Sunflower Moth

species: homeosoma electellum
common names: sunflower moth
hosts: sunflower
notes:

Agriculture and Agri-Food Canada Insect Identification Sheet No. 95 1986 Sunflower Moth Homeosoma electellum (Hulst) The sunflower moth, the most damaging insect pest of cultivated sunflowers in North America, is widely distributed throughout Canada, the U.S., Mexico and Cuba.

Injury:

The moth deposits eggs only in pollinating blooms. The newly hatched larva feeds on pollen and flower parts during its first week; it can destroy up to 100 florets during this period. Once its feeding period ends, it tunnels its way deep into the sunflower's head and lives within a silken tube, which retains black pellets of frass.

A heavily infested sunflower head has a dark appearance. More than 400 larvae have been found in one head. In addition to cultivated sunflowers, the pest also attacks wild sunflowers and garden composites such as cosmos, zinnias, daisies and chrysanthemums.

Life History:

The adult is light grey with a wing span of about 20 mm. Its pearl-white eggs are deposited singly or in small groups among the florets. These hatch within 2 or 3 days into purplish or reddish-brown larvae characterized by four longitudinal bluish-green stripes along the back. The larval stage lasts approximately 25 days; at maturity it is approximately 20 mm long. The larva then migrates from the sunflower head by lowering itself on a silken thread to the soil, into into which it penetrates 75-100 mm.

The pupal stage lasts about 20 days; the pupa consists of a tough, silken cocoon covered with soil particles and is approximately 10 mm long. At the end of this stage, the adult moth emerges from the cocoon through a silken tube leading to the soil surface.

Unlike those in the south, only one generation of sunflower moth appears in Canada each year. Moths that fly in from the south in late June and July lay their eggs in cultivated sunflowers. These eventually become adults that emerge in late August or early September. They are usually killed off by the first frosts.

Control:

To be effective, insecticides must be applied before the young larvae tunnel their way into the sunflower head. Use synthetic pheromone bait traps to monitor sunflower moth populations. Apply insecticides only if moths are abundant. For further control recommendations consult your provincial Department of Agriculture.