Author: (Amsel, 1960)
Nut fruit tortrix
Species Overview:
Adult: ca. 20 mm wingspan; forewing greyish white, strigulated and suffused with brownish, especially in apical third; basal patch ill-defined; band of ground colour between basal patch and ocellus broad; ocellus usually without internal markings; terminal part of wing with a conspicuous blackish pre-tornal marking, extending around ocellus to subapical area. Hindwing pale greyish-brown.
Larva: (last instar) ca. 17 mm long; head yellowish-brown; prothoracic and anal plates pale yellowish brown, with darker spots along the caudal margin of the former and on the caudal half of the latter. Body creamy white, even when fully grown never reddish; pinacula slightly darker than body.
Taxonomic Description:
Male:
C. kurokoi male
External characters: ca. 20 mm wingspan; forewing ground colour greyish white, strigulated and suffused with brownish, more so in apical third; costa strigulated with black-brown, most strongly in apical half, the interspaces white; basal patch ill-defined, angulated medially; a blackish fascia present basad to ocellus; ocellus large, usually without internal markings; terminal part of wing with a conspicuous blackish pre-tornal marking, extending around ocellus to subapical area. Hindwing pale greyish-brown (Komai and Ishikawa, 1987; Amsel, 1960).
male genitalia C. kurokoi
Genitalia: Aedeagus rather straight, tapering apically, without cornuti. Valva elongate, with small notch in ventral margin; neck of valva with sclerotized ridge; cucullus semi-elliptical. Tegumen rather slender, covered with blackish-brown (easily removed) scales.
Female:
External characters: Similar to male
female gen. Cydia kurokoi
Genitalia: 7th abdominal sternite semi-circular, shallowly concave caudally. Sterigma composed of an elliptical anterior, and a trapezoidal posterior plate (not connected). Antrum flattened, continued to cingulum. Corpus bursae with two thorn-like signa.
Setae on papillae analis straight.
Biology:
Cydia kurokoi is an univoltine species. Moths fly in August and September. Larvae feed in fruits of chestnut trees. When mature, they crawl out of the injured fruits and make hibernacula in the layer of fallen leaves on the ground, overwintering there in the larval stage (Komai and Ishikawa, 1987).
Host plants:
Castanea seguinii, Castanea mollitissima, Castanea crenata, Quercus acutissima.
Damage:
Cydia kurokoi damage
Larvae feed inside the fruits of chestnut trees and leave them damaged. The species is an important chestnut pest in warmer areas in Japan. The economic importance is small in Korea, and unknown for China.
Distribution:
Japan, Korea, Eastern China.
Pheromone:
Pheromone unknown.