Juniperus oxycedrus subsp. macrocarpa (Sibth, & SM.) Neirl (Cupressaceae): a promising resources for integrated post-harvest crop insect pests management

Juniperus oxycedrus subsp. macrocarpa (Sibth. & Sm.) Neirl (Cupressaceae) is a dioecious evergreen shrub species, native of the Mediterranean region whose extracts, from different parts of the plant, have been used since ancient times for fragrance, flavoring, medicinal, antibacterial, insecticidal, and cosmetic purposes (1). J. oxycedrus subsp. macrocarpa is distributed from southwestern Spain to Middle East coasts (2). In Italy it is present almost in the entire peninsula including islands where it is characteristic of the consolidated coastal dunes (Habitat 2250*: Coastal dunes with Juniperus spp.). The rust-red grain beetle, Cryptolestes ferrugineus (Steph.) (Coleoptera Laemophloeidae), is the smallest of the grain beetles (1.5-2 mm), reddish-brown, flat and slender in the in the appearance. It is a worldwidediffused secondary pest that attacks grains, grain products and a multitude of dried vegetables and fruits. Sitophilus oryzae (L.) (Coleoptera Curculionidae) also called lesser rice weevil, is a small (2.5 - 4 mm), dark brown species with 4 distinct reddish patches on the elytra. S. oryzae is one of the most important pests of grains, pasta, flour, legumes, baked goods and even tobacco (3). Both species are therefore considered among the most harmful to the stored food causing huge losses wordwide. For these reasons, eco-friendly strategies to prevent such insect attacks to the stored and/or final packaged products are therefore highly foreseen. Due to their repellent properties, essential oils, obtained from aromatic plants, could represent a valid, ecofriendly alternative to synthetic repellents. In this study, the J. oxicedrus subsp. macrocarpa essential oil (JEO) was prepared from leaves and seed cones collected, from individuals growing along the Northern coast of Tuscany (Italy) in the Migliarino, San Rossore, Massaciuccoli Natural Park. JEO chemical composition was assessed by gas chromatography (GC) and by gas chromatography/electron impact mass spectroscopy (GC-EIMS). The repellent activity of JEO, against C. ferrugineus and S. oryzae, was then evaluated, in vitro, by the Area Preference Method (4). The results showed that JEO is constituted mainly by mono and sesqui-terpene hydrocarbons and that is rich in chemical components such as α-pinene that has been shown to be very effective as repellents against stored food insect pests (4). Area preference bioassay indicated that JEO exerts a good repellency against S. oryzae and C. ferrugineus. Interestingly, according to probit analysis, C. ferrugineus is about 15 times more susceptible to JEO than S. oryzae. Since aromatic plants EOs present very low toxicity to mammalians and no significant risks to the environment, JEO could represents an interesting, sustainable alternative to synthetic insects repellents that could contribute to fight the losses caused to stored food by insect pests.