Apples with a worm crawling out of them can often be seen in children’s books or illustrations. Unfortunately, this idea is also not uncommon in reality. But then the animal inhabitant only spoils the appetite. Many a gardener wonders whether an infected apple is still edible. Or is the enjoyment even dangerous for people who discover the worm too late and eat it with the apple?
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pest picture
The often encountered worm in the apple, also called the fruit maggot, is the codling moth caterpillar . Cydia pomonella is one of the most common pests of fruit trees. In the adult stage, the gardener recognizes the gray moth with a wingspan of up to 2.5 cm by its light gray stripes and the copper-colored spot on the wing tip. The females are particularly active in early summer from May to June and sometimes lay 30 to 60 eggs on the leaves of the Malus. The following weather conditions promote the population:
- humid air
- calm
- mild summer evenings with temperatures of 20°C
From July, when the first apples ripen, oviposition shifts from the leaves to the fruit. Here the maggots hatch after a short time and immediately find a source of food. While they stay on the apples for about three to four weeks, they bore through the skin and eat their way through the flesh up to the core. In doing so, they excrete brown, floury faeces, which later clearly shows the infestation when the apple is cut open.
The larvae then pupate, leave the apple tree as moths for a short time and finally return to lay eggs on Malus again. This cycle produces a second generation in August and September respectively. The latter causes even greater harvest losses, since the apples are almost completely ripe by this time. In this phase, the apple tree is no longer able to counteract the pest on its own.
Recognize the worm infestation
Malus reacts to Cydia pomonella by dropping infected fruit. Unfortunately, the gardener very rarely recognizes this sign, since wind or other circumstances at that time also separated apples from the tree.
Evidence of the mealy droppings is just as difficult to find from the outside. Small puncture marks can have many causes. In addition, those caused by the codling moth are often tiny, since the larvae are also only small in size. Even apples that look healthy on the outside can contain the worm.
Infested fruit – edible or dangerous?
It is precisely the small body size that makes the grub of the codling moth harmless for use. The worm is not dangerous, does not transmit diseases, nor is it poisonous itself, and you can eat the apple with it. Every now and then the gardener doesn’t even notice that he’s eating a small maggot in the apple. However, the brown feces have a very bitter taste and make the fruit inedible. When using as juice or applesauce, the gardener should generously remove rotten spots with a knife beforehand. If several fruits of a certain tree show symptoms of the codling moth, the rest of the harvest is only conditionally suitable for raw consumption. To be on the safe side, cut the fruit before use.
countermeasures
When the worm is literally in there, many gardeners tend to abandon their apple tree and cut it down. But that doesn’t have to be the case, since the codling moth is not a disease, but a pest that can be driven away. The following control measures reduce the population:
- collect fallen fruit
- pick rotten apples
- scrape off the bark in winter
- Be careful not to damage the tree trunk
- attract natural predators into the garden (e.g. parasitic wasps or earwigs)
Ichneumon wasps are available in bags from specialist retailers. However, it can only be used for a limited time. Provide the insects with a shelter in the form of an insect hotel.
