Apple tree loses apples prematurely: what to do?

June fruit fall

If the apple tree loses a lot of unripe fruit in June/July, it is usually the so-called June fruit drop. This is a natural process that is automatically initiated by apple trees when they are “overwhelmed”. They usually shed undersized, underdeveloped fruit to improve the supply of the remaining specimens. Various reasons are decisive for the initiation of this type of “selection”.

Missing signals

Signals are sent out that fruits take a penalty if they have the potential to grow delicious fruit. This takes place via growth regulators and various hormones. If this feedback is missing, an apple tree evaluates these fruits as superfluous ballast. As a result, the supply is reduced or the fruits are not “requested” so that their stems become corky and they no longer hold on the tree. The causes of this automated natural process are:

• Insufficient fertilization of the fruit
• hormone and growth disorders
• Disease of tree or fruit

Depleted apple tree

If apple trees brought a lush harvest in the previous year, the June fruit often drop in the following year. This is due to overstressing of the tree caused by the previous year’s high demands on nutrients and energy. In short: high crop yields are often followed by a relief in June/July, which apple trees take care of by shedding unripe specimens. In this case, experts speak of an alternation.

Uncertain fruit supply

If a malus is weakened or the soil does not provide enough nutrients, it “sorts out” fruits in order to be able to provide a smaller number of fruits better/sufficiently. This is particularly the case when the tree bears (too) much fruit. As a rule, he throws off the smaller, underdeveloped and/or diseased/affected fruits. In this way, apple trees reduce their nutrient and energy requirements in order to be able to carry at least the strongest specimens to maturity.

June fruit waste – what to do?

Home gardeners and home growers can’t argue with the natural process of June fruit dropping. However, some measures are useful:

• early hand picking of the smallest fruit can reduce the number of apples that fall prematurely
• Carry out manual selection by the beginning of June at the latest, before flower buds begin to form
• Cut trees regularly to promote strong, healthy growth and energy production
• pay attention to optimal location with correspondingly ideal soil quality

lack of water

If large, healthy-looking apples in particular fall off in midsummer, one of the most common causes is a lack of water. Normally, apple trees are excellent self-supporters, but during prolonged dry spells in midsummer, watering is required. If they suffer from a lack of water, the moisture content is reduced, stalks become more porous and no longer hold the fruit weight permanently. The result: depending on the severity of the water shortage, the apple tree loses fruit. The only thing that helps here is the daily watering of the malus, as soon as drought and high temperatures provoke a lack of water.

nutrient deficiency

If natural June fruit drop is not a cause of apple shedding, it could also be due to nutrient deficiencies related to soil quality. Especially with older apple trees that have been in the same location for many years or with specimens that were planted in the same place where another fruit tree had previously stood for years, the nutrient content in the soil is usually no longer sufficient. Predominantly a malus responds to this with June fruit drop, but the lower the nutrient level, the higher the risk of underdeveloped apples that can drop throughout the season. Therefore:

• Provide soil with suitable nutrient fertilizer at least once a year
• Best time to fertilize: April
• Additional fertilizing for exhausted soil and old apple trees: in May/June

signs of aging

As an apple tree grows older, the risk of defoliation increases. That means: the old malus forms fewer and fewer shoots, leaves and fruit. Due to age, the tree becomes increasingly weak, which means that existing apples find less and less support the bigger/thicker they get. With a strong annual blend, the natural aging process can be slowed down and there is a high chance that the fruit will have sufficient support. The following should be considered when cutting:

• cut early in February/March on a frost-free day
• Shorten shoots that grow inwards and cross each other as well as shoots that bend downwards (trimming out)
• Cut branches of the same rank at the same level to achieve ideal “juice balance”.
• Do not cut fresh/new shoots as buds form on them

pest infestation

If an apple tree loses its harvest fruit prematurely, a possible pest infestation is the easiest of all possible causes to recognize, since there are clear traces on the fallen fruit. One of the most common pests that result in early fruit drop is the

codling moth

• Maggots are found in bark, buds and young fruits
• affected apples all fall off
• red bordered eating and drilling holes in the apple
• visible larval droppings
• Flesh clearly discolored

What to do?

• from June wrap the tree trunk in several layers of corrugated cardboard (here the larvae remain until pupation)
• read off pests on corrugated cardboard after pupation
• September remove corrugated cardboard
• remove loose pieces of bark
• Spray off the trunk bark with high water pressure (to remove any egg deposits)
• Check for typical signs of infestation at short intervals
• Dispose of infested apples immediately in the household waste (not on compost!)

diseases

If the malus loses its fruits, various diseases can be to blame. Fungal pathogens cause the most common  apple tree diseases. When planting new plants, you should therefore always use resistant varieties.

Apfelschorf (Venturia inaequalis)

Apple scab can cause increased waste of unripe apples. This is a sac fungus that begins to spread mainly in the spring. At temperatures between ten and 20 degrees Celsius in combination with high humidity, the apple scab finds optimal conditions. This fungal disease can be recognized by the following signs in addition to excessive fruit drop:

• brown spots on upper leaf surfaces
• brown spots and star-like crack shapes on fruits
• Apples spoil on the branch
• increased leaf drop

What to do?

So far, there is no promising method of combating apple scab. The infestation can only be contained by separating and safely disposing of all infested plant parts and apples. Regular thinning of the apple tree allows moisture to dry/evaporate better and reduces the risk of reinfestation.

Kragenfäule (Phytophthora cactorum)

If a malus loses its fruit stock early, this can be due to the collar rot. This fungal infection occurs more frequently, especially in grafted specimens and in the varieties “Cox Orange” and “James Grieve”. High temperatures and humidity also favor an infestation. If one or more characteristics are present in addition to the premature drop in apples, collar rot is probably the cause:

• slow dying of the branches
• parallel to the fruit drop also leaf loss
• dried bark with cracks
• Discolouration on bark and grafting points

What to do?

• If collar rot is detected, collect fruit that has fallen off immediately and remove affected parts of the plant
• ensure drier soil conditions: remove bark mulch if necessary

calyx and core rot

Calyx/seed rot caused by the sac fungus “Botrytis” can begin as early as spring. The treacherous thing is that it can cause a lot of unripe fallen fruit, but otherwise there is nothing to indicate an infestation until an apple is cut open. Then a rotten core area and white-yellowish Meysel coatings of the seeds appear.

What to do?

If the apple tree loses unripe fruit, a fallen specimen should be cut open immediately to look for typical features inside. If these are present, only a fungicide can help. The prerequisite is that the fungal infection is detected early. If it is not discovered until autumn, the only option is to cut back vigorously to strengthen the apple tree.

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