Author: (Hübner, 1813)
Summer shoot moth
Species Overview:
Adult: 14-18 mm wingspan; forewing ground colour silvery white, coarsely suffused with grey and strigulated with black, with poorly defined blackish grey markings; distal area suffused with pale ochreous mixed with purplish ferruginous. Hindwing greyish fuscous.
Egg: elliptical, opaque, cream-white becoming tinged with red. Deposited on needle pairs underneath the bud whorls in rows of 2-16.
Larva: 9 mm long; head blackish brown; prothoracic plate brown, medial sulcus distinct; abdomen waxy yellowish brown, integument finely shagreened; pinacula minute, dark brown; anal plate weakly sclerotized, yellowish brown, irregularly pigmented with dark brown; thoracic legs dark brown. Abdominal legs without small sclerotized plate, with 40-50 crochets [R. duplana simulata larva].
Pupa: head and thorax reddish brown, wings and abdomen yellowish brown, abdomen paler ventrally; anal segment with four hooked setae dorsally and four pairs of hooked setae ventrally; frons with narrow process, front of process wide, not rounded apically; occasionally with two smaller lateral processes [details pupa R. duplana ].
Spun up in the larval habitation or in an angle formed by a twig; also in the soil litter.
Taxonomic Description:
Male:
Rhyacionia duplana logaea adult
External characters: 14-18 mm wingspan. Antennae strongly biciliate. Labial palpus, head, thorax and tegula black-grey, irrorate (tips of scales) with white, frons and crown of head, thorax anteriorly and base of tegula mixed with purplish ferruginous. Forewing slender, termen oblique; ground colour silvery white, coarsely suffused with grey and strigulated with black; markings blackish grey, poorly defined; basal and sub-basal fasciae forming transverse striations; median fascia narrow, slightly sinuous and directly transverse; pre-tornal marking with a strong ochreous admixture above dorsum and developed as a fasciate band to costa; subterminal fascia and ocellus obsolete; distal area suffused with pale ochreous mixed with purplish ferruginous; cilia greyish white. Hindwing greyish fuscous; cilia paler, with a dark sub-basal line (Bradley et al., 1979).
male genitalia R. duplana
Genitalia: Uncus rudimentary; gnathos not developed. Socii rudimentary. Valva strong, with large basal excavation; cucullus with ventral lobe devoid of setose cover; sacculus terminates with a smooth rounded process. Aedeagus without spinules on walls.
Female:
External characters: Similar to male.
female genitalia R. duplana
Genitalia: Sterigma reduced, funnel-shaped; antrum slightly broadening posteriorly, weakly sclerotized. Corpus bursae with two small signa.
Variation:
Only minor variation is found in the markings and general colouration of the forewing.
Biology:
The flight period of the adults usually starts in April, in warmer areas often in March. Eggs are deposited on needle pairs underneath the bud whorls in rows of 2-16. The larvae hatch after about 3 weeks and the neonate larvae move towards the top of the extending shoot. They spin webs around the bases of the needles. Initial rasp feeding is followed by penetration into the shoot, in which 2-7, and in exceptional cases up to 40 larvae feed together. The feeding proceeds from the top of the shoot towards the basis. Larval development lasts about 3 months. Between the middle of July and August, the full-grown larvae move towards the tree trunk or into the soil litter. A grey cocoon is spun here, in which pupation takes place but occasionally it can be found in the shoots. The adults are fully developed in the late autumn; they hibernate in the pupal case (Bogenschütz, 1991).
Host plants:
Pinus sylvestris, Pinus contorta var. latifolia, Pinus thunbergii, Picea sitchensis.
Damage:
According to Bogenschütz, 1991, outbreaks of Rhyacionia duplana were until then only known from Germany and the former USSR. Damage occurs especially in 5-12 year old pine trees. Infested shoots desiccate and drop to the soil. Bush growth or even dying of the crown top may be the results of repeated strong infestations.
Distribution:
Northern and Central Europe to Eastern Russia and Japan. Also recorded from Korea, but Byun et al., 1998, have not found any specimens.
In the UK, this species is represented by the subspecies Rhyacionia duplana logaea , where it is also known as the Elgin shoot moth; in Japan the subspecies Rhyacionia duplana simulata Heinrich occurs.
Pheromone:
Pheromone unknown.
Attractantia:
E 9-12Ac (Arn, 1995-99)
Parasitoids:
Apanteles insiformis Ratz. (Braconidae)
Apanteles lineatis Keinh. (Braconidae)
Bracon indubius Szepl. (Braconidae)
Aritranis pini Momoi (Ichneumonidae)
Diadegma pini Momoi (Ichneumonidae)
Ephialtes planatus Htg. (Ichneumonidae)
Hemiteles esenbeckii Grav. (Ichneumonidae)
Lissonota buolianae Hartig (Ichneumonidae)
Lissonota transversa Bridgm. (Ichneumonidae)
Scambus vulgaris Momoi (Ichneumonidae)
Tetrastichus turionum (Eulophidae).
Phytomyptera nitidiventris Rond. (Tachinidae)
Rhyacionia piniana (Herrich-Schäffer)
R. piniana male
Another species of Rhyacionia that is found on Scots Pine (Pinus sylvestris) is
Rhyacionia piniana. It occurs in Central Europe (from France to Austria, Hungary and Poland and in western Russia).
Moths are significantly smaller than the other species of Rhyacionia (wingspan 9-11 mm). Larvae feed in buds.
male genitalia R. piniana
Male genitalia: socii curved outwards.
female genitalia R. piniana
Papillae analis broader; sterigma not conical.