Cryptolestes pusilloides (Steel and Howe 1952) may have originated in Australia (Howe and Lefkovitch 1957). In a survey, C. pusilloides was found on 15.8% of 60 Australian farms but not at 11 central grain storages (Sinclair and Bengston 1980). Population growth and emigration of C. pusilloides from 27.3 kg of clean wheat over 15 months were lower than that for C. pusillus and C. ferrugineus (Sinclair and Adler 1984). In Australia, traps baited with 1-octen-3-ol caught mostly C. ferrugineus, only six C. pusillus and no C. pusilloides (Stevens et al. 2019).
C. pusilloides was very rare as a storage pest prior to 1944 but as a result of international trade is now quite common on cereals and other commodities in the southern regions of the world (Halstead 1993). Long-term cereal storage coupled with disturbance in shipping routes brought about by war allowed expansion of its range (Howe and Lefkovitch 1957, Lefkovitch 1964). Since 1950, C. ferrugineus is found in cargos imported into Great Britain 2.05 times as often as C. pusillus and 3.1 times as often a C. pusilloides (Howe and Lefkovitch 1957). C. pusilloides was found in warehouses (58 times), buffer depots (26), flour mills (3) and other mills (3), farms (1) and maltings (1) in Great Britain. During the 13 years from 1957-1969 cargos from Australia, South America and South Africa with C. pusilloides were 43%, 26% and 24%, respectively of 180 cargos imported into Great Britain (Aiken 1975). All other countries were 7%. C. pusilloides requires warm moist conditions for development (Lefkovitch 1964) and further spread into East Africa is expected to extend its range (Aitken 1975). C. pusilloides prior 1957 invaded storage facilities in Brazil and prior 1953 was not found in Argentinian wheat imports into England (Howe and Lefkovitch 1957).
C. pusilloides is not cold hardy (Solomon and Adamson 1955) and is unlikely to establish outdoors in northern regions (Howe and Lefkovitch 1957 in England, Brauer 1970 in Germany). Today in Germany, C. pusilloides is known to occur both in grain and in bakeries (Scholler and Prozell 2014). Establishment in Italy (Ratti 1978) or Portugal (Aitken 1975) may be possible. C. pusilloides was imported to England from Portugal with almonds and kibbled locust bean (Steel and Howe 1952, Lefkovitch 1964, Aitken 1975). Probably introduced to Portugal from Mozambique (Halstead 2003).
Commodity Infestation Records (Hagstrum et al. 2013)
Almond, aniseed (anise spice), barley, basketware (wicker), bean, betel nut (areca nut), carob, carob meal, cashew, cereal product, coffee bean, date, grain, grain products, maize, maize cob, maize meal, mushroom-dried, oilseed, oilseed products, peanut, pepper-dried chilli pod, plum, rice, seafood-dried, seaweed-dried, sorghum (broomcorn), spice, wheat, wheat bran (pollard), wheat flour and wheat products. Commodities added to this list include buckwheat (Ratti 1978), kibbled locust bean (Steel and Howe 1952, Lefkovitch 1964), and fish-dried and sunflower seeds (Colombian Agricultural Institute (ICA) Resolución N° 2088 of August 12, 2019, https://www.analdex.org/wp-content/uploads/2019/09/Resoluci%C3%B3n-2088-Restricciones-de-la-CAN.pdf). Columbia has intercepted C. pusilloides in six shipments of green coffee beans between 07 Feb 2018 and 14 May 2019 from Peru and one on 19 Jan 2018 from Ecuador.
