Cydia pomonella

Author: (Linnaeus, 1758)

Codling moth
larva: apple maggot

Species Overview:

Adult: 14-22 mm wingspan; general colouration of forewing plumbeous, with pronounced, transverse, dark brown strigulation and a large, distinctly coppery ocellus. Hindwing fuscous, in males with a submedian fold.
Egg: 1.3 x l.0 mm, lenticular, depressed, opalescent white with a red ring appearing during development; deposited singly, or rarely in groups of two or three, on or near the calyx of a fruitlet in early summer and later on the side of a young fruit, or occasionally on a leaf [Cydia pomonella egg ].
Larva: 18-20 mm long (full-grown); head yellowish brown or brown overlaid with a darker brown pattern, region of stemmata blackish; prothoracic plate yellowish brown mottled or lightly marked with a brownish pattern; abdomen yellowish white, becoming tinged with pink dorsally when fully grown, strongly shagreened; pinacula light grey; peritreme of spiracles black-brown; anal plate yellowish brown speckled with blackish, rounded caudally; anal comb absent; thoracic legs light brown [Cydia pomonella larva ].
Pupa: 8-10 mm long; yellowish brown to dark brown.

Taxonomic Description:

Male:

Cydia pomonella adult 1
Cydia pomonella adult 2
Cydia pomonella adults
External characters: 14-22 mm wingspan. Forewing ground colour white, suffused with plumbeous except tips of scales, producing a farinose effect, indistinctly striated transversely with dark brown, costa obscurely strigulated with dark brown, some of the interspaces producing faint plumbeous striae; fasciate markings dark brown; basal and sub-basal fasciae forming a diffuse, strigulated basal patch, its outer edge usually darker and moderately well defined, slightly oblique from costa to near middle, thence obtusely angled to dorsum; median fascia weakly developed on costa, obsolescent or obsolete dorsally; ocellus large and extending into subapical area, dark purplish brown, sometimes marked with black scales along radial veins, edged with thick coppery or golden metallic striae, the inner stria bordered by a slender, curved, black pre-tornal marking; subapical area often suffused with purplish black; cilia concolorous with wing basally, otherwise dark grey, with a blackish sub-basal line. Hindwing fuscous, darker terminally, with a shallow submedian groove or fold fringed above by a dark fuscous cubital pecten; cilia greyish white, with a dark fuscous sub-basal line (Bradley et al., 1979).

male genitalia Cydia pomonella
Genitalia: Notch in ventral margin of valva shallow, with small dent before cucullus. Aedeagus slightly bent in basal part, with small cornuti arranged in two unequal groups (two and four to six). Aedeagus about as long as valva to ventral dent.

Female:

External characters: Forewing colouration and markings similar to those of male.

female gen. Cydia pomonella
Genitalia: Ductus bursae broad (two to three times narrower than corpus bursae); ductus seminalis dilated and sclerotized near opening. Lamella postvaginalis a semi-square without anterior protuberances.

Variation:

Minor variation is found in the strength of the plumbeous suffusion and dark brown strigulation of the forewing ground colour and in the markings; in dark specimens the ocellar area is blackish purple and the coppery reflections are stronger. Often the general colouration is distinctly lighter. A rare light-coloured form has the forewing markings obsolete except for a vestige of the pre-tornal marking and the ocellus is reduced, the remainder of the wing being grey-brown and densely farinose (Bradley et al., 1979).

Biology:

overwintering larva in cocoon
The life cycle of the coddling moth, whereever it occurs, exhibits two special features:
- Overwintering always occurs as mature larvae diapausing in a cocoon sheltered situation on the tree or in the ground.
- The number of annual generations varies from one to four according to the climate (which depends on latitude and altitude), the year and sometimes the host plant. However, a certain proportion of larvae enters dispause in each generation. A regular absence of fruit during the developing second generation, for example on apricot, has the direct effect of preventing larval growth and the indirect effect of gradually producing a race that has much higher proportion of diapausing larvae in the first generation.

Host plants and damage:

Apple (Malus)

bore-holes in apple
Cydia pomonella is an important pest of apple. At first, an invading larva (typically one per infested fruit) forms a small cavity just below the fruit skin and after feeding for a few days burrows down to the core, leaving a prominent, red-ringed entry hole in the side or near the eye, characteristically blocked by dry frass. Within the fruit, the larva eats away a large proportion of the flesh and also attacks the pips, the cavity becoming filled with brown frass. The entry point at the surface is greatly enlarged as tissue is eaten away and the larva eventually escapes leaving a small, unplugged exit hole. Sometimes a larva will attack another fruit in the same cluster before becoming full-grown, damaged fruits tending to ripen and drop prematurely. Attacks can be serious, especially following the appearance of a second generation of larvae, and are often most severe close to stores and packhouses and on trees near piles of empty boxes which held the previous season's crop. Infestations of codling moth occur later in the year and in larger (older) fruits than attacks of fruitlet-mining tortrix moth or apple sawfly; also, there is little or no external accumulation of frass, most remaining within the larval gallery (Barnes, 1991).

Pear (Pyrus)

Larvae cause similar damage on pear (Pyrus communes, Pyrus pyrifolia) but attacks are rarely as heavy (Barnes, 1991).

