Journal of Economic Entomology (2010) 103, 197-202

Christos G. Athanassiou, Frank H. Arthur and James E. Throne (2010)
Effects of short exposures to spinosad-treated wheat or maize on four stored-grain insects
Journal of Economic Entomology 103 (1), 197-202
Abstract: The effect of short exposures to spinosad-treated wheat, Triticum aestivum L., or maize, Zea mays L., was evaluated against adults of four stored-product insect species: lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae); rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae); red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae); and the psocid Lepinotus reticulatus (Enderlein) (Psocoptera: Trogiidae). Adult mortality of these species was recorded after 0, 2, 4, 8, 16, and 40 h on commodities treated with 1 ppm of spinosad (immediate mortality). Then, the surviving individuals were removed and placed on untreated wheat or maize, and mortality was recorded again 7 d later (delayed mortality). Progeny production then was determined 65 and 35 d later for the beetles and psocids, respectively. Among the four species tested, R. dominica was the most susceptible, and immediate mortality after 40 h reached 78 and 72% on wheat and maize, respectively. Moreover, 7 d later, all adults that had been exposed for >2 h were dead on both commodities. Progeny production was significantly reduced in comparison with the controls, and no progeny were found when parental adults had been exposed for >8 or >4 h on wheat and maize, respectively. For S. oryzae, 40-h exposures significantly increased delayed mortality on both wheat and maize, but progeny production still was high. Generally, no effect of short exposures was noted for T. castaneum. For L. reticulatus, despite the fact that the increase of exposure interval increased mortality on maize, progeny production was not avoided. With the exception of T. castaneum, more progeny were found on wheat than on maize. The results of the current study indicate that R. dominica is very susceptible after short exposures to spinosad-treated substrate, but the other species are able to survive and reproduce at the exposure range examined.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): James E. Throne, Frank H. Arthur

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tribolium castaneum	Stored grain
	Sitophilus oryzae	Stored grain
	Rhyzopertha dominica	Stored grain
	Lepinotus reticulatus	Stored grain