Codling moth : biological control , effective remedies and insecticides recommended by agronomists. How to eliminate the codling moth from apple and pear trees .
Its scientific name is Cydia pomonella . It is a small butterfly (a lepidopteran) very harmful to fruit growers: it attacks pear and apple trees . The female Cydia pomonella lays its eggs in the fruit. The eggs, once hatched, give rise to the development of worms (larvae) that feed on the fruit.
The worms (Cydia larvae) tunnel to the seed area. The affected fruit does not show signs of egg deposition but has holes made by the developing larvae.
If you pick pears and apples in your garden with worms , this parasitic insect could be the culprit.
Cydia pomonella or Codling Moth
The larvae of Cydia pomonella are whitish with a dark head. They become yellowish during growth until they turn red. The adult codling moth is, instead, a small butterfly. The wings have transverse bronze streaks.
Codling moth larvae damage the fruit, dig tunnels that fill with excrement. The larvae live in apples or pears until terminal development and reaching the adult form.
Due to the damage, you will not only end up with pears and apples with worms , but also fallen fruit: the fruit detaches from the tree prematurely.
Affected fruits
This parasitic insect can infest many fruit trees and attack:
- Apples
- Pears
- Walnuts
- Peaches
- Medlars
- Plums
- Apricots
- Cherries
- Khaki
- Pomegranates
The most susceptible varieties are the Staiman Red and Red Chief apple , and the Abate Fètel and Kaiser pear . Of the pear, the Decana and Pacham’s Triumph varieties are less likely to suffer damage from Cydia pomonella.
Codling moth: biological control
Integrated pest management is carried out by first monitoring using pheromone traps to determine the density of adult males and apply appropriate defence measures.
In biological control, preparations based on a virus, Cydia pomonella GV, are being spread and a practice of “sexual disorientation” is being exploited to avoid mating. Disorientation is performed using pheromones. Pheromones are widely used in agriculture in biological control.
Microbiological control is carried out using the Beauveria bassiana fungus.
Insecticides for codling moth
Many of the insecticides used in the past to eliminate codling moths are now “banned” and used only in cases of particular exemptions (insecticides such as Fenitrothion, Chlorpyrifos-ethyl, …).
Insecticides are used today as an integration to biological control . Treatments with different active ingredients permitted in the integrated production specifications are possible. It is useless to carry out treatments with the active ingredient “pyrethrum” as they are effective only by contact with the parasite .
Spinosad shows some effectiveness. This product is diluted in water and applied with a spray dispenser: it should be used before the appearance of insects, repeating the treatment after 15 days (2 treatments).
Effective remedies against Cydia pomonella
Among the most effective remedies , we are not talking about insecticides or biological control but mechanical remedies . A French research has found that in order to be fertilized by males, the female codling moth must first witness the so-called “nuptial flight”.
For many animals, the courtship ritual is fundamental. Some show their tails, others dance. Female codling moths perform a vertical nuptial flight and if they fail to complete it, they will end up laying sterile eggs and so no worms in the pears and apples!
To prevent this nuptial flight, it is possible to use nets to fight codling moths and other insect parasites of apple and pear trees.
This French research has highlighted an important discovery that has enlightened the world of organic farming . Initially, in fact, the adoption of nets was first “tested” among organic fruit growers and then spread to all producers, including those who grow pears and apples with the traditional method. In short, nets for fighting Cydia pomonella would be preferable even to conventional insecticides .
Nets for controlling codling moths should have a mesh size of 2×5 mm. They can be installed in a single block or in a single row, as long as the net touches the ground.
