Hemm cidia of the plum tree (Cydia funebrana) huwa insett li jappartjeni għall-ordni Lepidopterafamilja Tortricidae. This parasite is also commonly known as plum moth u plum worm. The entomological classification is the same as for three other Lepidoptera with similar characteristics, namely the Eastern peach moth (Cydia harasses), Il cobweb of the apple tree (Cydia pomonella) U l- chestnut worm (cydia splendana). The tortricide Cydia funebrana it is probably native to central Europe, and is currently widespread in Italy.
If not properly controlled, this cidia can compromise the whole plum tree cultivation of the year. However, fortunately, there are biological techniques to limit their proliferation, and in this article we find out what they are.
Description of the cidia of the plum tree
Hemm Cydia funebrana, when adult, it is a small butterfly, with a wingspan of 14-16 mm. It has grayish front wings, with a blackish-brown background and whitish marbling.
Bajd
The egg is lenticular in shape, initially opalescent in color, then yellowish. Measures 0.75 x 0.6 mm.
Larva
The larva, that is the plum tree worm, at full maturity measures about 12-15 mm. The color is carmine red, the head is dark. The pronotum presents, clearly visible, some dark spots. The abdomen has 4 dorsal hair warts on each segment.
Chrysalis
The chrysalis is light brown or reddish in color. It has the end adorned with a dozen small spines and the cremaster equipped with hooked bristles. Measures 6-7mm in length.
Plants attacked by the cidia of the plum tree
Hemm Cydia funebrana is a parasite that almost exclusively affects the plum tree, attacks on other stone fruit, such as ħawħ, berquq u Siġra taċ-ċirasa.
How to notice the presence of the cidia
The attack on the fruit by the larvae of the Cydia funebrana it is recognized by the escape of rubbery substances from the inlet and outlet holes. Another symptom is an early coloration concentrated only in one part of the fruit.
The damage of cidia on plums
The damage of the cidia is concentrated on the fruits, in particular on the pulp, on which the larvae feed. It is necessary to distinguish the damage on immature plums (first generation) from those on ripe fruit (subsequent generations).
On the newly attached plums, the larvae dig a direct tunnel to the point of attachment of the peduncle, causing the fruit to fall off prematurely.
On nearly ripe plums, the larvae tunnel around the core. If the ripening of the affected fruit is far away, also in this case, the fruit falls. Otherwise, on ripe plums, the worm will be encountered at the time of consumption.
Ħsara indiretta
The attacks of Cydia funebrana they can also cause indirect damage. The holes dug by the larvae represent the entry route for dangerous fungal pathogens, in particular the agents responsible for monilia of the stone fruit.
Varieties of plum trees susceptible to cidia
The plum cultivars most susceptible to attacks by the cidia are those with late ripening, for example the varieties President, Stanley u anġlu.
Life cycle of the plum tree cidia
The cidia of the plum tree spends the winter at the stage of mature larva in diapause, usually taking refuge within the scales of the bark of the tree. In March-April these larvae crystallize, with the first flight of the adults occurring in the phenological phase of post-setting, when the plums are larger than a cherry stone. From this moment, the flickers are continuous until the end of May or the beginning of June.
Fertilized females lay eggs for about a month. The eggs, 60-80 on average, are laid more or less isolated on the lower half of the drupes.
Embryonic development occurs in 9-18 days, depending on the temperatures.
L-ewwel ġenerazzjoni
As soon as they are born, the first generation larvae penetrate the fruit. They reach maturity in 24-32 days inside plums that have now fallen to the ground, and then crystallize in the trunk of the tree or on the ground. New adults flicker after 10-13 days.
It-tieni ġenerazzjoni
The flight of the second generation therefore takes place from mid-July and throughout August. These larvae have a shorter embryonic development, 6-11 days, and reach maturity in 20-24 days. These are also the larvae that survive the winter by creating a silky cocoon inside a safe shelter.
In particularly favorable years from the weather point of view, there may even be 3 generations.
Natural antagonists of the plum cidia
Fortunately, there are gods in nature insetti ta’ benefiċċju which limit infestations of Cydia funebranain particular parasitoids: Trichogramma spp. u Dibrachys cavus (chalcidoid hymenoptera), Ascogaster quadridentatus (braconid hymenoptera), Lissonota artemisiae (Ichneumonid hymenoptera).
How to prevent plum cidia
The biological defense strategy against the plum cidia must be carefully thought out. First of all, if you have not yet planted your plum trees and you are aware of the presence of this parasite, orient your choice towards early ripening cultivars, less susceptible to late ripening ones.
The defense of the fruits begins with the monitoring of the flight of the adults, with the nases tal-feromoni to be installed in the orchard in April. In a small orchard, even a single trap is enough. Obviously, when buying from the best agricultural consortia or online, you must ask for the trap with specific pheromone for Cydia funebrana.
How to eliminate the cidia of the plum tree
Keep in mind that the first larval generation does not generally require interventions with specific treatments. As mentioned, the damages are limited and cause fruit drops. More attention, on the other hand, must be paid to the second generation, the one capable of infesting ripening plums. In this case, an intervention threshold is established: if the capture in pheromone traps exceeds 10 individuals per week, then interventions based on bacillus thuringiensis var. kurstaki that misjuba fi ħwienet speċjalizzati.
The treatment tries to hit the larvae and must be repeated if necessary, always following the flight of the adults and taking into account the times of embryonic development.
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