CECROPIA MOTH
(Lepidoptera: Saturniidae)

The cecropia moth, Hyalophora cecropia, is the largest of the giant silkworm moths native to Ontario, having a wing spread of 10 to 15.5 cm. The wings are reddish-brown, and crossed in the middle with a white band. In the middle of each wing there is a crescent-shaped white spot bordered with red.

The cecropia larva (caterpillar) reaches a length of 10 cm. It has two rows of blue tubercles (protuberances) along each side, two rows of yellow tubercles down its back, and two pairs of large red tubercles on the thorax. This caterpillar feeds on the leaves of a wide variety of broad-leaved trees and shrubs. Although each caterpillar has a large appetite, caterpillars are seldom present in sufficient numbers to cause economic damage. Therefore control measures are seldom warranted.

The larva completes its growth about August and then spins a large cocoon. These cocoons are often found in tall grasses or low shrubbery and tend to have twigs and grasses incorporated into them. They are tan in colour and about 10 cm long. Winter is spent in the cocoon, and after pupation, an adult moth emerges the following May or June. After mating, the moth lays eggs on the leaves of trees and shrubs to start the cycle over again.

If you are interested in watching the development of the cecropia moth, place a caterpillar in a box or cage in August. Feed it leaves until it starts to spin a cocoon. Then keep it outside during the winter. This cocoon should be placed outside in a sheltered location for the winter, as a cold treatment is necessary for the proper development of the insect. Adult moths should emerge in May or June. As large larvae are often parasitized, parasitic wasps may emerge from the cocoon instead of an adult moth. Parasites and predators are a natural means of controlling the population. Larvae feeding on valuable ornamentals can be controlled by removing them by hand.

W.A. Attwater/M.D. Dykstra

PDCF-097 (Revised 00/06/20)