It can happen that zucchini rot directly from the fruit, especially from the flower that is at the top of the zucchini.
If the problem affects the fruit directly and only from the apical flower, it is most likely a bacterial disease, especially Erwinia Carotovora. This disease of garden plants mainly affects zucchini, but can also attack other vegetables (such as fennel, potatoes, peppers and, as the name of the problem suggests, carrots).
It is precisely a bacterium that proliferates in situations of high humidity and also takes advantage of wounds to attack plants. Among the diseases of zucchini, it is one of the most widespread and soft rot, if not controlled, spreads from the fruit to the plant. also for this reason it is better to learn to recognize, fight and above all prevent this rot.
Erwinia carotovora: characteristics
Bacterial disease due to Erwinia carotovora is not easy to identify until the fruit rots to an irreversible stage. Normally, the rot is soft and moist. The bacterium is naturally present in soil and when it finds the right conditions, it checks for pathology.
This disease proliferates when temperatures are between 25 and 30 degrees Celsius in humid conditions. In the zucchini plant, it frequently takes advantage of the rotting flower, which is collected damp inside, to attack the fruit. The bacterium can also attack other parts of the plant, especially in the event of wounds caused by insects or atmospheric agents.
Zucchini mild rot can spread from the fruit and wilt the entire cucurbit plant to death.
How to fight Erwinia Carotovora
This bacteriosis of the zucchini plant cannot be effectively cured by biological methods, but it is possible to prevent it and, in the event of adversity, to thwart it by limiting the damage.
Prevention of soft rot
Prevention is, first, avoiding conditions that favor the spread of the bacteria, so that there is persistence of the bacteria and unhealthy humidity, including stagnant water.
- Work the land. Proper soil preparation, which promotes drainage, is most important in preventing rot.
- Fertilization . An excess of nitrogen can promote the development of Erwinia Carotovora, reducing the immune defenses of the courgette plant.
- Irrigation. Be careful not to overwater, as overwatering can cause standing water.
- Installation distance. Keeping zucchini plants the right distance apart also helps with air circulation and limits problems.
- Crop rotation . Avoiding planting zucchini in soil where a rot problem has already occurred is an important precaution.
- Mulching and fruit growing . If the fruit is not in direct contact with the ground, it will be more difficult for it to be attacked by the bacterium Erwinia Carotovora. Mulch is very useful for this purpose.
- Variety. Choosing zucchini varieties that are tolerant and less prone to rot is another way to avoid problems.
Control of Erwinia carotóvora with biological methods
If you find infections among our zucchini crops, you must quickly remove the diseased fruits and remove them from the garden to prevent the spread of infection. Plant material from affected plants should be discarded or burned, not used in composting, so as not to risk transmitting the disease back to the garden.
This bacteriosis is combated with copper, in particular with treatments with Bordeaux mixture, a treatment authorized in organic farming, capable of containing the disease by preventing its transmission from plant to plant.