What is Anthracnose?
It is important to note that anthracnose is a term that collectively refers to various diseases that attack the different parts of a plant. The fungus that causes the disease will depend on the specific plant where it thrives. For instance, in bananas, the cause is Colletotrichum musae. On the other hand, the cause of the disease in mangoes is Colletotrichum gloeosporioides. Meanwhile, for oak, the cause is discula quercina.
The fungi that bring anthracnose in different plants will overwinter in plant debris with infection. The lifecycle of the disease will start in spring as the temperature is favorable for the spores. Aside from spring rain, the pathogens also favor environments where the temperature ranges from 50 to 68 degrees Fahrenheit. They will spread to other plants through water and wind. Once the spores land in a new plant, it will take up to a few days or weeks before the first signs of infection will be apparent.
Identifying Anthracnose’s Damage
Since anthracnose is a collective term for various diseases affecting several plants, the hosts are diverse. Among others, some of the most common hosts include mango, banana, passion fruit, rockmelon, honeydew, avocado, capsicum, pepper, tomato, oak, maple, elm, and buckeye.
The symptoms of anthracnose will vary depending on the host and the part of the plant that the fungus attacks. Generally speaking, below are some of the signs that you should watch out for:
- Discoloration of leaves is one of the early signs of the disease. Older leaves are more resistant to the pathogen. The leaves may turn brown or tan. They will grow irregular spots or blotches. Distortion and curling of the leaves are also common. At its worst, the host will suffer from defoliation.
- In fruits, there will be brown and circular spots, which will start out small. As it ages, the spots will be darker and the sunken spots will enlarge. The appearance of pinkish spores will also be apparent. Through time, the fruits will rot. This will also make it susceptible to the entry of other pathogens that can cause more problems.
- Twigs will have cankers and swollen edges. The bark of the tree can suffer from girdling. The latter will destroy the tissues that absorb water and nutrients, and hence, inhibit the growth of the tree. Orange-brown blisters may also appear on the twigs, especially the young ones.
Results of Infestation
Most of the damages from anthracnose will be cosmetic in nature. They will affect the physical appearance of the different parts of its host, especially the fruits and leaves. They will initially be small and as they become worse, they will be larger and darker. Defoliation can also occur. If the disease attacks the fruit, it will turn unattractive and hence, it will be unmarketable. This equates to profit loss on the part of the growers.
How to Get Rid of Anthracnose
Natural and Organic Solutions
Below are some of the most effective ways to prevent anthracnose without resorting to the use of toxic chemicals:
- It all starts with the proper selection of the seeds and plants to grow. Purchase your seeds only from a reputable nursery and see to it that it is disease-free. An infection in the seed means that the plant, when it grows, will suffer from anthracnose. Also, look for varieties that are resistant to the fungus that carries the disease. For trees, some of the resistant varieties include white red oak, blue ash, and Japanese walnut. Charleston gray watermelon and Calypso cucumber are also highly-resistant.
- Garden sanitation is also essential for the prevention of the disease. Keep the soil free from plant debris, such as fallen fruits and rot. The latter can be overwintering sites for the fungi.
- Right watering practices will also be a critical preventive measure. Avoid using an overhead sprinkler. A drip sprinkler is the better option. Also, avoid touching the plants when they are wet as this can increase its susceptibility to infection. Too much water is bad for the host plants as this can attract the pathogens. Read this article to find the best sprinkler for your lawn.
- In the case of trees, regular pruning is also necessary. This will take out the part that has an infection, making it less likely to spread to the healthy parts of the tree. It also improves air circulation and light penetration, making the tree less susceptible to the pathogen.
- Crop rotation every two to three years is another effective solution. Alternate with crops or varieties that can resist the disease. Be sure to clean the garden and rake the soil to remove the fungus.
- Rather than using pesticides or chemicals in your plants, try baking soda spray as a natural alternative. Combine one tablespoon of baking soda, one tablespoon of vegetable oil, one tablespoon of dish-washing liquid, and four liters of water. Stir well and use it as a spray on your plants. This will provide protection from the pathogen that can cause anthracnose and other common plant diseases.
Especially for commercial growers, it is common to use chemicals to prevent anthracnose. Fungicide application is common, although it is important to note that it is a preventive and not a curative measure. Fungicides will offer protection only on the healthy tissues of the plant and will not help in eradicating an infection that is already evident.
Some of the most common active ingredients in fungicides that prevent anthracnose include chlorothalonil, propiconazole, mancozeb, and thiophanate-methyl. On the other hand, to be specific, some of the most common brands include Banner Maxx, Cleary’s 3336, Dithane, and Ortho Max Garden Disease Control.