Penicillium  spp.

Rots Penicillium

(blue mold)

General

• More than 200 species of Penicillium are known.
• Very ubiquitous fungi found on the most diverse substrates (dry food products, spices, cereals, fresh fruits and vegetables), in the soil, on decaying plants and compost, on wood.
• Saprophytes, sometimes opportunistic parasites manifesting themselves for example on seeds, on ripe fruits and / or during their conservation.
• Very few species of Penicillium are reported on rotten fruits, mainly when ripe, in the fields and during storage.
• Their attacks on fruits are rather rare, taking place especially at the end of cultivation on ripe fruits and after harvest.
• Organs attacked  : mainly fruits.
• Symptoms :
  
  • Rots on eggplant fruits, the affected tissues take on a beige tint, more or less collapse and become covered with a blue mold.
• Possible confusion  :
• Signs : rotten tissues gradually become covered with spore-bearing pads, the color of which fluctuates over time. First whitish, they turn blue ( blue rot , blue mold), or even gradually green and darken.

Biology  

This s Penicillium spp . often live as a saprophyte on eggplant and in its environment, becoming an opportunistic pathogen when the physiological state of the fruits is modified (presence of wounds, advanced maturity, etc.).

• Conservation : present in many soils, on plants and on the most diverse plant debris in the form of mycelium and spores. Many of them are part of the eggplant phylloflora.
• Infection : penetrate the fruits mainly when ripe, this in several ways: 
  • Directly through the cuticle in the presence of exudates;
  • By contact of rotten fruit with healthy fruit;
  • Through the stomata, lenticels and microcracks, various injuries such as damage related to insects or pathogenic fungi, physiological micro-bursts, bird pecks or solar burns;
  • Secondarily to attacks from other pathogenic fungi.
    Subsequently, their mycelium grows very extensively, growing in all directions inside the flesh which gradually degrades.
• Once in place, they quickly invade the tissues.
• Sporulation spore : Produce on colonized tissues pads bearing innumerable conidiophores generating conidia numbering in the millions.
• 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 : favored by high humidity and rather high temperatures. Dews, low continuous precipitation (5 mm) or sprinkler irrigation are sufficient for their extension. Fruits that have lost their integrity (wounds, damage linked to a primary colonizer) and / or have reached a more or less advanced stage of maturity are particularly vulnerable.

Protection

• This phytosanitary problem does not require the implementation of special protection methods.
• Use healthy seeds. If in doubt, uncoated seeds can be treated with hot water, with a fungicide.
• Disinfect equipment used for training.
• Do not plant in hydromorphic soils.
• 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.
• Control the development of other pests of eggplant, in particular those causing damage to fruits and thus promoting parasitism of this opportunistic fungus.
• 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.