PestFacts 6 October 2023

Cotton tipworm found on wheat

Cotton tipworm moth (Crucisoema plebejana) has been reported at Booleroo Centre feeding inside wheat grain. The caterpillars also produced some webbing, especially when disturbed.

Identifying cotton tipworm

Cotton tipworm caterpillars are 5 millimetres to 12 millimetres long, and cream in colour (sometimes tinged pink) with a dark brown head. Newly-hatched cotton tipworm can be mixed up with newly-hatched Helicoverpa caterpillars. The adult cotton tipworm moth is a marbled pale brown and white.

They are a cosmopolitan species, typically found in tropical and subtropical areas but have been recorded across Australia.

Cotton tipworm ecology

Cotton tipworm caterpillars generally feed on the immature seed capsules of Malvaceae plants and can be a cotton pest in Queensland. Outbreaks in cotton are usually associated with growth of the main host marshmallow (Malva parviflora). As the marshmallow dies off, cotton tipworms move onto cotton. They have rarely been reported feeding on wheat but there is one such record in the Waite Insect and Nematode Collection (WINC) from Gladstone in 1983. It was also reported in PestFacts November 2021. This suggests it is a very infrequent issue, but the moths may be surviving on marshmallow and moving into crops when marshmallow is controlled in the paddock.

If you observe any similar feeding damage and caterpillars, please report it to PestFacts SA to help us understand cotton tipworm occurrences. Please include the location, crop type, any nearby weeds including marshmallow and a photo in your report if possible.

Report to PestFacts

The PestFacts SA team always wants to know what invertebrates you find in your crops and pastures, whether it is a pest, beneficial or unknown – even the usual pests.

Please send your reports or identification requests via the PestFacts map.

Alternatively, please contact:

Rebecca Hamdorf
Phone: 0429 547 413
Email: rebecca.hamdorf@sa.gov.au

Maarten van Helden:
Phone: 0481 544 429
Email: maarten.vanhelden@sa.gov.au