Apples rot on trees for the same reasons why fruits, vegetables and food rot in general: allergens, temperature, light and water oxidation. Allergens are present in the atmosphere, such as plant pathogens, bacteria and fungi. Temperature changes can also cause rot and spoilage, as this increases and decreases the activity of enzymes in the apple. Light also affects the apple and can cause browning due to oxidation. Finally, the presence of water can cause the apple to rot in anaerobic conditions.
Therefore, when apples are stored on a tree, the conditions are more conducive towards rot and spoilage. During these months the apple needs to be kept in a cool, ventilated and dry place, while all sources of light should be avoided. This is because, the temperature is too high, it can speed up the ripening process leading to spoilage of the apple, and light can increase the enzymatic activity leading to browning of the apple, and water can increase bacterial growth and due to the lack of oxygen, can lead to the apple rotting.
Additionally, apples are highly susceptible to rot due to the fact that they are already ripe, and rot-causing bacteria, fungi, and other allergens can quickly bring the apple down. This is why it is highly recommended to not store the apples for too long on-tree, for the longer they stay on the tree, the quicker it spoils. Rotting and spoilage will likely occurs eventually and often quite quickly.
In conclusion, apples are highly susceptible to rot when stored on the tree due to allergens, temperature, light and water. Temperature and light can cause browning and can increase the speed of ripening leading to spoilage. The presence of water can lead to bacterial growth, and due to the lack of air can cause the apple to rot. Therefore, it is highly recommended to not store the apples on the tree for too long.
Types of rot
When apples are stored on-tree, three main types of rot can occur, namely, physical damage rot, bacterial rot and fungal rot, with bacterial rot being the most common. Bacterial rot occurs when the apples come into contact with organisms such as Pseudomonas, Serratia, and Erwinia carotovora, to name a few. These are present in the soil or water, and when the apples come into contact with these organisms, rotting occurs. In severe cases, breitling or browning of the apple will also occur.
Fungal rot on the other hand will occur when the apples come into contact with molds and mildews. These are often caused by Alternaria, Botrytis, Mucor and Rhizopus species. These organisms can cause deep rot to occur in the flesh of the apple, which will cause it to become soft and inedible. Lastly, physical damage rot is caused when the apples are damaged either during harvesting or handling. This type of rot will cause localized rot, as only the damaged area of the apple will be affected.
In order to prevent the different types of rot from occurring, it is important to store the apples in a cool and dry place, away from direct sunlight and sources of humidity. This can greatly reduce the risk of rot and spoilage occurring on the tree. It is also important to regularly inspect the apples for signs of rot and discard any that may be visibly rotten.
Harvesting & Storing
Apples should be harvested when they are ripe and ready to eat. This is because the longer the apples stay on the tree, the quicker they will rot and spoil. If the apples are left on the tree too long, they will become soft and inedible. Therefore, it is important to harvest the apples when they are ripe in order to preserve their quality.
Once the apples are harvested, it is important to store them in a cool and dry place away from light and sources of humidity. This will reduce the risk of rot and spoilage occurring. Additionally, the apples should be regularly inspected for signs of rot and any that appear to be rotten should be discarded immediately. This will reduce the risk of the rot spreading to other apples in the batch.
It is also important to note that apples should never be stored with fruits such as bananas and tomatoes, as these fruits produce large amounts of ethylene, which is a gas that accelerates the maturity and ripening of apples. Therefore, apples should always be stored separately in order to prevent the ripening process from happening too quickly.
Preventions
There are also various preventative measures that one can take in order to reduce the risk of apples rotting on the tree. Firstly, it is important to trim trees and remove any dead branches or diseased leaves, as these can harbour a range of pathogens and allergens that can lead to the apples rotting. Secondly, it is important to keep weeds and overgrown grass around the tree cleared, as this can contain pests and other organisms that can cause rot.
The tree should also be checked and sprayed for pests and diseases at least once a month, and any signs of disease or rot should be addressed immediately. Additionally, it is also important to avoid over-watering the apples, as this can lead to them becoming too moist, which can increase the risk of rot and spoilage. Lastly, it is important to harvest the apples when they are ripe, as this will reduce the risk of them getting over-ripe and spoiling.
Health risks
The presence of rotting apples on a tree can also lead to a range of health risks. This is because they can harbour a range of allergens and toxins, which can be hazardous to human health. Therefore, if anyone comes into contact with these rotten apples, it is important to thoroughly wash their hands with an anti-bacterial soap in order to reduce the risk of infection.
The presence of rotting apples can also attract pests, such as flies and wasps, which can bite and sting humans, as well as other animals. Therefore, it is important to regularly inspect the trees for signs of rot and dispose of any rotten apples as soon as they are spotted, in order to reduce the risk of pests and other organisms that can be hazardous to human health.
Uses of rotten apples
Although rotten apples are generally not suitable for consumption, they can still be used for a number of different things. For example, apples that have been left on the tree for too long and have become overly ripe, can be made into cider. This is because the overripe apples will produce a sweeter taste in the final product. In addition, rotten apples can also be made into applesauce, jam, jelly and other preserves.
Rotten apples can also be made into compost and mulch, which can be used in gardens and allotments in order to improve the soil quality. Finally, rotten apples can also be used for a range of medicinal purposes, such as for the treatment of sore throats, colds and flu. Therefore, although rotten apples cannot be consumed, they can still be used for a variety of different purposes.
