The main lemon diseases

The lemon tree is evergreen, has a pleasant appearance that gives it ornamental value and gives it a certain joy, in addition to producing healthy and always useful lemons. For it to grow healthy and lush, it is important to devote the necessary cultivation care, from fertilization to moderate pruning, among which the prevention and defense against animal diseases and parasites are also important.

Choice on how to define Phytosanitary defense in citrus plantations they are among those who most determine the environmental impact and healthiness of harvested lemons. In this regard, it is possible and advisable to treat lemon with biological methods, that is, with techniques that consist of working on prevention and using only certain products of natural origin for healing. , instead of poisoning the citrus fruits and the soil with synthetic pesticides.

Let’s see in particular, what are the most common diseases that affect the lemon tree , and how to solve any problem with ecological means. The speech instead of pests is discussed in the article devoted to lemon pests.


Sweater necklace, rubber bands and socks

The pathology of neck rot is determined by fungi of the genus Phytophthora , which cause wet spots to form on the bark at the base of the trunk. From the place that cracks, gummy exudates come out, which can also affect the roots. The foliage, and therefore the leaves, begin to turn yellow and deteriorate, the flowers are few and the ripe fruits remain small. In severe cases, the gummy spasm lesion affects the entire circumference of the trunk, leading to the death of the plant. Fruits affected by the disease become soft, covered with brown mold and give off a bad smell.

As a preventive measure against this disease it is useful to spread log dough on the stems of plants during the winter. In fact, log pulp is a natural preparation with a disinfectant action, widely used in biodynamic agriculture and obtained by mixing fresh manure, bentonite and often another ingredient such as horsetail infusion.

In case of persistent infestation, the trunk can be brushed with a copper product diluted in water , especially during periods of rain favorable to the disease, and possibly also spray the foliage. Affected fruits that have fallen to the ground should be removed to eliminate pathogen inoculation sites.

dry bad

The mushroom Phoma tracheiphila it causes discoloration and yellowing of the leaves of the branches of the upper part of the plant, which gradually dry out. But the infection can also start from the roots, leading to the rapid death of the plant, whose wood has a salmon-pink colour.

When recognizing the first symptoms on the leaves and twigs, these parts should be removed and burned. , cutting a little below the visible symptoms, then the cutting tools should be well disinfected. When a plant dies from this disease, it must be flattened, then it is important to disinfect the hole with lime and sulfur.

To prevent the disease, it is useful to treat plants with propolis extracts especially in the case of pruning or hail wounds, which are possible entry points for the pathogen. Once again, the log dough has a preventive disinfectant effect .

For treatments with continuous infection, in addition to the removal of parts visibly affected by the pathogen, it is possible to use copper always in the doses and modes of use recommended on the label of the product purchased.


On the twigs affected by the bacteria Pseudomonas syringae depressed reddish-brown spots can be seen, from which droplets of gum can escape . The infection, if it reaches the leaves, causes them to wrinkle but not fall off, while on the fruits one can notice round spots of about 1-1.5 cm, with bacterial exudates, which may not even appear only after harvest.

This pathology can also be contained by copper treatments but it is useful to prevent it by spraying propolis especially in the event of damage to the plant caused by wind, hail or pruning.


Even if he soot should not be considered a disease in the strict sense since the fungus does not directly infect the leaves but adheres to the honeydew of aphids and other insects, the consequence is that the leaves reduce their photosynthesis when thus covered by the typical dark, smog-like dust.

Therefore, defense must take place in insects that stain the plant with honeydew. thus a treatment with Marseille soap against aphids could also eliminate traces of soot.

sorry for the virus

The Tristeza virus is considered the most dangerous of those affecting citrus, as it has caused the death of millions of plants around the world. Plants grafted onto bitter orange, grapefruit or lime are particularly sensitive to it.

The infected plant initially slows down in growth, the leaves turn yellow from the veins and fall off. The plant tries to respond by producing new shoots, but they remain small and light green. If the virus starts in the roots, it attacks the stem and the water absorption capacity of the plant is reduced. In some cases, the plant initially produces more lemons, which remain small, but this also depends on the different strains of the virus, which leads to certain differences in the symptoms of the plant.

There is no direct remedy against this virus, but we know that the vectors of this virus are aphids and therefore we must fight against them, as with soot. Irretrievably dead plants must be eradicated and burned, and the tools used disinfected.

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