Insecticide potential of diatomaceous earth from Croatia
Abstract: Diatomaceous earth (DE) is a geological deposit consisting of the fossilized skeletonsof numerous species of siliceous marine and fresh water one-cellular organisms, particularlydiatoms and other algae. The skeletons are made of amorphous silicon dioxide. DE is probablythe most effective natural inert dust used as an insecticide. DE is a low toxicity, naturalinsecticide. Several formulations of DE are registered and used as stored product protectioninsecticides around the world. The objective of the research was determination of the potentialinsecticide effectiveness of Croatian DE against stored products pests and the comparison of theireffectiveness with the effectiveness of standard DE sample. One sample of the Croatian DE wasselected and investigated. As a standard DE sample, the German fresh water DE SilicoSec wasincluded into the experiment. SilicoSec formulation is registered as a grain protectant andbelongs into a group of the most effective DEs in the world. The effectiveness of particle sizefractions of the Croatian DE from most to least effective is: 0-20 microns (μm), 0-45μm 0-150μm, 20-45μm and 45-150μm. The Croatian DE sample applied at 600mg/kg containingparticle size 0-45μm showed with over 90% mortality after 1 day for Cryptolestes ferrugineus,after 3 days for Sitophilus oryzae, after 7 days for Rhyzopertha dominica and after 25 days forTribolium castaneum. SilicoSec caused 100% mortality these insects at the same or shorter timeperiods The effectiveness of the Croatian DE containing particles smaller than 45μm was equallyeffective against the progeny if compared with the effectiveness of the standard DE.The authors conclude that Croatia has potential sources of DEs for ecological acceptableinsecticide production and it is important to find new localities with even better sources of DEs.It can be a new safe and natural insecticide product from Croatia.