The experiment was carried out at the Laboratory of Entomology of the Department of Phytomedicine, Agricultural Engineering, Field Crops Production, Pasture and Grassland Management on Biotechnical Faculty of Ljubljana. We studied the insecticidal efficacy of four locally available inert dusts (diatomaceous earth, spruce wood ash, quartz, zeolite) and dust of the invasive plants Canadian goldenrod and Giant golderod in single and combined use against rice weevil on maize and wheat grain. The insecticidal activity of the dusts was studied in growth chambers at different temperatures (15, 20, 25 and 30 ° C) and humidities (55 and 75 %). SilicoSec was used in a positive control and pure grain in negative control. 17 treatments per cereal type and 9 replicates were performed. 30 rice weevil adults were added to each flask of grain and dust and then placed in a growth chamber. Adult beetle mortality was determined on the 7th, 14th and 21st day after the experimental setup. After 3 weeks, all beetles were removed and the treated grains were exposed to darkness for 2 months. After 2 months, the progeny of the beetles were counted. After processing the data, we found that the insecticidal efficacy of the dusts was higher on wheat than on maize grain. The products were most effective at 55 % humidity and 30 ° C on wheat and 15 ° C on maize. The highest insecticidal efficacy was in the positive control, followed by the use of wood ash and diatomaceous earth. The dust treatments that were most effective in the first part of the experiment had the lowest number of progeny. Inert and plant dusts did not show a synergistic effect.
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