Very often, a apple, pear and plum tree, will lose many of its fruitlets - young fruits - in mid-summer for no apparent reason. Why is this?
The answer is quite simple and basic.
Firstly it is so common that it has a 'name'! June Drop.
Fruit 'naturally' sheds some of its burden in early summer - normally June. This is especially the case after a good show of flower in the spring, and a good pollination, resulting in many fruits setting.
The fruit tree decides that it cannot cope with the huge crop it now has to play mother to! The easy answer - in nature - is to get rid of the problem. The Apple tree - or Pear or Plum tree - simply drops the excess fruit in order that the remaining apples pears or plums can survive and develop into healthy fruits.
Some notoriously good croppers - such as the James Grieve Apple - carry out this 'cull' in early summer, but all trees will do it if there is a perceived threat to their future.
To survive, in real nature, the fruit tree needs healthy fruit. healthy fruit will then produce healthy seeds and therefore potentially healthy, strong offspring. Clever things aren't they!
This shedding of excess fruit actually starts immediately after flowering, but is not noticed normally until June, when the dropping fruits are seen as potential apples of pears going to waste. There is nothing that can be done to prevent it It is a fully natural event and part of the plants insistence on bearing good fruit.
The fruit drop actually takes part in two distinct stages. The first stage, is with the natural dropping or shedding those fruitlets that were not pollinated well, and would therefore never make it to the proper seed-bearing fruit stage. This first stage of fruit drop - for apples, plums and pears, takes place as soon as the flowers have faded. The dropped fruit are usually the size of a pea, and accepted as natural loss by gardeners.
The second Fruit Drop stage, which happens towards end of June - dependent upon seasonal fluctuations - is the one that causes consternation for gardeners, as they see potential 'fruit' dropping off the tree for some reason. I can pin this down quite accurately to the third week in June this last year (2013). My mail box will testify that is correct! This second 'real fruit' drop is where the tree is deciding upon how much fruit it can take forward in life. Fruit trees realise their limitation, and will 'adjust' the crop by discarding fruit that they are unable to support with the current nutrition situation!
The last half of the preceding sentence is important, for everything depends upon the trees' ability to crop a heavy load.
If you have regular and substantial June Fruit drop each year, then it is time for you to act in relation to providing nourishment to the tree by way of feeding your fruit trees. The odds are, that if you 'correct' any deficiency, then the June Drop will not be as traumatic - for you or the tree!
There is a tendency for trees to grow out of June Fruit Drop. Quite simply, the younger trees need to grow into large trees, and they will ensure that the available food resources will be allocated to growth rather than fruit production. Fruit drop normally abates - unless there are environmental causes in any given year. - as the trees get older, more established, and more concerned about their potential offspring (fruit) than they are with their own growth. They are good parents!
This may also interest you.