Sugarcane bud moth
|Description of adult|
The adult is a small (10 mm long and 2 mm wide) brightly coloured moth with elongate bright yellow antennae. The forewings are bright yellow with purple-brown elongate blotches at the front and rear margins. Wingspan is approximately 15 mm. The hind wings are pale-yellow and feathery. During the day, adults rest with wings folded on banana leaves, leaf petioles and fruit but because of their small size they are seldom seen.
Eggs have not been found but are believed to be laid on the bunches and to be extremely small. The pinkish-yellow to dark grey larvae are seldom seen since they feed in secluded areas in the bunch covered by the fruit fingers. Larvae moult a number of times and when fully grown are approximately 16 mm long. A tough silken cocoon covers the light-brown pupa that the larva spins. It is completely hidden under black pellets of excreta. The silken cocoon is attached to the banana fruit usually between the fingers near feeding sites.
Length of life cycle is not known, during the summer months it is expected to take about a month.
Sugarcane bud moth has been recorded damaging bananas in Queensland, northern New South Wales and at Kununurra and Carnarvon in Western Australia. Damage appears more severe during the period December to March.
Bananas, sugarcane and possibly ornamentals such as Strelitzia are hosts.
Larvae commence feeding on the surface of fruit after the bracts have fallen. Larval feeding causes superficial scarring of fruit. Damage is less severe than from scab moth and is usually concentrated on the outside tip of fingers where contact occurs between the lower hands and those hands immediately above. It should not be confused with scab moth damage that is usually confined to areas between touching fruit and on the outer fruit curve near the bunch stalk. Sugarcane bud moth attacks old bunches and not young bunches as is the case with scab moth.
Examine 100 bunches with half-filled fruit and treat with insecticide if 5% of these have evidence of infestation. Dust all new bunches at the bagging stage, if monitoring on older bunches shows damage in excess of the action level. The time of year and the incidence of sugarcane bud moth during the previous seasons will influence the decision to treat or not.
Be aware that bananas planted close to sugarcane may suffer a higher incidence of sugarcane bud moth.
General predators such as spiders contribute to control. Parasitism is very low and is not expected to influence populations.
Dust with chemical at the time the bunch cover is applied. Minimise dust deposits on fruit by aiming the dust delivery tube towards the inside of the plastic bag. One light dusting is adequate for control. Avoid further dusting closer to harvest because it may result in a higher than permitted residue on fruit.
Chemical registrations and permits
Check the Australian Pesticides & Veterinary Medicines Authority chemical database and permit database for chemicals registered or approved under permit to treat this pest on the target crop in your State/location. Always read the label. Always observe withholding periods.