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Codling moth: damage pictures and control methods

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Author: John Pratt
Date Of Creation: 9 April 2021
Update Date: 1 July 2024
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Codling Moth Control - organic method for Apple trees
Video: Codling Moth Control - organic method for Apple trees

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The caterpillars of the codling have liked to eat apples

Codling moth: damage pictures and control methods

The proverbial worm in the apple is by no means an invertebrate, but the larva of a butterfly, the codling moth (Latin Laspeyresia pomonella). The dreaded pest spreads quickly and threatens to destroy whole crops. Fortunately, the moth and its voracious offspring can be well-controlled with biological measures.

quote: The brightest apple contains the largest worm.

Appearance of codling moth

The adult moth is very small with a length of only one centimeter and also has an inconspicuous color. The gray-colored cover wings (forewings) are provided with wavy, dark transverse lines, also located on the outer edge of a characteristic red-brown spot. The slightly glossy hind wings are colored monochrome gray brown. Male and female animals hardly differ from each other in appearance.

From the whitish, only about one millimeter large, individually deposited eggs hatch up to two millimeters long, whitish caterpillars. These change their appearance in their further development and are later pink and up to two inches long. Also typical of older caterpillars are the dark warts and the dark brown head and neck shield. The brown doll is again quite small with about eight to ten millimeters in length.


Similar looking pests

For countermeasures to be successful, the nature of the pest on the apple tree must be established. There are a few species that are quite similar in appearance and / or appearance to the codling moth. However, these are sometimes combated with other means and / or at other times than this. The following table provides an overview with clear differentiators.

Occurrence and distribution

The codling moth - sometimes referred to as apple spinner - threatens the fruit tree harvest almost all over the world. The species mainly attacks apple trees, but does not stop at pears, quinces, peaches or even walnuts. Depending on the region, and thus on the climate, the pest may go through up to two generations per year and multiply very rapidly in this way.

This is typical for the Lake Constance region, for example, but in other parts of Germany the codling moth is also appearing earlier and more frequently. This is due to the ever warmer temperatures in spring and summer, creating the ideal living conditions for the development of the Falters. For example, the time of flight has clearly pushed forward, as spring always starts earlier with mild temperatures.


Life cycle and biology

The caterpillar larva - which is often referred to as a fruit mound - hibernates under the barky tree bark of the apple tree, where it is embedded in a solid web. As soon as the temperatures are warm enough, usually this is the case from the end of April, the caterpillars mate and hatch as adult moths from mid-May.

Only a little later the female animals already lay their 20 to 80 eggs in the still young fruits. Again, two weeks later, the first larvae hatch and go to the food source: The animals feed on both the shell and the pulp and the kernels of the apple - the latter is incidentally a clear indication of an apple worm infestation, as the larvae of other pests do not do this.

After three to four more weeks, the caterpillars have eaten enough and go to the trunk of the apple tree to einzuspinnen in the bark and hibernate there. The growth of the codling larvae is strongly dependent on the temperature: If it is cooler than ten degrees Celsius, eggs and larvae do not develop. However, after a warm spring and in just such a summer, two or even three generations of the pest develop and cause huge damage.

harmful effect

The codling moth prefers for oviposition and nursery - of course - apple trees of different varieties. However, the species is also found on other types of fruit, especially in climatically warmer regions. Above all:

If the weather conditions in such a year are so favorable that the population and thus the infestation skyrocket, this proliferation extends over the next few years. During and after a warm, dry year preventive and combating measures must be carried out with particular care.

Tips

As a rule, prematurely attacked fruits have to be sorted out, but late-infested ones can often be used at least partially. In this case, cut away the damaged areas in the apple generously. However, these fruits are no longer storable.

Harming

An apple worm infestation is well recognized by the only a few millimeters large holes, which eats the larva into the delicate shell of the unripe fruit. Typically, it eats spirally from outside to inside to the core housing, which is also affected. Feeders and core casings are contaminated with brown stings, both of which are clearly visible when the apples are cut. Early infested apples usually fall off early.

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Where is the worm? Codworm caterpillar in an apple. Herbst 2019 #apfel #stalking #modellanlage #apfelwickler #interreg #agroscope

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So you prevent an infestation by the codler

As so often, targeted preventive measures can prevent the worst infestation. The basis for success is the knowledge about the life cycle and the biology of the codling moth in order to find the right moment.

Promote predators

One of the most important preventative measures is the promotion of beneficial insects and birds, because they like the codling moth - and many other pests - to feed. Make your garden bird friendly, for example by hanging (cat-safe!) Nesting boxes, set up feeding areas in winter and set up a bird bath in summer. Sparrows, various species of tits, blackbirds and other songbirds will be happy to settle with you.

