2017 | 70/1 | 27–39 | 4 Figs. | 6 Tabs. | www.geologia-croatica.hr Journal of the Croatian Geological Survey and the Croatian Geological Society Croatian diatomites and their possible application as a natural insecticide Ines Galović1, Josip Halamić1, Anita Grizelj1, Vlatka Rozman2, Anita Liška2, Zlatko Korunić3, Pavo Lucić2 and Renata Baličević2 1 Croatian Geological Survey, Department of Geology, Sachsova 2, 10000 Zagreb, Croatia; (
[email protected]) 2 University of Josip Juraj Strossmayer in Osijek, Faculty of Agriculture in Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia 3 Diatom Research and Consulting Inc., 14 Tidefal Dr. Toronto, ON, MW 1J2, Canada doi:10.4154/gc.2017.04 Abstract Article history: In recent decades, there has been an increase in the use of diatomaceous earth (DE) as a natu- Manuscript received November 17, 2016 ral insecticide because of its low mammalian toxicity, worker safety, low risk of food residues and Revised manuscript accepted February 24, 2017 the occurrence of resistant insect populations associated with the use of chemical insecticides. Available online February 28, 2017 Therefore there is potential for research into known but previously undescribed Croatian mid- Miocene marine diatomites from the perspective of their potential as proper DE that could be mixed with plant extracts as a new formulation for grain storage protection. The marine diato- mites belong to the Paratethyan near shore environment, deposited in the upwelling zone during a mid-Miocene temperate climate. Palaeontological, mineral and geochemical analyses were done on ten promising marly sediments from 26 outcrops and one borehole from the North Cro- atian Basin. The most important ingredient of diatomaceous sediments is silica (biogenic opal-A and SiO2 bound in other silicate minerals including quartz, clay minerals, micas, etc.).