Geographic distribution (Hagstrum and Subramanyam 2009)
Africa: Burundi, Lesotho, Malawi, Mozambique, Rwanda, South Africa, Swaziland, Tanzania, Uganda, Zimbabwe
Asia: China, Hong Kong, Japan, Myanmar, Singapore, Sri Lanka, Thailand
Europe: Austria, England, Germany, Greece, Italy, Portugal, Russia, Spain
North America: Canada, Mexico, USA (HI, MN)
Oceania: Australia, Fiji, New Caledonia, Papua New Guinea, Samoa
South America: Argentina, Brazil, Guyana, Uruguay
Today, distribution of C. pusilloides can be considered cosmopolitan, although it is generally only established in the warmer areas (Santamaria et al. 1996). C. pusilloides was found infesting pet food in retail stores in Kansas, USA (Roesli et al. 2003) and has also been reported in Bulgaria (Obretenchev 2013), Gough Island (Gaston et al. 2003), Hungary (Merkl 2006), Maltese Islands (Halstead 2003), Oregon, USA (Bishop 1959) and several other European countries, i.e. Belgium, Croatia, Czech Republic, Denmark, Finland, France, Malta, Poland, Serbia, Sweden, Ukraine (Denux and Zagatti 2010). Freeman (1952) gave many examples of C. pusilloides and other Cryptolestes species causing grain heating. C. pusilloides has been found in greenhouses or compost heaps in Austria, Germany, Norway and Sweden (https://www.nobanis.org/species-info/?taxaId=5008).
Howe (1951), in discussing Cryptolestes spp. found in stored food premises in Great Britain, called attention to C. pusilloides (Steel and Howe 1952) that infested bulk Manitoba wheat at Birkenhead in 1945 (Lucas and Oxley 1946). Cryptolestes pusilloides (Steel and Howe 1952) formerly in genus Laemophloeus is most similar to Cryptolestes pusillus (Schonherr) (Halstead 1993). C. pusillus has been previously reported as Laemophloeus minutus Olivier. The two species have similar low rates of increase and climate requirements (Howe 1965, Sinha 1978). Davies (1949) and Williams (1954a,b) indicated that they had studied C. pusillus not C. pusilloides.
The eggs of five Cryptoletes species showed some difference in shape and size but there was considerable variability (Kucerova and Stejskal 2002). Variation in surface structure generally was insufficiently to be of value in distinguishing the species.
Hossain et al. (1986) has key to mature larvae of Cryptolestes, and Brauer (1970) and Halstead (1993) have keys to adults. Examination of the internal reproductive organs may be important for correct identification of species in pusilloides group, i.e., evansi, minimus, pusilloides, pusillus, turcicus and ugandae (Haines 1981, Lefkovitch 1962). Banks (1979) provides rapid technique for preparation of suitable mounts and key for adults of 6 Cryptolestes species. Banks (1979), Finlayson (1950) and Steel and Howe (1952) provide drawings or photographs of internal reproductive organs of C. pusilloides. Recently, molecular methods have been developed for Cryptolestes species identification (Wang et al. 2014, Varadínová et al. 2015, Tay et al. 2016, Chen 2020).
Fumigation and Insecticides
Fumigation with methyl bromide (Lefkovitch 1965) and phosphine (Abreu 1988) are effective against C. puscilloides. In Australia, strains of C. pusilloides resistant to phosphine were discovered (Tay et al. 2016). Cryptolestes pusilloides in Australia were susceptible to malathion and fenitrothion (Sinclair and Bengston 1980).
Abreu, J. M. de 1988. Avaliação de Gastoxin e Fertoxin na fumigação de cacau armazenado (Evaluation of Gastoxin and Fertoxin in the fumigation of stored cocoa). Revista Theobromia 18(3): 181-188.
Aitken, A. D. 1975. Insect travelers. Volume I. Coleoptera. A survey of the beetles recorded from imported cargoes by the insect inspectorate of the Ministry of Agriculture, Fisheries and Food with a special analysis for the years 1957 to 1969. Tech. Bull. 31. Her Majesty’s Stationary Office, London.
Banks, H. J. 1979. Identification of Stored Product Cryptolestes Spp (Coleoptera, Cucujidae) – Rapid Technique for Preparation of Suitable Mounts. Journal of the Australian Entomological Society 18: 217–22.
Bishop, Guy W. 1959. The comparative bionomics of American Cryptolestes (Coleoptera-Cucujidae) that infest stored grain. Annals of the Entomological Society of America 52(6): 657-665.
Brauer, G. 1970. Bedeutung der Leistenkopfplattkafer (Cryptolestes Ganglb.; Coleopt.; Cucujidae) fur die Vorratshaltung van Getreide und Getreideerzeugnissen (Significance of the flat beetles (Cryptolestes Ganglb .; Coleopt .; Cucujidae) for the storage of grain and grain products) Nachrichtenblatt deutschen Pfianzenschuttzdienst/ Newsletter of the German Plant Protection Service 24(11): 216-222.
