Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 13, 2005
Publication Date: September 2, 2005
Citation: Arbogast, R.T., Chini, S.R., Kendra, P.E. 2005. Infestation of stored saw palmetto berries by Cadra Cautella (Lepidoptera: Pyralidae) and the host paradox in stored-product insects. Florida Entomologist. 88(3):314-320. Interpretive Summary: The Indianmeal moth, Plodia interpunctella (Hübner), and the almond moth, Cadra cautella (Walker), feed on an array of dried plant materials, including medicinal plants (botanicals). Observations of moth populations in a botanicals warehouse that contained either dried saw palmetto berries or chopped passion-flower vines, depending on the season, indicated that both species are capable of infesting these materials. Saw palmetto, however, appeared to be a better host for both species than passion vine, and both botanicals appeared to be better hosts for C. cautella than for P. interpunctella. The purpose of the present study was to estimate the degree of host suitability by comparing development of each species on saw palmetto, passion vine, and a standard laboratory diet. The moths were reared individually from egg hatch to adult eclosion at 27 ± 1° C and 60 ± 5% RH. Neither species completed development on passion vine. The developmental period of C. cautella on saw palmetto was longer than on laboratory diet, and pupal weight was lower. Only one P. interpunctella completed development on saw palmetto, and survival on saw palmetto was significantly lower than on laboratory diet in both species. However, we cannot conclude on the basis of these results that saw palmetto and passion vine are unsatisfactory or marginal hosts for these moths in commercial storages. Our warehouse observations provide compelling evidence to the contrary. We can only speculate that some essential factor or condition occurring in commercial storages was not provided in the laboratory.
Technical Abstract: Botanicals are dried parts of medicinal plants that are processed and refined to create a wide variety herbal products, such as nutritional supplements, herbal tea, and herbal soaps. The popularity and use of these products has grown substantially in recent years, and the economic value of the botanicals used annually in their production is estimated conservatively at $300-500 million. Harvested botanicals are dried and stored for various periods of time before processing, and during storage they are subject to damage and contamination by stored-product insects and mites. ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, have identified some of the major pest problems facing the industry and are seeking new means of managing the problems. They have found that the Indianmeal moth and the almond moth (two common pests of stored saw palmetto, passion vine, and other botanicals) developed poorly or not at all on saw palmetto and passion vine in the laboratory. This suggests that some essential factor or condition occurring in commercial storages was not present in the laboratory tests. Identification of this factor or condition could suggest ways to render the warehouse environment less suitable for pest infestation. This would reduce the need for insecticide application and would be useful to the botanicals and herbal products industry and to pest control operators.