In the insects, especially these species are effective predators of the codling moth:

In particular, the parasitic wasps of the species Elodia tragic, Ascogaster quadridentatus and Trichogramma enecator have proven to be good control agents. They are available from specialist dealers. The beneficials attach to small cards that you simply hang between the branches of the apple tree. This should be done as early as possible in the year so as not to make the infestation pressure so great.

Minimize wintering places

Especially the barky bark of older apple trees offers the codling moth perfect hiding places in winter. Therefore, you should treat it preventively:

In contrast to the freezing strainers, glue rings have no effect on the codling moth and are therefore not a suitable method for prevention or control. Instead, you can try it once with this ancient peasant trick, which also offers other advantages:

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Collect larvae

Between January and April, regularly check the stems of your apple trees for overwintering codling moth larvae or their pupae. Shake the trees because the animals fall to the ground and can be collected. During the growing season, infested fruit should be removed as soon as possible in order to hinder further development of the fruit maggots.

What can you do effectively against the codler?

In case of an acute or threatened attack with the codling moth biological or natural methods of control are recommended, as chemical sprays also threaten the harvest - after all, these are toxins that you would later eat with the apples. In addition, many insecticides are generally not approved for home and garden use.

pheromone traps

Pheromone traps are less suitable for direct control of the codling moth, but provide a very good impression of the actual infestation. In addition, you catch the male moths, which can no longer fertilize the eggs of the female animals in the sequence - ergo no offspring hatch.

Pheromones are sex attractants that are painted into a glue-coated sticky trap. The male butterflies confuse the scent with those of the females, remain sticky and can then be collected. And this is how the system works:

By the way, you can ask your local phytosanitary department when the codermakers start depositing their eggs.

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Today I was in an orchard on the way and I met a pheromone trap for the codling moth. That reminded me how I caught the pheromone dispensers and thought of the following. Plant protection products (PPPs) are effective and easy to use. But how about other means to protect plants? If you do not want to rely on pure organic, then the Integrated Crop Protection would be the best solution. This would make your own business more sustainable and environmentally friendly. Pheromone traps themselves represent a very good method for controlling and monitoring the number of pests such as the codling moth. The entangling method immediately interferes with the communication system between male and female individuals of an insect species. The widespread application of a scent cloud with a pheromone ampoule confuses male insects, reducing the size of the next generation. One should not forget to change the traps in time. #alinaquality #warming # apple curler #pheromone trap #integrated crop protection #psm

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granulovirus

However, the timeframe for treatment with granulosis virus preparations like Madex is very tight as you need to catch the freshly hatched fruit magmas on their way to the apple. This hike takes only a few days, which is why accurate control of flight times by pheromone trap is so important. Mostly, the midpoint of the flight is between mid-May and mid-June, which is why treatment with this biological agent also takes place at this time.

Granulosis viruses are effective against codling moths, but are harmless to bees and other beneficial organisms - not unimportant in fruit growing, after all, these insects are said to fertilize the apple blossoms. And so the preparations are applied:

    Mix the product exactly as per the package instructions. Fill it with a clean garden sprayer. Spray the whole tree carefully with it. Do not leave untreated corners as the caterpillars need to absorb the active ingredient directly. Repeat the application three times every eight days. Repeat them from the end of July / beginning of August to intercept the second generation.

Take treatment on a dry day when it is not rainy or windy. Both influence the result negatively.

nematodes

Also, nematodes of the species Steinernema feltiae have been shown to be effective against overwintering codling moth larvae. These are tiny nematodes that invade the larvae and kill them by means of a bacterial infection. And this is how the method works:

    Nematodes are sprayed after harvest. They should reduce the infestation pressure in the coming year. Ideal are damp weather (drizzle) and temperatures from eight degrees Celsius. Do not spray on sunny days, preferably in the evening nematodes are very sensitive to UV light spray all winter hides: trunk and branches, piles and rods, fruit mummies)

frequently asked Questions

What is the confusion technique and how does it help against the codling moth?

Confusion is caused by the already mentioned pheromone traps. Although these are well suited to the highlight of the codling moth flight and thus the right time to spray to have, but have only a minor impact on the population and thus the infestation pressure.

Can fight the codler with Neem?

Neem is indeed effective against many fruit pests, but not against the codling moth.

Are there effective home remedies for the codling moth?

Instead, you can use Wermutjauche as a proven home remedy. For this, pour 300 grams of fresh wormwood leaves with ten liters of water and let the mixture ferment in a plastic container for ten to 14 days. Only fermented vermouth is effective against the codling moth, while a simple infusion is not strong enough. Against the strong smell you can stir in a handful of rock flour. The spraying with wormwood must be done in the spring between mid-May and mid-June and best repeated several times.

Tips

For the vermouth, take dried herb instead of fresh leaves in the previous year. After all, you will not find any suitable wormwood so early in the year.