Oryzaephilus surinamensis (Linnaeus)
Taxonomic placing: Insecta, Holometabola, Coleoptera, Sylvanidae.
Common name: Sawtoothed grain beetle.
Geographical distribution: World-wide.
Morphology: The dark-brown adult is slender, about 3-4 mm in size. The prothorax bears a series of lateral teeth-like protuberances (hence the common name) and 2 longitudinal dorsal furrows. Elytra with longitudinal striae and with punctuations. Larva yellow with brown spots, length 5 mm. The antennae brown, the segments bead-like.
Life cycle: Females place their eggs (about 370-400/female) loosely upon various foodstuffs, on which the emerging larvae feed. A life cycle requires 20–80 days at 18–37°C, and several generations may overlap because adults can live for 6-10 months. They fly only in warm weather and long distance dispersal occurs when infested grains or other contaminated food products are transferred.
Economic importance: This beetle is often considered to be a secondary pest, because it does not usually attack entire seeds; cereals that were damaged by other pests may facilitate its colonization. It is a cosmopolitan invader of packaged foods.
Management
Monitoring: Usually by visual inspections, or by checking the temperature of the grain, which becomes warm. An electronic grain probe Insect counter system for monitoring this pest has been developed.
Cultural methods: Keeping the storage and production areas, as well as any packaging materials, clean and dry before storage. Using only strong packing material without any holes. Sieving in order to remove pest-containing damaged grains may limit infestations.
Physical control: Inert dusts, like ash and clay, when added to the grain, can reduce pest numbers by causing them to die from desiccation. Freezing and heating, an effective method for the control for several stored product pests, also affects the sawtoothed grain beetle.
Controlled atmosphere: Wherever closed infrastructures exist, the combination of low oxygen and carbon dioxide-enriched atmospheres can be used to control stored product pests.
Chemical control: The pest is developing resistance to many pesticides. Fumigation with phosphine, once widely applied, is now seldom used due to being poisonous. Many natural and synthetic essential oils have been used to control of this beetle.
Biological control: The bethylid Cephalonomia tarsalis (Ashmead) is a predator and parasitoid of the pest larvae, which are also very susceptible to the entomopathogenic fungus Beauveria bassiana ((Bals.-Criv.) Vuill., a registered mycoinsecticide.
References
Al-Jabr, A.M. 2006. Toxicity and repellency of seven plant essential oils to Oryzaephilus surinamensis (Coleoptera: Silvanidae) and Tribolium castaneum (Coleoptera: Tenebrioidae). Scientific Journal of King Faisal University (Basic and Applied Sciences) 7: 49-60.
Beckel, H., Lorini, I. and Lazzari, S.M.N. 2006. Resistance detection of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) to organophosphorous and pyrethroids insecticides. 9th International Working Conference on Stored Product Protection 312-318.
Epsky, N.D. and Shuman, D. 2001. Laboratory evaluation of an improved electronic grain probe insect counter. Journal of Stored Products Research 37: 187-197.
Finkelman, S., Navarro, S., Rindner, M. and Dias, R. 2006. Effect of low pressure on the survival of Trogoderma granarium Everts, Lasioderma serricorne (F.) and Oryzaephilus surinamensis (L.) at 30°C. Journal of Stored Products Research 42: 23–30.
Klys, M. 2012. Emigration activity of the saw-toothed grain beetle Oryzaephilus surinamensis L. (Coleoptera: Silvanidae) in various environmental temperatures. Journal of Plant Protection Research 52: 397-400.
Lord, J.C. 2001. Response of the wasp Cephalonomia tarsalis (Hymenoptera: Bethylidae) to Beauveria bassiana (Hyphomycetes: Moniliales) as free conidia or infection in its host, the sawtoothed grain beetle, Oryzaephilus surinamensis (Coleoptera: Silvanidae). Biological Control 21: 300–304.
Shaaya, E. Ravid, U., Paster, N., Juven, B., Zisman, U. and Pisssarev, V. 1991. Fumigant toxicity of essential oils against four major stored–product insects. Journal of Chemical Ecology 17: 499-504.
Trematerra, P., Sciarreta, A. and Tamasi, E. 2000. Behavioral responses of Oryzaephilus surinamensis, Tribolium castaneum and Tribolium confusum to naturally and artificially damaged durum wheat kernels. Entomologia Experimentalis et Applicata 94: 195-200.