Malus domestica 'Fuji'
After removing the 'Cecile Brunner' rose that was growing over it, the Fuji apple tree is finally finding its corner a favorable place. It has set many fruits. This is a reliable indicator that the growing condition is good. However, five to six fruits per cluster are not all that good. It is more than one stem can successfully carry all the way to maturity. Fruit thinning needs to be done...soon.
Fruit Thinning is the removal of excess fruit to ensure the development of quality fruits and to enhance repeat blooming. First of all, reduced number of fruits will result in less competition for the photosynthates and thus bigger fruits. This also allows the plant to allocate more food for the overall development of the plant. Lesser weight from several fruits will also lessen the load of a single branch and thus avoid unnecessary damage to the spur.
Young apples infested with codling moth (Cydia pomonella )
Fruits that are touching each other encourage the spread of codling moth infestation into more fruits. As seen in the above picture, I lifted the other fruit away from the other one to expose the damage that has already been done on two fruits. If these fruits are allowed to stay the larvae inside the fruit will continue to make its tunnel all the way to the other fruits.
Fruit thinning is such an important process in commercial production to regulate the quality of the fruits. In large scale apple production, fruit thinning is often done with the use of chemicals such as the insecticide carbaryl combined with the growth regulator NAA (Naphthalene acetic acid) applied at petal fall.
For backyard gardeners like me, thinning is done by hand. Fruits are removed individually making sure to leave the best fruit in the cluster. Careful handling will also ensure that the chosen fruit and the fruiting spur are not damaged.
So with regrets I will abort some of my apple fruits.