Codling moth

Cydia pomonella

Profile

Codling moth is one of the most important animal pests in apple production, but is also significant in pear and walnut production and can cause significant crop losses.

Appearance

The codling moth belongs to the moth family (Tortricidae) among small butterflies. It has gray-brown forewings with irregular whitish stripes and a dark, golden shiny spot (eyespot) near the wing tip. The hind wings are uniformly light brown, the wingspan is about 20 mm.

The caterpillar (fruit maggot) has a brown head and is initially yellowish white, later pinkish yellow in color. It has a total of eight pairs of legs, including three jointed pairs on the thorax and five unjointed pairs on the abdomen, and grows up to 20 mm long.

Biology

The flight activity of the first generation begins in May during apple blossom and lasts until the beginning of August. The flight takes place mainly in dry, warm and windless weather. The females lay the silvery eggs on fruits and leaves. After a few days, the caterpillars hatch and bore into the still small fruit through the depression at the base of the flower or on the stem, first under the fruit skin, until they later penetrate into the core and destroy it by their feeding activity. In the process, they leave behind crumbs of excrement in the feeding tunnels, which also partially swell out through the borehole. Three to four weeks later they leave the fruit and spin themselves into a white cocoon under bark scales and other tree hiding places. Some of the caterpillars pupate and develop into second-generation moths (beginning around the end of July), while the others go into dormancy (diapause) and overwinter. The first generation overlaps with that of the second generation, which lasts from late July to early September. The eggs of the second generation are laid on fruits, the caterpillars are found in the ripe fruits. The older caterpillars leave the fruit via spider threads and overwinter in a cocoon in bark cracks on the trunk or in the ground. Pupation does not occur until the following spring.

There are two generations per year, in warm and dry areas sometimes up to three generations are possible. At higher altitudes and where the necessary temperatures for pupal development are not reached, there is only one generation.

Damage symptoms

A borehole filled with fecal crumbs is visible in one part of the fruit. Inside the fruit there is a feeding tunnel that leads to the destroyed core, which usually still contains the caterpillar. Infested fruits become not ripe and fall off prematurely.

Host plants

Codling moth occurs on apple, pear, and walnut, and occasionally on apricot, plum, peach, and quince.

Distribution

Codling moth is found all over the world.

Propagation and transmission

Codling moth can itself actively seek out suitable host plants by flight and reach other orchards.

Economic importance

Codling moth can cause significant crop losses due to the feeding activity of the caterpillars in the fruit. It is the most important pest in apple growing.

Damage caused by codling moth is often followed by monilia blight.

Prevention and control

  • Promotion of natural counterparts (e.g. birds)
  • Picking up and destroying fallen fruit regularly
  • Attach corrugated cardboard rings to tree trunks beginning in July to trap overwintering caterpillars hiding there and then remove and destroy them with the corrugated cardboard.
  • Use of pheromone traps to detect the onset and flight of moths.
  • In larger, uniform plants, pheromones (sex attractants) can be applied before the moths begin to fly so that sex finding is prevented (confusion method). As a result, there are no fertilized eggs and no infestations occur.
  • Targeted treatments of pome fruit trees with plant protection products approved for codling moth control (see list of plant protection products approved in Austria) . It is essential to pay attention to the correct treatment time and waiting period! The exact treatment dates are announced by means of warning service messages.

Fachinformation

Publikationen

Lethmayer C., Hausdorf H., Altenburger J., Blümel, S., 2009. Trials of alternative codling moth (Cydia pomonella) control strategies in Austria. International Journal of Fruit Science, 9, 1–9.

Last updated: 04.11.2021

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