What are these diseases?
Today we will talk about pome fruits.
Pathogens are numerous, most often they are fungi, sometimes bacteria.
For apples pears, quinces and nashi we often meet:
One of the best known is due to cryptogams of the lenticellar rot group at ‘Gloeosporium‘ which begins with a brown circular spot from which emerge concentric fruiting bodies at the beginning a bit like moniliosis.
· Moniliosis: Is characterized by concentric circles of fruiting bodies on the rotten brown part.
Quince trees are very susceptible to this disease.
Botrytis or gray rot which often develops a gray down on the surface of the affected fruits
· The Penicillium due to fungus well known thanks to Alexander Flemming discoverer of penicillin, the first antibiotic.
· The disease of the fly which develops around the “fly”, remnant of the flower. Due to fungus Nectria galligena responsible for nectria cankers.
· Pseudomonas syringae, agent of bacterial dieback of many trees, Produces brown necrosis on pears.
· Scab, by a late attack which evolves very slowly and which results from autumnal contaminations on the tree. Recognized by small dark dots in the center of small brown spots indented on the skin of the fruit.
How are these fruits contaminated?
In general, we pick and bring in fruits that seem healthy, but they are often already contaminated by fungus spores or by bacteria present in the twigs.
But they can also be contaminated by equipment and storage rooms:
• Fruit tree
• Shelves and racks
• Containers, crates, baskets.
In the orchard:
Throughout the season, fungal spores fly and land on twigs, flowers, stems, and even tree roots.
But there are also all the pathogens that have been installed for more or less long time in the trees, especially in the branches where contamination often occurs at the time of harvest and leaf fall. They leave a small scar when falling in the fall which will take at least a week to close, but during this time the scars are entry points for pores and bacteria.
What other pests are found on or in fruit that can cause storage problems?
Insects, mainly codling moths plus a few other fruit-specific flies. Through their parasitism, they create wounds which are entry points for storage diseases. It can also be for example slugs on fallen fruit.
The fight against these diseases is preventive
Of course, prophylaxis is the only control method available to amateur gardeners.
It is necessary to ensure as much as possible that the fruits are healthy before storing them.
But sometimes the picker and the manipulations make small wounds on the fruits which are so many doors for the entry of pathogens.
Be careful when picking nails that are too long (put on household gloves).
In addition, we must not forget to protect the fruit trees from these diseases which contaminate them when the leaves fall. For the moment, the most suitable means is one or two copper treatments (Bordeaux mixture) at the beginning and at the end of leaf fall. A third treatment may be necessary in the event of a long humid and warm period.
But the main act(ion of prevention is not to leave diseased fruits on the branches (mummies) or on the ground and to evacuate all the leaves from under the trees.
Conversely, when the trees are healthy and the summer has been dry, treatment is not necessary.
But it is also necessary to store the fruits in clean, disinfected equipment and in a clean and ventilated room.
A weekly visit makes it possible to evacuate as quickly as possible the fruits which are beginning to deteriorate.
Attention :
It is important not to wash the fruits before bringing them in because this will increase the presence of water and the development of diseases. Likewise, it is necessary to harvest the most dried fruits possible. Avoid harvesting early in the morning during dew.
Ask all your questions during the gardening program on Sunday morning on France bleu Isère from 9 a.m. to 10 a.m. by calling 04 76 46 45 45