Blight on lemon plant

Disease name: Blight on lemon plant

The scientific name: Pseudomonas syringae

The type of disease: Bacterial

Disease family: Pseudomonas

(Lemon leaves wilting as a result of blight)

• The causes of disease:

Lemon plants suffer from blight due to the presence of bacteria Pseudomonas syringaeThese bacteria live on the surface of the leaves and become pathogenic in long-term, humid weather conditions. The damage is more severe on the side exposed to winter winds.

• Symptoms of the disease:

Symptoms of infection appear in the form of black spots in the leaf petals and advance to the neck of the leaf, leading to the leaves withering and wrinkling, but they remain attached to the branches and fall in the case of severe infection. Entire branches may also die, and the infection can lead to the appearance of small black spots on the fruit.

• Disease development cycle:

These bacteria enter the plant through leaf pores, and wounds on the branches caused by thorn punctures, strong winds, or insect injuries can help spread the bacteria within the plant.

• Conditions suitable for the spread of the disease:

Wet, cold, and windy conditions during winter and spring greatly favor the development and spread of blight bacteria. Pseudomonas syringae In the ice, which means that it lives under harsh weather conditions and temperatures below zero degrees Celsius.

(lemon fruits infected with blight)

• Losses resulting from the spread of the disease:

Blight bacteria attack the immature leaves of lemon plants, which affects the health of the plant in general. As the infection intensifies and the plant continues to be exposed to frost and rain, the size and quality of the fruits decrease, and the plant may die in some cases.

• Control:

1. Adding iron chloride compounds to hydroxide granules at the beginning of winter and before the field is exposed to frost.
2. Apply copper compounds to the plant correctly.
3. Planting windbreaks.

• preventive measures:

1. Use dense varieties with relatively few thorns to prevent wind injury.
2. Pruning dead or diseased branches in the spring after the rainy period to limit the spread of the disease.
3. Good fertilization of the plant helps in resisting bacteria.
4. Sterilize agricultural tools before use.

• Sources:
• https://ipm.ucanr.edu/agriculture/citrus/bacterial-blast-citrus-blast/
• https://plantix.net/ar/library/plant-diseases/300038/blast-of-citrus/