Walnut (Juglans)

In early season, larvae enter through the calyx and feed on the developing seed, and the nutlet falls to the ground. As the shell hardens, entry to the seeds is exclusively through the fibrous tissue at the stem end. The searching and pre-entry behavior of neonate larvae is quite prolonged on walnut. Evidence of feeding around the base of walnuts may be extensive, without larval entry occurring.
Not all varieties of Juglans regia are equally susceptible to the codling moth. Early-maturing varieties as 'Payne' and 'Concord' were found to be susceptible, and in the same trial, in a light infestation, 'Franquette' and other late-maturing varieties had only trace infestations. However, in some seasons the 'Franquette' variety may be seriously infested, although it usually exhibits a marked degree of resistance. In extensive monocultures of 'Payne' walnuts, the codling moth does not cause noticeable damage until 2 or 3 years after initiation of bearing, although trace populations are present in the orchard. This may be attributed to the fact that the bark of young walnut trees is very smooth and offers little shelter for cocoons for hibernation. The requirement of mature larvae for such shelter (cracks and crevices in the wood, exfoliating bark, etc.) is a host-regulated, upper limitation on their survival to pupation.
The 'Hartley' variety has a low level of infestation because pubescence remains on the nutlets until they are too large (Barnes, 1991).

Quince (Cydonia)

Plantings of quince, Cydonia oblonga, are often reported as harboring relatively low infestations of codling moth, especially in monocultures. Higher infestation may occur when quince are planted adjacent to or in mixture with apples and pears. Young quince fruit are highly pubescent, and this is thought to be related to the suppression of establishment of first generation larvae (Barnes, 1991).

Apricot (Prunus armeniaca)

damage on apricot
Although the apricot (Prunus armeniaca) is extensively planted in areas of the temperate zone with relatively mild climates that are otherwise quite favourable to the codling moth, only occasionally does a race develop which infests them to a significant degree. Trace populations are encountered more frequently (Barnes, 1991).

Plum (Prunus spp.)

In southern California, Smith, 1940, recorded 50 % infestations in 'Kelsey' orchards. His observations indicated that a selection favoring a univoltine strain had taken place on this plum variety, in a region where the codling moth is bivoltine in apple orchards. In 1963 the 'Late Santa Rosa' and 'Kelsey' cultivars were first observed to be suffering relatively severe losses from codling moth in the San Joaquin Valley (Northern California).
The codling moth has also demonstrated its ability to develop and maintain infestations in orchards of at least two varieties of so-called Japanese plums, Prunus salicina. The European plum (Prunus domestica) and the damson, Prunus insititia, are apparently of little or no importance as hosts for the codling moth (Barnes, 1991).

Peach and nectarine (Prunus persica)

Records of infestation by codling moth on peach, Prunus persica, or nectarine, which is a peach with recessive genes that confer a smooth fruit surface, appear to be entirely related to the presence in the near vicinity of apple, pear, walnut or apricot trees. Even in areas where there is an admixture of pome and stone fruits, low population levels are reported on peach. In monocultures, infestations appear to be extremely low to non-existent.

Other Prunus species

Sweet cherry, Prunus avium, has been recorded as a host of codling moth. However, reports may have been derived from a single reference. No note was taken of the proximity of pome fruit trees, from which these infestations were no doubt derived at a time when codling moth control depended on arsenicals. There is no evidence that populations are maintained in cherry orchards. Infestation is in the flesh of the cherry and favours infection by decay organisms. While the direct damage caused by codling moth is negligible, restraint of trade by quarantine may have an economic effect.
Fruit and leaves of the sour cherry, Prunus cerasus, are unattractive as oviposition sites. Soft-shelled varieties of almond, Prunus amygdalus, adjacent to apples and pears may have a low level of infestation, largely derived from the second brood (Barnes, 1991).

Other hosts

Castanea sativa, Ficus carica, Sorbus

Distribution:

Europe and Northern Africa to Russia. Originating probably from the Palaearctic Region, the codling moth is now found in most temperate regions of the world where apples are grown, including China, North America, South America, South Africa, Australia and New Zealand.

Pheromone:

effluvia
E 8E 10-12OH : 5.4 *
E 8Z 10-12OH : 0.3
Z 8E 10-12OH : trace
E 9-12OH : 0.8
10OH : 0.15
12OH : 3.5 *
14OH : 0.5
16OH : 1
18OH : 1.2

gland
E 8E 10-12OH : 2.1 *
E 8Z 10-12OH : 0.08
Z 8E 10-12OH : 0.01
E 8E 10-12Al : 0.02
E 8E 10-12Ac : 0.005
E 9-12OH : 0.2
10OH : 0.05
12OH : 1 *
14OH : 0.2
16OH : 0.04
18OH : 0.08
18Ac
20Ac

Components marked with * are involved in attraction (Arn et al., 1985).

Parasitoids:

of egg:
Trichogramma evanescens Westwood
Trichogramma embryophagum Hartig
Trichogramma embryophagum cacoeciae Marchal
Trichogramma minutum Riley
Trichogramma dendrolimi Matsumura
Trichogramma turkeiensis
Trichogramma kilinceri
Trichogramma buluti

of larva:
Ascogaster quadridentata Wesm.
Pristomerus vulnerator Panz.
Pristomerus austrinus T. and T.
Calliephialtes nucicola Cush.
Lixophaga variabilis Coq.
Microdus rufipes Nees
Neoplectops pomonella Schnabl.

of overwintering larva in cocoon or pupa:
Cryptus sexannulatus Grav.
Hemiteles carpocapsae Kok.
Apistephialtes caudatus Ratz.
Apistephialtes cydiae Perk.
Pimpla spp.
Trichomma enecator Rossi

Furthermore, in Russia, Pleisthophora carpocapsae Simchuk and Issi (Microsporidia, Nosematidae) was found in larvae and pupae of Cydia pomonella.

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