Cladosporium spp.

Cladosporium rots

General

• The Cladosporium spp. are among the most common fungi in the world. More than 40 species are known.
• A few species are reported on eggplant, in particular Cladosporium cladosporioides , a very common species in many ecological niches, and responsible for rots on ripe fruits and during storage, as well as leaf spots, for example in Pakistan. But also Cladosporium oxysporum reported in China as responsible for leaf spots on eggplants grown in greenhouses. Surprisingly, C. cucumerinum would attack eggplant, in addition to Cucurbitaceae, also causing leaf lesions.
• In France, rare damage to eggplant fruits can be observed at harvest or during storage.
• Organs attacked  : mainly fruits.
• Symptoms : rots on eggplant fruit, the affected tissues take on a dark tint, more or less collapses and becomes covered with a dark green to blackish mold.
• Possible confusion  :
• Signs : rotten tissues are gradually covered with spore pads or even large velvety colonies whose color fluctuates over time. At first greenish, they take on an increasingly dark green color, eventually reaching black.

Biology  

The Cladosporium spp. often live as saprophytes on eggplant and in its environment, becoming opportunistic pathogens when the physiological state of the fruits is modified (presence of wounds, advanced maturity, etc.).

• Conservation : considered to be the most common molds in the world; they are found in the soil, as well as on the most diverse hosts and substrates.
• Infection : penetrate the fruits of eggplant mainly when ripe, can be directly through the cuticle, most certainly through microcracks, various injuries such as damage linked to pathogenic insects or fungi, physiological micro-bursts , bird pecks or sun burns. Subsequently, the mycelium grows very extensively, growing in all directions inside the flesh which gradually degrades.
• Sporulation : Cladosporium spp. sporulate quite easily and abundantly on the surface of the fruits, and their conidia are dispersed by wind, drafts and / or splashing water following rains and sprinkler irrigation.
• Dissemination : wind, but also rain, sprinkler irrigation ensures the dispersal of the spores. Seeds, workers, especially through their tools, also contribute.
• Conditions favoring its development : thrive at fairly wide temperature ranges, favored by humid conditions. Rather, they are pathogens of fruits harvested late and stored.

Protection

• This phytosanitary problem does not require the implementation of special protection methods.
• Choose a planting density ensuring good aeration of the vegetation, good wiping after rains or sprinkling irrigations.
• Avoid any stress to the plants, and ensure them a balanced manure, in particular in nitrogen.
• Mulch the soil to form a mechanical barrier reducing contamination
• Prefer drip irrigation rather than sprinkling.
• Improve the ventilation of the vegetation as much as possible in order to reduce its humidity.
• To control the development of other pests of eggplant, in particular those causing damage to fruits and thus promoting the parasitism of these opportunistic fungi.
• Harvest before the fruits have advanced maturity.
• Eliminate plant debris fairly quickly, especially rotten fruit during and at the end of cultivation. They will have to be destroyed or buried deep.