diospyros kaki) are less susceptible to the fungus. However, these trees can become infected when grafted onto American persimmon (Diospyros virginiana) rootstocks. Native persimmons are highly susceptible to this disease.
Prevention
This fungus often enters trees through open wounds. Therefore, you should try to limit damage to trunks and limbs. Prune in the later winter and early spring to limit chances of infection, and always use clean pruning tools.
If your tree becomes damaged when it loses a limb or becomes hit by a falling tree, don’t leave the wound open to the elements. Although sealing tree wounds isn’t always recommended, it will help prevent persimmon wilt. You can use beeswax or special paint designed to seal cut trees.
If you notice a tree is infected or has died due to persimmon wilt, remove it from your property ASAP. This will decrease the odds that the infection spreads to other trees.
Treatment
Once persimmon trees become infected with this vascular wilt, there is nothing you can do. If you notice a tree is infected, it’s best to remove it before it dies. This will prevent the tree from falling and causing damage and limit the infection of other trees. Remove any remaining leaves and twigs from the ground after removal as well.
