Author: (Walker, 1864)
South-African carnation tortrix
African carnation tortrix
Species Overview:
Adult: 17-20 mm wingspan; forewings of both sexes yellowish to reddish-brown, merging into dark reddish-brown or blackish towards dorsum; lighter areas noticeably speckled with brownish-black; hindwings light grey.
Egg: deposited in elongate clusters of about 25 eggs [E. acerbella egg batch on bud ].
Larva: 15 mm long; green to yellowish, with dark green dorsal and subdorsal lines and whitish pinacula; head greenish brown, marked with brownish black; prothoracic plate green marked with black along the lateral margin and above the prothoracic spiracle [E. acerbella larva - green ; E. acerbella larva - yellowish].
Pupa: dark brown; in a silken cocoon spun between leaves [E. acerbella empty pupal skin ].
Taxonomic Description:
Male:
Epichoristodes acerbella adult
Epichoristodes acerbella male
External characters: Antenna short-ciliate. Forewing without costal fold; elongate, hardly dilated; costa gently arced throughout; apex obtuse; termen nearly straight, rather oblique. Ground colour yellowish to reddish-brown, merging into dark reddish-brown or blackish towards dorsum; lighter areas speckled with brownish-black; dorsum with ill-defined dorsal blotch; hindwings light grey (Diakonoff, 1960; Alford, 1995).
male genitalia E. acerbella
Genitalia: Uncus long, curved; socii large, long-bristled; gnathos hooked, transtilla entire; valva semi-oval, simple; sacculus short, with well sclerotized ridge; aedeagus pistol-shaped.
Female:
E. acerbella female 1
E. acerbella female 2
External characters: Forewing markings hardly discernable or absent
female gen. E. acerbella
Genitalia: Sterigma broad, lamella postvaginalis weak. Antrum long, tubular. Signum smooth, obtuse.
Variation:
The darker dorsal blotch on the forewings can also be hardly discernable or absent in males.
Judging by the original descriptions of iocoma (now synomized with acerbella) the blackish spots on the forewing can also be absent.
Taxonomic note:
When Diakonoff, 1960, described the genus Epichoristodes, he divided the genus in two subgenera, Epichoristodes and Tubula , based on differences in genitalia; acerbella was described in Tubula. In the subgenus Epichoristodes, the transtilla is divided into two sclerotized dentate parts; inTubula the transtilla is entire. Female genitalia differ in the development of the lamella postvaginalis.
According to Horak, 1984, the divided transtilla is a derived character in Archipini. The simple bandlike transtilla has undergone a series of transformations, finally resulting in the bipartite, dented transtilla as is known from the subgenus Epichoristodes. I therefore think that Tubula should be treated as a separate (non-related) genus; however, acerbella is still included in Epichoristodes in this work.
Biology:
Epichoristodes acerbella has four generations per year, between April and October, on host plants in the open air in France, Italy and Spain. The threshold of development is about 6°C. However, the overwintering larvae are able to withstand lower temperatures. In glasshouses the number of generations is higher, but they are difficult to distinguish, since all stages are present during most of the year.
Females usually start to oviposit about one day after mating. The eggs are laid on the upper surface of the leaves in batches of about 25. Each female produces 200-240 eggs during her life span. The eggs hatch after about 10 days. Larvae feed for about 4-8 weeks, sheltering within rolled leaves, which they spin together with silk. Pupation occurs within a silken cocoon spun between the leaves (Van de Vrie, 1991; Alford, 1995).
Host plants:
Epichoristodes acerbella is mainly a pest of Dianthus (carnation) but has also been recorded from Chrysanthemum, Erigeron, Fragaria, Gerbera, Malus, Medicago, Prunus, Pyrus, Rhamnus, Rosa, Rumex and Sonchus.
Damage:
early sign of damage Dianthus
Because it is polyphagous, Epichoristodes acerbella may cause damage to a range of crops, but it is most important on carnation. Mediterranean cultivars seem to be more susceptible than American ones. The larvae make tunnels in the plant tissue. When they make these tunnels in stems, the leaves often desiccate. Frequently, larvae infest carnation flower buds and open flowers and feed on the most central part of the buds. The petals are woven together with silk. Greenish larval excreta are often present in or on affected stem tissues. In view of these damages Epichoristodes acerbella presents a serious threat, especially in those areas where it can survive and multiply outdoors. Epichoristodes acerbella has been found on cut carnations imported from Italy and Cote d'Azur (Southern France) into the Federal Republic of Germany. Epichoristodes acerbella has also been intercepted in imported carnations in Britain and Norway. Between 1968 and 1986 this species was found in carnation flowers imported to the Netherlands from Kenya, Italy and Spain; it is considered a potential danger to the Dutch floricultural industry. The host plant may influence larval behaviour, because on Chrysanthemum the larvae feed only on the leaves and never mine the stems (Van de Vrie, 1991).
On apple and pear, larvae feed on foliage and on the surface of the fruit, especially in the calyx areas and where fruits touch another or where leaves have been webbed by the larvae to the cheeks of the fruits.
Distribution:
Epichoristodes acerbella originates from South Africa. It has also been recorded from Madagascar and Kenya. It has been introduced to, and is now firmly established in Italy, Spain and France on cultivated and wild plants. It also has been recorded from glasshouses in Denmark and Norway but is not established there. It has been intercepted in imported carnations in England, Germany and the Netherlands but has not been recorded from glasshouses or from plants in the open in these countries (Van de Vrie, 1991).
Pheromone:
Z 11-14Ac : 64
Z 9-14Ac : 8
Z 11-14OH : 26
Z 9-14OH
(Lalanne-Cassou and Frérot, 1980)
Parasitoids:
of egg:
Trichogramma evanescens (Westwood) (Trichogrammatidae)
of larva:
Itoplectis maculator (Fabricius) (Ichneumonidae).
Colpoclypeus florus (Walker) (Eulophidae)
Habrobracon hebetor (Say) (Braconidae)
Habrobracon nigricans Szépligéti (Braconidae)
Apanteles xanthostigmas (Haliday) (Braconidae)
Actia pilipennis (Fallén) (Tachinidae)
Nemorilla maculosa (Meigen) (Tachinidae)
of pupa:
Itoplectis spp. (Ichneumonidae)