American Tree Experts

6 Most Common Plant Diseases and Their Treatment (Part 1) 

Learn about the symptoms, causes, and treatments for some of the most common plant diseases.

Like all living beings, plants are susceptible to catching diseases. 85% of plant diseases are caused by fungal organisms. However, viruses and bacteria also attack plants and can compromise the health of the plant. A visible sign of a diseased plant is the presence of pathogens like fungus or nematodes on the plants.

The disease affects the health of the plant and results in low yield and eventual death of the plant. In this article, let us explore the common plant diseases and their treatment.

Apple Scab

Apple scab is a fungal disease that is common in apples and ornamental crabapples. Also known as Venturia inaequalis, this disease attacks the leaves and fruits. Common symptoms include:

  • The development of pale yellow spots on the leaf’s upper side
  • Development of dark velvety spots on the lower side of the leaf.
  • Deformation and early dropping of infected leaves.
  • Infected fruits develop scabby spots which are indented inside the fruit and may have velvety spores in the middle.
  • Infected fruits become deformed and cracks appear in the fruits, which allows the entry of secondary organisms into the fruit.

The following conditions are most suitable for the development of Apple scab:

  • Cool and wet weather of spring and early summer.
  • The fungal spores are carried by wind or rain.
  • The disease is most prevalent during temperatures of 55 – 75 degrees Fahrenheit.


common plant diseasesAnthracnose is another fungal disease that is caused by a fungus that belongs to the Colletotrichum genus. This disease is most prevalent in the eastern part of the United States. Anthracnose is a common plant disease that affects many species. The severity of the disease is so quick that it can turn a strong plant into organic waste within a few days. Symptoms of anthracnose disease include:

  • Development of dark, water-soaked lesions on stem, fruit, or leaves.
  • Presence of pink, gel-like spores in the center of the fruit.

This disease spreads during the winter season. Optimal conditions for its spread and development are:

  • Cool wet weather. The fungus germinates in the presence of moisture.
  • Spores grow at a temperature of 75-85 degrees Fahrenheit.

The spores are spread through wind, rain, insects, and garden tools.

Bacterial Canker

As the name indicates, it is a bacterial disease caused by the bacterium Pseudomonas syringae. This bacterium enters the tree through a compromised or injured bark. Injury may have occurred due to frost damage, or during the pruning process.  Bacterial canker commonly affects cherries and plums but can also cause disease in apricots, peaches, and other types of stone fruits. The common symptoms of the development of bacterial canker are:

  • The appearance of the sunken, or gummy lesions on the trunk or twigs of the plant.
  • Oozing of sour-smelling sap from the punctured areas of an infected tree during the spring season.
  • The infected parts of the bark became darker with the appearance of a reddish-brown tinge. Those parts are moist when touched.

The bacterial canker infection is spread during the fall, winter, and spring seasons when the weather is cool and wet. Rain, water and pruning tools are the carriers of the bacterium.

If you fear that your trees and plants are suffering from plant diseases, then waste no time and contact American Tree Experts. We provide effective and proactive Disease Management for plants are trees. Call us at 973-744-6091 to get a free estimate of our services. We operate in Mont Clair, New Jersey, and nearby areas.

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