Diseases and Pests that Most Affect Trees and How to Protect Them

Just like people, trees can also suffer from diseases that affect their growth and vitality. That is why it is important to keep them in good condition and protect them from these diseases and from pests, another evil that also frequently attacks them.

This article explores the main threats facing trees and provides effective strategies to protect them.

Main Tree Diseases

Mildew (Peronospora spp.)

Mildew is a fungal disease that affects many tree species, especially fruit trees. It manifests as yellow spots on the leaves, which eventually turn brown and fall off. In severe cases, it can affect fruit production and weaken the tree.

Prevention and Control: To protect trees from mildew, it is essential to improve air circulation through proper pruning. In addition, the use of specific fungicides can help control the disease in severe cases.

Bark canker (Cytospora spp.)

This disease primarily affects deciduous trees. It presents as spots or wounds on the bark, which can lead to loss of branches and ultimately death of the tree.

Prevention and Control: Maintaining good garden hygiene, removing dead branches and applying sealants to bark wounds, can prevent the spread of the fungus. Proper fertilization also contributes to the overall health of the tree, making it more resilient.

Rusts (Puccinia spp.)

Rusts are fungi that affect a wide variety of tree species. They manifest as orange or yellow spots on the leaves. Although they may not be fatal, they reduce photosynthesis and weaken the tree.

Prevention and Control: Crop rotation and selection of resistant varieties are effective strategies. The use of fungicides may also be necessary in cases of severe infestations.

Main Pests Affecting Trees

Aphids (Aphidoidea)

Aphids are small insects that feed on tree sap. Their presence can lead to leaf deformation and the transmission of viruses.

Prevention and Control: Maintaining a healthy ecosystem with natural predators, such as ladybugs, is a good strategy. In severe infestations, specific insecticides can be used to control them.

Pine weevil (Dendroctonus spp.)

These beetles bore into the bark of pine trees, weakening them and, in many cases, causing their death. Their proliferation can be exacerbated by water stress and high temperatures.

Prevention and Control: Constant monitoring is key. Pruning and keeping the tree well hydrated is recommended. In severe infestations, it is best to turn to a professional for treatment.

3. Caterpillars (Lymantria dispar)

Caterpillars, especially the pine processionary moth, can eat large amounts of foliage, weakening the tree and making it susceptible to other diseases.

Prevention and Control: Constant monitoring of trees is essential. The use of traps and manual removal of caterpillars can be effective. In severe cases, insecticides can be applied.

General Strategies for Protecting Trees

• Species Selection: Choosing tree species that are native and adapted to local conditions can increase resistance to diseases and pests.

• Proper Maintenance: Performing regular pruning, cleaning the surrounding area, and applying appropriate fertilizers are practices that strengthen tree health.

• Proper Irrigation: Providing the right amount of water, especially during times of drought, is essential to maintaining tree health. Avoiding overwatering is also important, as it can encourage the development of fungi.

• Biological Control: Encouraging biodiversity in the garden by attracting beneficial insects, such as parasitic wasps and insectivorous birds, can help naturally control pests.

• Constant Monitoring: Regularly inspecting trees for signs of pests or diseases allows for early intervention, which is often key to successful control.

By taking care of our trees, we not only protect the environment, but we also guarantee a natural legacy for future generations.