The carpocapsa is a parasitic insect, called cydia pomonella; its parasitic action is mainly carried out on apple and pear trees, but these insects can occasionally also attack cherry trees, medlar trees or other fruit plants. They are tiny butterflies, belonging to the group of tortricides, which lay their eggs at least two or three times a year, on the leaves of the trees, or directly on the ripening fruits. Once out of the egg, the larvae dig a tunnel up to the center of the fruit, where they remain to feed on the pulp; generally they spend their life near the seeds, which are also devoured or ruined. Fruits affected by this insect's larvae often fall off before ripening, or rot quickly when harvested. They would still be inedible, given the presence of the tiny worm inside them.
These insects carry out about three reproduction cycles during a fruit ripening season. The mature larvae spend the cold months inside a thick cocoon, inside which they can bear even the frost; the cocoons are produced in shelter, under the scales of the bark, among the dry leaves, in ravines of all kinds. As soon as the climate becomes mild, the larvae pupate and the adults emerge from them, around April or May. Mature females lay their eggs individually, on the leaves located near the flowers or small fruits. The first generation larvae from the leaves pass on to the fruits, and consume them from the inside, more or less towards the end of May. In July these larvae will be ready to produce the second generation of larvae, whose eggs will be laid directly on the peel of apples and pears. If the climate is particularly hot, the second generation larvae, after having ruined the fruits, enter a sort of rest period, finding a place to overwinter; if the climate is favorable, the second generation larvae will give rise to a third generation, which will carry out its action in September.
These insects cause serious damage to the orchard, as the affected fruits fall or rot; a single female can produce up to 60-80 eggs, so it is easy to understand how a large population of butterflies of this species can destroy an entire apple or pear crop. The fight takes place as soon as the presence of adults is noticed, in early spring. Pheromone traps are used to keep the presence of carpocapse under control: if adults are collected, the necessary treatments are applied to eradicate the larvae. Products that kill the eggs are used, immediately after flowering, and after a couple of months. For total safety, treatments that kill the larvae are also practiced, to be practiced more often, from when the plants have finished their flowering, until the end of summer. It is also important to practice late treatments, to prevent the surviving larvae from wintering, waiting for the following year.
The products for the fight
Fundamental to the fight against carpocapsa are pheromone traps: as soon as there are at least two adults a week in the traps, it is necessary to carry out a treatment against the blackberry eggs. In the family orchard there is generally a tendency to avoid the use of chemical products, in this case it is quite useful, to contain the butterfly population, to apply trap bands to the trunks of the trees: the larvae will find a valid shelter on these bands in autumn. in cardboard, and towards the end of autumn they can simply be removed and destroyed. In recent years, the method of sexual confusion has also given some results: the introduction into the environment of large quantities of sexual pheromone causes the difficulty of males to find fertile females, with the consequent impossibility of practicing mating. For the chemical fight, there are also products suitable for organic farming, as they are harmless to other insects. Against the carpocapsa a mushroom is also used, in autumn, which kills the hidden larvae waiting for spring.