Chen, Dongxu, Tao Zhang, Radek Aulicky, Vaclav Stejskal, Yonglin Ren, Yang Cao, David Hawthorne, and Zhihong Li. 2020. Real-time PCR for identification of five species of Cryptolestes based on COI barcode region. Journal of Stored Products Research 87, 101623.
Davies, R. G. 1949. The biology of Laemophloeus minutus Oliv. (Col. Cucujidae). Bulletin of Entomological Research 40(1): 63-82.
Denux, O. and Zagatti P 2010. Coleoptera families other than Cerambycidae, Curculionidae sensu lato, Chrysomelidae sensu lato and Coccinelidae. BioRisk 4(1): 315–406.
Finlayson, L. H. 1948. Host Preference of Cephalonomia waterstoni Gahan, a Bethylid Parasitoid of Laemophloeus species. Behaviour 1: 275–315.
Freeman, J. A. 1952. Laemophloeus spp. as major pests of stored grain. Plant Pathology 1(3): 69-76.
Gaston, Kevin J., Alex G. Jones, Christine Hänel, and Steven L. Chown. 2003. Rates of species introduction to a remote oceanic island. Proceedings of the Royal Society of London. Series B: Biological Sciences 270(1519): 1091-1098
Hagstrum, D. W., and Bh. Subramanyam. 2009. Stored-Product Insect Resource. AACC International, St. Paul, Minnesota.
Hagstrum, D. W., T. Z. Klejdysz, Bh. Subramanyam and J. Nawrot. 2013. Atlas of Stored-Product Insects and Mites. AACC International, St. Paul, Minnesota.
Haines, Christopher Peter. 1981. Insects and arachnids from stored products: a report on specimens received by the Tropical Stored Products Centre 1973-77. Report of the Tropical Products Institute No. L 54.
Halstead, D. G. H. 1993. Keys for the identification of beetles associated with stored products—II. Laemophloeidae, Passandridae and Silvanidae. Journal of Stored Products Research 29(2): 99-197.
Halstead, David GH, and David Mifsud. 2003. Silvanidae and Laemophloeidae (Coleoptera: Cucujoidea) from the Maltese Islands (Central Mediterranean). Central Mediterranean Naturalist, Malta 4(1): 41-46
Hossain, M., Verner, P. H. and Rezaur, R. 1986. Taxonomic descriptions of the mature larvae of six species of Cryptolestes (Coleoptera: Cucujidae). Bangladesh Journal of Zoology 14(2): 139-148
Howe, R. W. 1951. A Note on Grain Pests of the Genus Laemophloeus (Col., Cucujidae). Entomologist monthly Magazine 87: 161.
Howe, R. W. 1965. A summary of estimates of optimal and minimal conditions for population increase of some stored products insects. Journal of Stored Products Research 1(2): 177–84.
Howe, R. W. and L. P. Lefkovitch 1957. Distribution of the storage species of Cryptolestes (Col., Cucujidae). Bulletin of Entomological Research 48: 795–809.
Kucerova, Z. and Stejskal, V. 2002. Comparative egg morphology of Silvanid and Laemophloeid beetles (Coleoptera) occurring in stored products. Journal of Stored Products Research 38: 219–227.
Lefkovitch, L. P. 1962. A revision of African Laemophloeinae (Coleoptera: Cucujidae). Bulletin of the British Museum Natural History Entomology 12(4): 165-245.
Lefkovitch, L. P. 1964. Biology of Cryptolestes pusilloides (Steel & Howe) (Coleoptera, Cucujidae), a pest of stored cereals in the southern hemisphere. Bulletin of Entomological Research 54 (4): 649–656.
Lefkovitch, L. P. 1965. Differences between six species of Cryptolestes (Coleoptera, Cucujidae) in susceptibility to methyl bromide vapour. Bulletin of Entomological Research 56(1): 197-200
Lucas, C. E. and Oxley, T. A. 1946. Study of an infestation by Laemophloeus sp. (Coleoptera Cucujidae) in bulk wheat. Annals of Applied Biology 33(3): 289–293.
