Larvae of Aletia oxygala luteopallens (Sm.) found on chicory (Cichorium intybus L.) in Quebec City in May, 1958, were infested with a nuclear polyhedrosis virus and with a microsporidian. Larvae suffering from polyhedrosis leave the interior of the stems, die, and remain hanging in a characteristic way “glued” to the exterior of stems. The diagnosis of the polyhedrosis virus was confirmed by Dr. G. H. Bergold at the Insect Pathology Research Institute at Sault Ste. Marie, Ontario, and that of the microsporidian by Dr. H. M. Thomson of the same Institute. Neither microorganism had ever been noticed before.