Author: (Snellen, 1890)
Grey borer of sugar cane
Species Overview:
Adult: 14-18 mm wingspan (males slightly smaller than females); ground colour of forewing leaden grey, with more or less conspicuous yellowish brown streaks; basal field darker, with black strigulae; centre of wing with black marking resembling the Greek letter Upsilon; ocellus with some fine black lines; subterminal fascia arising above middle of termen, enclosing a brownish apex with a black dash, and with short black, pale edged striae at costa.
Egg: light greenish or greyish, translucent; 1.25 x 0.80 mm, elliptical; deposited singly or in pairs, on the leaf sheaths at the base of very young shoots.
Larva: 20 mm long; head yellowish brown to reddish brown or dark brown, with a small blackish streak near ocelli; thoracic shield slightly paler than head; body greyish yellow, more reddish brown dorsally; anal shield brownish yellow [Tetramoera schistaceana larva].
Pupa: 8.5-13 mm long; brownish yellow, more reddish brown dorsally; in a cocoon which blocks the opening in the stem [Tetramoera schistaceana pupa].
Taxonomic Description:
Male:
Tetramoera schistaceana adult
Tetramoera schistaceana adults
External characters: 14-16 mm wingspan; forewing without costal fold; termen sinuate; head, thorax and ground colour of forewing leaden grey, with more or less conspicuous yellowish brown streaks; basal field darker, with black strigulae; centre of wing with a black marking resembling the Greek letter Upsilon; ocellus with some fine black lines; subterminal fascia arising above middle of termen, enclosing a brownish apex with a black dash, and with short black, pale edged striae at costa. Cilia dark grey. Hindwing grey, cilia paler with dark subbasal line (Snellen, 1891).
male genitalia T. schistaceana
Genitalia: Tegumen slender and elongate; uncus band-like, curved, crowned with two long, divergent pencils of hairs. Vinculum depressed. Valva deeply cleft into an oval and hairy sacculus and a more or less hooked and ventro-laterally dilated, rather rigid cucullus. Aedeagus large, gradually attenuated. Cornutus, a long spine.
Female:
External characters: Slightly bigger than male: wingspan 18 mm.
female gen. T. schistaceana
Genitalia: Sterigma little modified, lamella antevaginalis being a slender crescentic sclerite and lamella postvaginalis a weak and broad transverse band, rounded at the sides and broadly excised in middle of lower edge. Ductus bursae rather long, gradually dilated. Corpus bursae ovoid, with a finely punctulate wall; only one signum present, with well-defined edges and a small, central, hollow spine.
Biology
Oviposition occurs on the leaf sheaths at the base of the young shoots. Eggs are deposited singly or in pairs, they hatch after 5-6 days. Larvae make irregular short tunnels upwards in the stem of the host plant, mostly near the stem surface, especially in young sugar cane. A distorted shoot, enveloped by a dry leaf, or the death of the meristem can result. They also attack the leaves of very young shoots, while in older sugar cane the tops and the older nodes of the stem are damaged. Sometimes, a transverse tunnel is formed which causes the stem to break off.
The larva can migrate from one shoot to another. Before pupation it bores through the leaf sheath (except the outer one) and makes a cocoon which blocks the opening. Pupation lasts about ten days. After the moth has hatched the empty pupal case protrudes from the stem.
Infestation of the young plants probably originates from attacks on neighbouring older cane plantations (Kalshoven, 1981; Deventer van, 1906).
Host plants:
Sugar cane (Saccharum dulce).
Damage:
The larvae make irregular short tunnels in the stem, usually near the surface and preferably in young sugar cane. The result may be a distorted shoot, enveloped by a dry leaf, and sometimes also death of the meristem. Leaves of very young shoots may also be attacked, while in older canes the tops and older nodes may be damaged. Transverse tunnels may cause the stem to break off.
According to Robinson et al., 1994, the species has seldom been reported in SE Asia during the last 10 years (Kalshoven, 1981; Geest van der et al., 1991).
Distribution:
Indoneasia (Java), China (Guangdong), Taiwan, Malaysia, the Philippines, Mauritius, Hawaii, Madagascar, Réunion (Robinson et al., 1994).
Pheromone:
Z 9-12Ac : 100
E 9,11-12Ac : 1
(Kinjo and Nagamine, 1996)
Parasitoids:
of egg:
Trichogramma sp. (Trichogrammatidae)
(reports from Indonesia mention 80% parasitization)