Merkl, O. 2006. New beetle species in the Hungarian fauna (Coleoptera). Folia Entomologica Hungarica 67: 19-36.
Obretenchev, Doncho 2013. New insects established in storage biotopes and the processing enterprises of Bulgaria. Acta Entomologica Bulgarica 19(1-2): 109-121.
Ratti, E. 1978. Risultati di alcuni controlli fitosanitari nel porto di Venezia. 2. Una infestazione da Cryptolestes pusilloides (Steel, Howe) su arachidi sgusciate importate dall’Argentina (Results of some phytosanitary controls in the port of Venice. 2. An infestation with Cryptolestes pusilloides (Steel, Howe) on shelled peanuts imported from Argentina). Bollettino Della Societa Entomologica Italiana 110 (4–5): 80–81.
Roesli, Rennie, Bhadriraju Subramanyam, James F. Campbell and Kim Kemp. 2003. Stored-product insects associated with a retail pet store chain in Kansas. Journal of Economic Entomology 96(6): 1958-1966.
Schöller, Matthias and Sabine Prozell. 2014. Stored-product insects and their natural enemies in Germany: a species-inventory. Integrated Protection of Stored Products IOBC-WPRS Bulletin 98: 27-34.
Sinclair, E. R., and M. Bengston. 1980. The frequency of Cryptolestes spp. in grain in south-east Queensland. Australian Journal of Experimental Agriculture 20(103): 234-239.
Sinclair, E.R. and J. Alder 1984. Migration of Stored-Grain Insect Pests from a Small Wheat Bulk. Australian Journal of Experimental Agriculture 24(125): 260–66.
Sinha R. N. 1975. Climate and the infestation of stored cereals by insects. p. 117-141. Proceedings of 1st International Working Conference Stored-Product Entomology, Savannah 1974.
Solomon, M. E. and B. E. Adamson 1955. Powers of survival of storage and domestic pests under winter conditions in Britain. Bulletin of Entomological Research 46(2): 311–55.
Steel, W. O. and R. W. Howe 1952. A new species of Laemophloeus (Col.: Cucujidae) associated with stored products. Proceedings of the Royal Entomological Society of London Series B, Taxonomy 21(5‐6): 86-88.
Santamaria J.M., Gayosos A. and Otero J.C., 1996. The Laemophloeidae Ganglbauer, 1899 (Coleoptera) from the Iberian Peninsula. Boletin de la Asociacion española de Entomologia, 20 (3–4): 107–114.
Stevens, M.M., Wood, R.M. and Mo, J. 2019. Monitoring flight activity of Cryptolestes ferrugineus (Coleoptera: Laemophloeidae) in outdoor environments using a commercial pheromone lure and the kairomone 1-octen-3-ol. Journal of Stored Products Research, 83: 227-235.
Tay, Wee Tek, Stephen J. Beckett, and Paul J. De Barro. 2016. Phosphine Resistance in Australian Cryptolestes Species (Coleoptera: Laemophloeidae): Perspectives from Mitochondrial DNA Cytochrome Oxidase I Analysis. Pest Management Science 72(6): 1250–59.
Varadinova, Z., Y. J. Wang, Z. KuÄerová, V. Stejskal, G. Opit, Y. Cao, F. J. Li, and Z. H. Li. 2015. COI barcode based species-specific primers for identification of five species of stored-product pests from genus Cryptolestes (Coleoptera: Laemophloeidae). Bulletin of Entomological Research 105(2): 202-209.
Wang, Y.J., Li, Z.H., Zhang, S.F., Varadínová, Z., Jiang, F., Kučerová, Z., Stejskal, V., Opit, G., Cao, Y. and Li, F.J. 2014 DNA barcoding of five common stored-product pest species of genus Cryptolestes (Coleoptera: Laemophloeidae). Bulletin of Entomological Research 104: 671–678.
Williams, Gwyneth C. 1954a. Observations on the life history of Laemophloeus minutus (Ol.)(Col. Cucujidae) when bred on various stored cereals and cereal products. Bulletin of Entomological Research 45(2): 341-350.
Williams, G. C. 1954b. Observations on the effect of exposure to a low temperature on Laemophloeus minutus (Ol.) (Col. Cucujidae). Bulletin of Entomological Research 5(2): 351–59.