The effect of the diatomaceous earth formulation DiatoSec on mortality of granary weevil Sitophilus granarius (Coleoptera: Curculionidae) in grains

• Published in: Journal of plant diseases and protection (2006) 2012-02, Vol.119 (1), p.30-33
• Main Authors: Keszthelyi, Sándor, Pál-Fám, Ferenc
• Format: Article
• Language: English
• Subjects: Barley; Beetles; Biomedical and Life Sciences; Corn; Diatomaceous earth; Dosage; Grains; Life Sciences; Mortality; Plant Pathology; Plant Physiology; Plant Sciences; Progeny production; Rice; Weevils
• ISSN: 1861-3829; 1861-3837
• DOI: 10.1007/BF03356416

The insecticidal efficacy of the diatomaceous earth formulation DiatoSec® (Ediafilt Diatomite Mining and Processing Ltd., Hungary) against the granary weevil, Sitophilus granarius (Coleoptera: Curculionidae), was evaluated on maize and barley grain in laboratory tests. The diatomaceous earth formulation was applied at three doses of 1, 2 and 4 g kg⁻¹ of both grain types. Mortality of S. granarius adults was estimated after 24 and 48 h and 7, 14 and 21 d of exposure on treated grain. After the 21 d counts, all the exposed adults were removed and progeny production on treated grains was assessed 45 days later. The insecticidal efficacy of the examined diatomaceous earth against the granary weevil was highly influenced by grain type, exposure time and dose. The longer exposure times increased weevil mortality in the case of both grains. The efficacy on maize was unsatisfactory. On the other hand, 85% of the weevils were died after a 21 d exposure on barley treated with the highest dose. In addition, progeny production on treated barley was completely suppressed. In all, a satisfactory level of protection was only achieved with barley at a rate of 4 g kg⁻¹. Differences in efficacy between grain types could be traced back to differences in grain surface. The lower efficacy — than some examined silica products — of DiatoSec as compared to similar products can be explained by the lower SiO₂ content.