The Mal Secco: how to combat this pathogenic fungus

Caused by the fungus Phoma tracheiphila, this pathogen can cause extensive damage to crops, impairing production and fruit quality. In this article we will take a closer look at the characteristics of Mal Secco, its symptoms and the most effective prevention and control strategies.

What is the Mal Secco?

The Mal Secco is a vascular disease, the fungus penetrates the lymph vessels of trees, obstructing them and preventing the proper transport of lymph. This leads to the progressive drying out of leaves, branches and, in serious cases, the entire plant. Let us see in detail how to recognise the first signs of the fungus on the plant.

How to recognize the Mal Secco: the main symptoms on the plant

The symptoms of Mal Secco may vary depending on the stage of development of the disease and the variety of citrus fruit affected. However, some characteristic signs are common to all infected plants:

- Yellowing of the leaves: starts at the veins and extends to the entire leaf blade.

- Desiccation of shoots and apical twigs: affected branches have a dry and leathery appearance.

- Leaf fall: the affected leaves fall early, leaving the branches bare.

- Abnormal colouring of the wood: if you cut into the bark of an infected branch, you will notice a characteristic reddish or salmon colouring of the wood.

- Presence of pycnidia: tiny fruiting bodies of the fungus, visible to the naked eye as black dots on the surface of dry branches.



As mentioned, dry rot develops in several stages:

1. Initial phase: the first symptoms appear on the apical leaves, with yellowing and desiccation.

2. Acute phase: the disease progresses rapidly, involving an increasing number of branches and leaves.

3. Chronic phase: the plant enters a phase of progressive decline, with general decay and reduced production.

How to recognize the Mal Secco: the main symptoms on the plant

Prevention of mal desiccation is essential to safeguard citrus fruit crops. Here are some steps you can take to prevent the spread of this terrible disease.

1. Check the plants periodically

It may seem trite to say, but the first measure to counteract the onset of the fungus is to check the citrus plants periodically, especially during the winter months. During the winter, in fact, the risk of infection is much higher due to the colder weather conditions. The first symptoms of infection appear in late winter and progress into spring.

2. Cover plants with during the winter months

Frost, hail and wind often cause wounds on the various plant organs, increasing the risk of infection. For this reason, we recommend protecting citrus plants with nets. In addition to protecting the trees from injury, they also protect them from the cold.

3. Preventive treatments with cupric products during the winter months

Cupric treatments, which are particularly suitable in nurseries, exert an effective preventive effect against fungal diseases, especially if applied during the cold months and after adverse weather events such as hailstorms, strong winds or frost. Such protection, of the superficial type, is recommended to reduce the risk of infection, but cannot eliminate infections that are already underway.

4. Avoid deep soil cultivation in the autumn period

Ploughing and tilling during rainy periods and the use of herbicides without working the soil make citrus plants more susceptible to root diseases. Wounds caused by tillage and the superficial position of the roots after weeding facilitate the entry of pathogenic fungus and bacteria.

To combat weeds, we recommend working the soil with mechanical weeders. Mechanical weeding improves soil porosity and fertility and contributes to optimal plant development. For more on this topic, read our article on mechanical weed control.

5. Maintain the right plant spacing

The right plant hydration and ventilation also contribute to limiting the spread of the fungus. A well-ventilated foliage facilitates the action of plant protection products. Therefore, we recommend keeping the plants well aerated, avoiding excessive plant density.

6. Carry out regular and precise pruning with professional, disinfected tools

Let us begin by saying that pruning plays a crucial role in the prevention and control of all diseases, especially dry mal. Balanced and above all regular pruning makes the plant more vigorous and resistant to disease.

It is equally important to pay attention to the cleaning and disinfection of pruning tools. It is, in fact, very important to clean pruning tools after use, as they are one of the main ways in which harmful bacteria and fungi move from one plant to another.

If the plant already has obvious symptoms, it is best to proceed with remedial pruning, removing the compromised parts. It is preferable to make a clean, precise cut about 30 centimeters from the dry part affected by the fungus. We recommend disposing of the infected branches immediately by burning them on site. By removing dry and diseased branches, the spread of the fungus is limited.

The use of high quality pruning tools, such as those produced by Zanon, play a fundamental role in the prevention of dry rot.

Professional pruning shears and plug-in battery powered pruners, made of resistant materials and sharp blades, guarantee clean and precise cuts, reducing trauma to the plant and promoting rapid wound healing.

In addition, the lightness and ergonomics of our tools facilitate the farmer's work, reducing the risk of errors and injury to the bark of the tree.

Mal Secco poses a serious threat to citrus crops. However, by adopting the right prevention and control strategies, it is possible to limit the spread of this pathogenic fungus and safeguard citrus production.
Investing in quality pruning equipment and following expert advice are essential steps to guarantee the health and productivity of your citrus groves.

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