Banana scab moth
Bruno Pinese, & Rod Elder,
Department of Primary Indudtries and Fisheries
Adapted from; Pinese, B. and Piper, R. (1994) Bananas: Insect and mite management.
Description
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Adult
The moth is small (25 mm wingspan) tan to light brown with small black spots on the wings.
Immature stages
The flattened eggs are laid in clusters ranging from a few to 30 eggs. The eggs resemble shiny overlapping fish scales. The yellow to orange larvae grow to about 25 mm before pupating.
Life history
Eggs are laid on or near to emerging bunch and hatch after about 4 days. The young larvae move under the tightly closed bracts where they feed on the young fruit. Larval development consists of five instars and is completed in an average of 14 days. As the bracts and hands progressively lift from the bunch stalk during bunch development, larvae move progressively to the next closed distal hand. Development is usually completed under the bracts which remain attached to the distal male flower bud or ' bell' . The pupal period last 8-10 days and is completed on the bunch or in trash or in old leaf axils on the pseudostem.
The complete life cycle egg to egg is completed in 28 days under hot wet conditions in tropical north Queensland. Adults are short-lived (4-5 days) and have crepuscular habits. Mating and egg laying takes place in the early evening. Adult moths hide in trash and under old leaf axils during the day.
Distribution
Found only in North Queensland north of Ingham.
Host range
Pandanus and heliconia are known alternate hosts for scab moth.
Management
Importance
Major and frequent. Occurs in northern Queensland north of Ingham.
Damage
Larval feeding causes superficial scarring on the young fruit. Damaged areas form a black callous, rendering the fruit unmarketable. Feeding is generally confined to the curve of the fruit adjacent to the bunch stalk and between the fingers. Damage ceases after the hand lifts. Mature larvae can be found under the bracts enclosing the male flower or 'bell'. It is most active during the hot wet summer months but sudden outbreaks can occur throughout the year in some localities. Damage occurs progressively as the hands lift and increases in severity towards the lower hands.
Action level
This pest is very damaging and to protect all emerging bunches, treatments must be initiated when activity is first noticed. A decision on action should be made depending on the expected bunching rate and weather conditions, rather than on scab moth populations which are difficult to predict from monitoring alone.
Control methods
Cultural
Careful selection of following suckers of equal size will ensure a concentrated bunching cycle that streamlines control.
Biological
A range of spiders and other general predators exert a measure of natural control.
Chemical
To promote biological control of scab moth and other pests, bunch injection is recommended and should be used in preference to aerial or bunch spraying. To be effective, injection must be carried out when the bunch is still upright in the throat of the plant. 20 to 40 ml of dilute insecticide solution is injected approximately a third of the way down from the top of the upright bunch or 'spear'. Injections below this will damage fruit and if done above this area, the dense 'bell' will prevent entry of the chemical.
Recommended chemicals
Chlorpyrifos, bifenthrin, acephate, bendiocarb. Check method of application. Note: This information was correct at the time of publication. However, it is the user's responsibility to ensure that registered agricultural chemicals are used in accordance with legal requirements. (See Further information). Always read the label.
Further information
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Infopest CD-ROM contains current national information on registered agricultural chemicals and is available from Infopest, DPI&F, GPO Box 46, Brisbane, Qld. 4001 or by email from infopest@dpi.qld.gov.au
- Pinese, B., Dickinson, G. and Walduck, J. 1989, Banana growers enthusiastic about bunch injections, Queensland Fruit and Vegetable News, Technical Feature, April 20, 15-17.
- Pinese, B. and Piper, R. (1994) Bananas: Insect and mite management. Department of Primary Industries, Brisbane.
- Agrilink Tropical Banana Information Kit provides information on all aspects of growing and marketing tropical bananas in Queensland. It is available from the Agrilink website or office (phone 1800 677 640) or the DPI&F Shop On-line.
- DPI&F Business Information Centre on 13 25 23 - local call 8 am to 6 pm Monday to Friday (non-Queensland residents phone 07 3404 6999). E-mail: callweb@dpi.qld.gov.au
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The DPI&F Client Service Centre at South Johnstone also holds a collection of books and papers on banana production. Call the South Johnstone Centre on 07 4064 1130
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries, Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
Last updated 04 Febraury 2004
