Notes on the Sweet Potato Pyralid Moth, Megastes grandalis, Guen

Extract

Megastes grandalis was first reported from Brazil ; there have been no other records until 1919, when it was reported from Trinidad as a serious pest during certain seasons of the year to the roots and tubers of the sweet potato. At present this is the only known food-plant.

The eggs are laid two or three together in the axils of the leaf-petioles or on the underside of the leaf. The laxva at first feeds near the place where it hatches, then travels to the base of the stem and bores its way in, eating out tunnels through the roots and tubers, leaving the cortex untouched. It pupates in a silken cocoon near the surface. The moths live only a few days during which oviposition takes place. Descriptions of the immature stages are given. The writer obtained a Trichogramma egg parasite and Tachinid larval parasites.

This work was undertaken at the Imperial College of Tropical Agriculture, Trinidad, West Indies.

The Imperial Bureau of Entomology kindly identified the parasites.