Suitability of hemp seed for reproduction of stored-product insects

Hemp, or industrial hemp, is a high value alternative crop that has seen major increases in acreage in Canada since commercial production was legalized in 1998. Insect infestation of stored hemp seed may result in loss of quality and value. Few published studies exist of which insect species can survive and reproduce on hemp seed. Reproduction of 10 stored-product insects on hemp seed at different moisture contents with, or without dockage, was studied. Twenty  adults were introduced into 15 g of hemp seed at two moisture contents (~8% or ~15%), two dockage levels (~0% or ~15%), and held at 30^oC and 60-70% relative humidity. Live and dead insects were counted at 3, 5, 7 and 9 weeks. After counting, only live adults were returned to the hemp seed. The population of the following species increased over the 9 weeks; red flour beetle [Tribolium castaneum (Herbst)], cigarette beetle [Stegobium paniceum (Linnaeus) ], sawtoothed grain beetle [Oryzaephilus surinamensis (Linnaeus) ], and warehouse beetle (Trogoderma variabile Ballion). The following species did not increase their populations: rusty grain beetle [Cryptolestes ferrugineus (Stephens) ], lesser grain borer [Rhyzopertha dominica (F.) ], rice weevil [Sitophilus oryzae (L.) ], flour mill beetle (Cryptolestes turcicus (Grouvelle), confused flour beetle (Tribolium confusum Jacquelin du Val), and drugstore beetle [Lasioderma serricorne (Fabricius) ]. In general, higher dockage led to higher populations. The effect of moisture content was variable.