Journal of Pest Science (2016) 89, 945-954

H.A. E. Malia, C.A. RosiDenadai, N.M. P. Guedes, G.F. Martins and Raul Narciso C. Guedes (2016)
Diatomaceous earth impairment of water balance in the maize weevil, Sitophilus zeamais
Journal of Pest Science 89 (4), 945-954
Abstract: As water balance is a fundamental component for insect homeostasis, inert dusts such as diatomaceous earth (DE) are physical insecticides that allegedly impair water balance causing insect death by desiccation. Death by desiccation and water loss were indeed reported when using DE against a few stored product insects at discreet relative humidities, which may vary with species, strain, and DE deposit. Here we assessed the activity of two DE formulations from distinct deposits, Insecto^® and KeepDry^®, against the maize weevil (Sitophilus zeamais), a key pest species of stored cereals in warmer climates. We tracked their action on the insect integument, and impairing water balance in a range of relative humidity, assessing their effect on insect water content and rate of water loss. Both DE formulations compromised insect survival at the full range of relative humidities tested (i.e., from 0 to 100 %) reducing in a third the median survival time. Both DE formulations damaged the insect tegument surface, including sensilla and pores, and compromised water balance reducing body water content and increasing the rate of water loss in over twofold. However, such activity and efficacy differed between DE formulations with KeepDry^® leading to greater insecticidal activity and impairment of water balance in the maize weevil than the Insecto^® formulation.
(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): Raul Narciso C. Guedes

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.
	Sitophilus zeamais