Cadra cautella Walker, 1863 - Tropical Warehouse Moth

Summary

The tropical warehouse moth is found throughout the tropics and subtropics where it is more common in non-arid areas. The tropical warehouse moth feeds on a range of stored foods, notably cereals and cereal products.  The larvae (caterpillars) feed externally on maize grains but also cause damage to stored products through contamination with the silk webbing it produces and faecal pellets, cast skins and egg shells.

Common Names

Tropical warehouse moth, Mediterranean flour moth, Dried currant moth, Almond moth, Fig moth (English)

Synonyms

Cadra defectella Walker, 1864; Cryptoblabes formosella Wileman & South, 1918; Ephestia cautella (Walker, 1863); Ephestia irakella Amsel, 1959; Ephestia passulella Barrett, 1875; Ephestia pelopis Turner, 1947; Ephestia rotundatella Turati, 1930; Nephopteryx desuetella Walker, 1866; Nephopterix passulella (Barret, 1875); Pempelia cautella Walker, 1863

Taxonomic Position

Phylum: Arthropoda; Class: Hexapoda (Insecta); Order: Lepidoptera; Family: Pyralidae

Origin and Distribution

The tropical warehouse moth is found throughout the tropics and subtropics where it is more common in non-arid areas. It can be found in temperate countries but can only survive the winter in heated areas.

Description

Eggs
The eggs are translucent yellow with a sculptured surface.

Larvae
The larvae range from 1.5-15 mm in length and are light brown with dark brown spots with a sparse covering of hair.

Pupae
Pupae are dark-brown and found within a relatively light pupal case.

Adults
The adult forewings are greyish-brown with scattered darker patches. The wing span is 11-20 mm and both fore- and hind-wings have broadly rounded tips and short fringes of hairs.

Similar Species

The adult tropical warehouse moth is commonly confused with the Indian meal moth, Plodia interpunctella but can be differentiated from it by the distinct colouring of the forewings of Indian meal moth (a dark band separating the two differently coloured halves of the forewing). The larva resembles that of the Indian meal moth.

Life Cycle

The females lay their slightly sticky eggs on the stored food. Up to 300 eggs are laid in the first 3-4 days of their short (8-9 day) lives. At 30°C the eggs hatch in approximately 3 days. There are normally five larval instars and larval development, under optimum conditions (32.5°C and 70% relative humidity) is completed in about 22 days. In heavy infestations the mature larvae leave the produce to pupate on surfaces such as walls of the store or in spaces between bags. Before pupation, the last instar larva builds a cocoon. The pupal stage is completed in about 7 days. Adult emergence from the cocoon usually occurs during the late afternoon. Under optimum conditions, development from egg to adult takes 29-31 days.

Pest Destructive Stage

Larval stage (caterpillar )

Host Range

The tropical warehouse moth is a major pest of a range of stored foods, especially cereals (maize, rice, wheat, sorghum, millet, oats) flours and other cereal products, dried cassava, groundnuts, cocoa beans, dried mango, dates, nutmeg, mace, cowpeas and other dried stored products.

Host Lifestage Affected

Post-harvest and storage

Host Plant Part Affected

Fruits, pods seeds and grains

Damage Symptoms

External feeding and trails of silk webbing that contaminates stored products.

Pest Management

Detection methods
The tropical warehouse moth can be detected by visual inspection. Sticky traps baited with a sex pheromone can be used to monitor adults.

 

Cultural practices

The severity of a tropical warehouse moth infestation can be reduced by good store hygiene which includes cleaning the store between harvests, immersing grain sacks in boiling water and fumigating the store to eliminate residual infestations, ensuring that all spillages are removed, all cracks and crevices in the store are filled and the selection of only uninfested material for storage. Infestations of this species may also be limited by the storage of good quality grains such as whole cereals with fewer broken grains.

Biological pest control

The mass release of the parasite Habrobracon hebetor has been used in South Africa to control the tropical warehouse moth in a sultana store as part of an integrated pest management programme.

Controlled atmosphere
Where suitable infrastructure exists, low oxygen and carbon dioxide-enriched atmospheres can be used to control stored product pests.

 

Freezing and Heating
Where the infrastructure exists, freezing for several days and heating for 24 hours have proved to be effective control methods for stored product pests.

 

Chemical control

Fumigation of grain stocks with phosphine will control existing infestations but will not protect against re-infestation. An admixture of approved grain insecticides, especially organophosphorus compounds, will protect against this pest. Store misting or fogging at times of peak flight activity may be used to control the adult population. Pesticides are poisons so it is essential to follow all safety precautions on labels.

Sources of Information and Links

Burges HD, Haskins KPF, 1965. Life-cycle of the tropical warehouse moth, Cadra cautella (Wlk.) at controlled temperatures and humidities. Bulletin of Entomological Research, 55(4):775-789.

CABI. (2007) Ephestia cautella (Walker) Tropical warehouse moth datasheet. Crop Protection Compendium, 2007 Edition. CAB International Publishing. Wallingford, UK.

Dent D. (2000). Insect pest management.CAB International Wallingford, UK

Infonet-Biovision. http://www.infonet-biovision.org/default/ct/91/pests. Accessed on 28 Jan 2011.

Gaby, S. (1988) Natural crop protection in the tropics. Margraf Publishers Scientific books, German

Krischik, V.A., Cuperus G. and Galliart D. (eds.).(1995). Stored Products Management, 2nd Ed. Oklahoma State Univ. 204 pp. http://www.grainscanada.gc.ca/storage-entrepose/pip-irp/lgb-ppg-eng.htm#d accessed on 15/5/2010.

Ridgway, R.L. Silverstein R.M and Inscoe, M.N. (1990) Behaviour- modifying chemicals for insect management, Marcel Dekker Inc., New York.

Youdeowei A. (1993) Pest and vector management in the tropics, Longman Group Ltd England.

Editors

Anne M. Akol, Makerere University; Maneno Y. Chidege, Tropical Pesticides Research Institute; Herbert A.L. Talwana, Makerere University; John R. Mauremootoo, BioNET-INTERNATIONAL Secretariat.

Acknowledgments

We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).

Contact

BioNET-EAFRINET Regional Coordinator: eafrinet@africaonline.co.ke