Infestation of Stored Saw Palmetto Berries by Cadra Cautella (Lepidoptera: Pyralidae) and the Host Paradox in Stored-Product Insects

The almond moth, Cadra cautella (Walker), is a common storage pest known to infest a wide range of dried plant materials, and it has been recorded from a warehouse in Florida during storage of dried passion-flower (Passiflora incarnata L.) and dried saw palmetto berries Serenoa repens (Bartram) Small. Its status as a pest of stored saw palmetto was confirmed by trapping in a second warehouse used solely for storage of this commodity. The moth occurred in high numbers, captures were closely associated with stacks of bagged berries, and trap catch was very low after the stacks were consolidated under a tarp and fumigated. Yet the results of laboratory rearing on saw palmetto suggested that C. cautella has little ability to infest this commodity--development was protracted and highly variable in duration, mortality was high, and pupal weight was low. This sort of contradiction in host suitability, which we refer to as the “host paradox,” may be widespread among stored-product insects but has seldom been reported and almost never studied. Published reports suggest that the solution lies partly in dietary supplementation through fungivorous, saprophagous, or carnivorous feeding, although more subtle factors also are suggested. Even cursory observations of the host paradox should be reported to document frequency of occurrence and perhaps stimulate studies directed toward solutions. Such studies would inevitably provide better understanding of population dynamics, which would, in turn, lend support to better management of insects in commercial storage situations.