Disease name: gray mold
The scientific name:Botrytis
Type of disease: fungal
Disease family: cinerea Botrytis
(Stages of lemon fruits being infected with gray mold)
- The causes of disease:
The fungus is transmitted through the soil, where it moves to infect all parts of the plant, and the lower leaves are considered the most susceptible to infection, especially leaves injured mechanically or through cold and frost.
- Symptoms of the disease:
It begins to appear in the form of water-soaked spots on the leaves. They are initially white and then gradually change to grey, until they cover most of the leaf and cause it to wilt. The fungus attacks the flowers and small fruits of lemon and is characterized by its gray to greenish-gray spores. The fungus can develop in the flowers. Or on young branches, gray rot reduces fruit set and damages young fruits, leading to the formation of raised areas or ridges on the peel.
(Comparison between Penicillium fungus and gray mold fungus on lemon fruits)
- Conditions suitable for the spread of the disease:
Infected petals are the main source of infection for fruits and branches, as the fungus lives in conditions of humidity and cold for long periods. (15-20) degrees Celsius is considered the optimal temperature for mushroom growth. Excessive irrigation and shade also increase the level of the disease.
- Disease development cycle:
In the presence of suitable weather conditions, the fungus develops, as the spores spread, forming a gray layer on the fruits, stems, or leaves. It can develop to reach the roots, and the fungus also lives on decomposing organic materials.
- Losses from the spread of disease:
Symptoms of the disease sometimes appear during storage, which increases losses, and in some sensitive varieties, it may cause complete crop failure.
- Control:
The use of biocides is very effective in combating the fungus, and in the case of early infection, chlorothalonil can be used sparingly through foliar spraying to avoid resistance to the fungus.
- Preventive measures:
- Use resistant and tolerant varieties.
- Maintain an appropriate distance between trees to avoid transmission of infection.
- Fertilizing and using mulch in an appropriate manner.
- Avoid excessive watering.
- Applying copper fungicides before rain is expected reduces the incidence of gray mold.
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