NC State Extension Publications

Biology

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Not much is known about the life history of the spotted fireworm, Choristoneura parallela, in North Carolina. The closely related obliquebanded leafroller has two generations per year. Since spotted fireworm moths have been collected from April until October, it is likely they also have at least two generations per year. Obliquebanded leafrollers are noteworthy because they overwinter as tiny caterpillars in a very small cocoon on the bark. This kind of cocoon is called a hibernaculum. These caterpillars emerge in the spring and feed on the tender new growth. Spotted fireworms are also leafrollers, that is, they roll the leaves up and reside within when not feeding. At maturity, the caterpillars pupate within the rolled up leaf. Sometime afterward new moths emerge. Female moths secrete a pheromone that helps males find them. After mating, females lay eggs on various kinds of trees, shrubs and flowers.

A spotted fireworm on azalea

A spotted fireworm on azalea exposed by opening its leaf roll.

Spotted fireworm moth

Spotted fireworm moths are about 3/8 inch long.

Pupal skin of the spotted fireworm

Spotted forworms pupate inside the rolled leaves.

Host Plants

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Spotted fireworms infested a large number of ornamental plants where they roll up leaves from which they emerge to feed on nearby foliage. Spotted fireworms have been collected from almond, azalea, blueberries, citrus, cranberry, gardenia, goldenrod, roses, and sheep laurel.

Residential Recommendation

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It is difficult to get an insecticide into the rolled up leaves to kill the worms. However, spotted fireworms are not reputed to be resistant to insecticides, so infested plants can be treated with pyrethroids to control the spotted fireworms as they come out of their leaf rolls to feed. When used as directed, pyrethroids are very toxic to insects but are not particularly hazardous to humans and pets (other than fish-avoid using pyrethroids around pools, ponds, and streams).

Author

Professor Emeritus
Entomology and Plant Pathology

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Publication date: July 2, 2013
Revised: Oct. 15, 2019

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