The Content Of The Article:
- Recognition of an infestation
- The life cycle of the codling moth
- Prevent codeworm infestation
- Pheromone traps against codling moth
- Biological control of codling moth
The codling is by far the most common pest on apple trees. The brown-gray moths have a span of almost two centimeters and have light stripes and a copper-colored spot at the end of the wings. They are particularly active in the twilight at temperatures below 20 degrees. The hatched caterpillars are only two millimeters long, white or yellowish with a dark head. In the last stage of development they grow to one and a half to two centimeters in length.
Recognition of an infestation
An apple-worm infestation is easily recognizable on the only a few millimeters large drill hole in the shell of the immature apples. The caterpillars of the inconspicuous moths eat themselves spirally from outside to inside through the pulp and contaminate the feeding passages and the core housing with unappetizing kills. Affected fruits fall prematurely or are no longer storable and must be recovered quickly.
The life cycle of the codling moth
The caterpillar of the codling overwinters directly under the bark scales of the apple tree in the tree bark in a tight web. At the end of April there is pupation, from mid-May the first moths hatch.
The codling usually occurs in two generations per year. The larvae overwinter in bark crevices. In the spring the adult moths hatch. In May the females lay their eggs on the young fruits. The newly hatched larvae are boring into the fruit. In July, they leave their dwelling, migrate to the tribe and pupate. At the end of July, the second generation of moths starts and lays eggs again
A short time later the females lay their 20 to 80 eggs individually on the young apple fruit. The codling eggs have the shape of oval, shiny shields. After about two weeks, the first caterpillars hatch and crawl to the food source. They feed on both the apple peel and pulp and kernels. After three to four weeks, the caterpillars leave the fruit again and crawl back to the trunk, where they overwinter under the bark in the pupated state. Since the moths usually appear in two or more generations over the year and eat the fruits in their different degrees of ripeness, the crop damage is often considerable.
After three to four weeks, the caterpillars leave the fruit again and crawl back to the trunk to overwinter under loose bark pieces in the pupated state
Overall, the growth of the fruit maggots is strongly temperature-dependent. Under ten degrees, the eggs can not develop, so the pests with oviposition and pupation react very flexible to temperature fluctuations - which makes it difficult to find the optimal time for the fight.
Prevent codeworm infestation
In winter and spring from January to April, fruit tree strains should be examined for pupated codling larvae. Regular shaking of the trees followed by thorough collection of the larvae significantly reduces the population. Infested apples should be removed as soon as possible.
The bark of older fruit trees offers the pests a perfect winter home. Brush the stems of the older fruit trees with a hard brush, a small hand pick or a special bark scraper. But do not press the metal scrapers too hard: the devices should only loosen the loose pieces of the bark and not hurt the bark.
The caterpillars of the first generation migrate from the end of June to pupation to the trunk of the apple tree. Attach a corrugated board belt at a height of 50 centimeters there
From the end of June the corrugated belt will be used. Simply wrap a 10 to 20 cm wide strip of corrugated cardboard around the trunk and fasten. The first generation caterpillars crawl into the cardboard to pupate there. Existing poles should also be wrapped in cardboard and checked traps weekly. At the end of September traps will be removed, along with the caterpillars that have settled in them. Glue rings have, in contrast to frost scraper, against the adult codling no effect!
Pheromone traps against codling moth
The number of male moths can be reduced between May and August using commercially available perfume traps. They contain a capsule with a sex attractant. The codling males are attracted to the attractant and stick to the glue in the trap. This reduces the number of fertilized females and thus the number of fertilized eggs. The males, however, are not decimated by the traps so much that they no longer propagate - so use the pheromone trap to determine when the climax is the moth. Thus, you can estimate the oviposition and the appearance of the first caterpillars well. One usually hangs a trap in every tree at the beginning of May.If there are more than five butterflies per week, start with the first granulosis virus spray (see below). The local phytosanitary department also provides information about when the codermakers are active and start oviposition.
Attractor traps are covered with a glue inside which the male butterflies stick. Above all, they provide good control over the activity of the male codling moth
Biological control of codling moth
The granulosis virus concentrate is diluted in a sprayer with water (left) and then sprayed into the crown of the apple tree (right). Be sure to thoroughly wet all leaves and shoots
Biological control with granulosis virus preparations (for example "Madex Max") is very effective in catching the newly hatched caterpillars on their way from egg to fruit. Since this hike takes only a few days, it's difficult to get the timing right. This is where the pheromone trap helps, because it helps to determine the altitude of the moths. Depending on the climate and weather, it is between mid-May and mid-June. Mix the biological preparation exactly as per the package instructions. It is especially effective against codling moths, is safe for bees, beneficials and other living things and is also used in organic farming. With the help of a conventional clean garden sprayer you bring out the mixture and spray the whole tree thoroughly with it. Because the larvae must directly ingest the drug, the granulosis virus, before drilling into the fruit, and because new animals hatch on a regular basis, the application must be performed three times every eight days or so. In warm summers and regions, a second generation is developing. Therefore, the procedure is repeated from the end of July / beginning of August. Timely suspended adhesive traps provide information about the degree of infestation and the correct time of injection.