Natural versus synthetic zeolites for controlling the maize weevil (Sitophilus zeamais)–like Messi versus Ronaldo?

Abstract

Laboratory experiments were carried out to evaluate the impact of zeolites of different origins on the mortality of the maize weevil (Sitophilus zeamais Motschulsky). We tested the efficacy of natural zeolites (Slovenian and Serbian) and a synthetic zeolite (Asorbio®). Diatomaceous earth (SilicoSec®) was used as a positive control. We applied the zeolites as surface treatments (at concentrations of 10 g/m2 and 20 g/m2) and as admixtures (grain with zeolites) (at concentrations of 450 ppm and 900 ppm). The mortality of the weevils when the zeolites were applied as a surface treatment was evaluated every day until the 7th day after application; delayed mortality was measured every day until the 14th day after application. When the zeolites were admixed, we evaluated mortality after the 7, 14, and 21 days. The research was performed at two different relative humidity values (55 and 75%) and at three different temperatures (15, 20 and 25 °C). We conclude that the mortality of maize weevils was influenced by relatively high temperature and low relative humidity values. There was no impact of the zeolite dose on the mortality of the maize weevils when applied as a surface treatment. The mortality of the weevils was similar in the treatments with the two natural zeolites (Slovenian and Serbian), while the mortality of the maize weevils was the lowest in the treatments with Asorbio®. The use of natural zeolites as a protectant for stored products was shown to be effective in our research, although additional surveys should be conducted.