Common apricot diseases include brown rot, Armillaria root rot, powdery mildew, Verticillium wilt, Eutypa dieback, and shot hole disease. These fungal diseases tend to occur in moist conditions like humid climates or when overhead watering systems are used.
Treatment with certain organic fungicides, such as copper or Bordeaux mix, can be helpful, but harsh fungicides like sulfur should not be applied to apricot trees. You can also limit disease in apricot trees by pruning for sunlight infiltration and airflow and planting disease-resistant cultivars.
Apricot tree disease basics
Apricot tree diseases are caused by various fungi, bacteria, and viruses that can infect the apricot tree and cause damage to the leaves, fruit, and bark. These diseases can weaken the tree, making it more susceptible to pests and other problems.
If left unchecked, many of these diseases can eventually lead to the demise of the tree (and potentially spread to nearby apricot trees or related fruit trees).
Common apricot tree diseases and their symptoms
Some of the most common apricot tree diseases include brown rot, Armillaria root rot, powdery mildew, Verticillium wilt, Eutypa dieback, and shot hole disease
Brown rot is a fungal disease that affects the fruit of the apricot tree. The symptoms include brown or black spots on the fruit, as well as fuzzy gray growths. This disease can spread quickly and can lead to the death of the apricot tree if not treated. Brown rot fungi can overwinter in mummified decayed fruit and twigs.
Armillaria root rot is a fungal disease that affects the roots of the apricot tree. The symptoms include yellowing and wilting of the leaves, as well as stunted growth. Mushrooms are sometimes visible on the soil surface along the main roots. This disease can eventually kill the apricot tree if not treated. The fungus spreads from other infected roots in the soil, so be aware of previous plantings in your area.
Powdery mildew is another fungal disease that affects the leaves of the apricot tree. The symptoms include white or gray powdery dots or patches on the leaves, as well as stunted growth. This disease can also spread quickly and can cause the apricot tree to produce fewer and smaller fruit.
Verticillium wilt is a fungal disease that affects the vascular system of the apricot tree. The symptoms include wilting leaves, as well as yellowing and browning of the leaves. This disease can spread quickly through the tree and can eventually kill it.
Eutypa dieback is a serious fungal disease that can destroy apricot trees (and occasionally cherries). This fungus kills the tree’s cambium from the inside, causing decaying branches, cankers, dieback, and stunted stems. Eutypa can be spread by rain and sprinklers and thrives in moist growing locations with high air humidity.
Shot hole disease is a fungal blight common in apricots and other Prunus spp. trees like cherries, almonds, plums, nectarines, and peaches. Dark red spots appear on the leaves and twigs of the tree. Like many other fungal conditions, spores are spread by splashing water and thrive in moist, humid environments.
How to treat apricot tree diseases
There are a number of ways to treat apricot tree diseases, depending on the type of disease and the severity of the infection.
Cultural controls are the first way to address disease. Start by pruning off and removing any diseased branches and foliage. You’ll also want to open up the tree canopy to allow for more light and air circulation. Trim off lower branches and any crossing branches. The branches should be sparse.
Switch any overhead sprinklers to drip irrigation and avoid getting the leaves wet if at all possible. Moist foliage encourages the growth of fungal diseases and exacerbates the conditions. This is especially true in humid growing regions.
Prune off and dispose of infected plant tissue as soon as it appears. Inspect trees during all seasons for signs of disease.
Fungal diseases are treated with fungicides, and bacterial conditions are treated with antibiotics. Most apricot diseases are fungal, not bacterial. Specific fungicides work best with apricots, as these trees are quite sensitive to harsh sprays.
Avoid any tree sprays that contain sulfur. While these sprays are common on apple trees, apricots are more sensitive and should not be treated with sulfur. They may become stressed or damaged by the sulfur.
Organic fungicides for apricot trees include Bordeaux spray (copper sulfate and lime), or copper spray. Fungicides can be applied in the fall after leaf drop and removal. Fungicides are generally re-applied in late winter at the end of dormancy, bud swell, and after full bloom.
Disease prevention tips
Prune the young tree into an open center or modified central leader form to allow light into the foliage and promote good air circulation. Avoid dense planting of apricot trees.
Time pruning during summertime when the weather is dry and fungal spore transport is less likely. Pruning can be done in July-August when summers are hot but may have to be limited to August when summers are more temperate (such as in coastal climates).
Select disease-resistant cultivars whenever possible. Some apricot tree varieties are more resistant to certain diseases than others. For example, ‘Harcot’ is resistant to shot hole disease, and ‘Moongold’ is resistant to powdery mildew. Other disease-resistant apricot varieties include ‘Alfred’ and ‘Harlayne.’
“Limit the incidence of brown rot, which results in fuzzy, gray fruits, by picking off dried-up “mummies” that spread the disease the following year and by planting resistant varieties such as ‘Alfred’, ‘Harcot’, and ‘Harlayne’.”
Landscaping with Fruit, by Lee Reich
Before planting, have the young apricot tree inspected by a certified arborist or nursery professional. Make sure the tree is healthy and disease-free.
Plant apricots in well-drained soil with a pH between 6.0 and 7.0. Avoid planting in low spots where water collects.
Water apricot trees at the base of the trunk, not from overhead. Overhead watering can encourage fungal diseases.
Mulch apricot trees with organic materials like wood chips or bark help retain moisture and discourage weeds.
Fertilize your fruit trees with high-quality fruit tree food. Apricots are heavy feeders and need to be fertilized regularly to produce a good crop.
Harvest apricots as soon as they ripen. Don’t wait too long or the fruit will start to rot on the tree. apricots don’t continue to ripen after
Harvest apricots as soon as they are ripe to avoid attracting pests and animals. Remove any fallen apricots from the ground beneath the tree.
Inspect apricot trees regularly for signs of disease. Be on the lookout for cankers, dieback, stunted growth, and leaf spots. Cut off and remove any diseased or dead wood as soon as it is observed (any time of year)
FAQs
Which organic fungicides can be used for apricot trees?
Organic fungicides for apricot trees include copper sprays and Bordeaux mix (copper and lime). Avoid using organic sulfur sprays intended for apple trees on apricots, as they can damage the trees. The best fungicide for apricot trees is one that is specifically labeled for use on apricots.
What causes apricot tree leaves turning brown?
Apricot tree leaves turning brown can be caused by a number of different fungal diseases like Verticillium wilt, Eutypa dieback, leaf spot or powdery mildew. It can also be caused by stress, such as from heat or drought. Ensure the soil is kept consistently moist with drip irrigation and cover the soil surface with 3″ of coarse woody mulch made from composted yard trimmings.
What causes apricot tree leaves drooping?
Apricot tree leaves may be drooping due to lack of water, which can cause the leaves to wilt and droop. Check the soil around the apricot tree to ensure it is moist but not waterlogged. If necessary, water the apricot tree deeply and slowly so the roots have time to absorb the moisture. If leaves are still drooping after watering, investigate for signs of fungal disease.
Can apricot trees get peach leaf curl disease?
Apricot trees can become infected with peach leaf curl. This fungal disease is caused by Taphrina deformans, mainly infecting peaches and nectarines. That said, apricots and almonds are closely related and can also become infected. Peach leaf curl can weaken apricot trees and lead to their demise. Treatment and prevention is similar to those described above.
