Pectinophora gossypiella (Saunders) and Pectinophora scutigera (Holdaway)
The pink spotted bollworm occurs in coastal and central Queensland, and will attack cotton as well as its primary hosts (cottonwood tree – Hibiscus tiliaceus and broadleaf bottle tree – Brachychiton australis). In Australia the pink bollworm is only found in the NT and north of WA where it is a pest of cotton.
Bollgard ll is not registered to control this pest but observations in the Australian environment as well as global Monsanto data suggests that it provides excellent control1.
Identification: Larvae are up to 18mm long and are yellowish-pink with a dark brown head and rows of darker markings along the back. Moths are 12mm long, dark grey or silvery-grey and hold their wings over the body when at rest.
Lifecycle: Larvae hatch from small eggs and tunnel into large squares, flowers or bolls. Mature larvae pupate in bolls, stems or surface trash. The life cycle takes about 6 weeks, but usually only one generation of pink spotted bollworm occurs during late January-March in conventional cotton. The pink spotted bollworm does not have an overwintering diapause. However, larvae can remain alive for long periods and survive by feeding on dry cotton seed in trash. Live larvae have even been found in seed cotton in modules awaiting the gin.
Damage: Larvae bore into green bolls feeding internally and to a lesser extent into squares and flowers. This results in damaged lint due to feeding and the entry of boll-rotting fungi.
Control: Effective management of cotton cropresidues will help minimise subsequent infestation in cotton. In northern Australia growing cotton in the dry season avoids major damage from pink bollworm.
Pink Spotted Bollworm moths and larva.” (Moth - right 12mm) Photo: P. Room
Damaged lint due to Pink Spotted Bollworm feeding and the entry of boll-rotting fungi. Photo; D. Ironside