The present invention relates to pesticidal mixtures comprising as active compounds1) at least one pesticidal active 3-arylquinazolin-4-one compound I of formula (I):wherein R1, R2, R3, R4, k and n are defined in the description;and2) at least one active compound II selected from a group M comprising acteylcholine esterase inhibitors, GABA-gated chloride channel antagonists, sodium channel modulators, nicotinic acteylcholine receptor agonists/antagonists, allosteric nicotinic acetylcholine receptor activators, chloride channel activators, juvenile hormone mimics, homopteran feeding blockers, mit grow inhibitors, inhibitors of mitochondrial bATP synthase, uncouplers of the oxidative phosphorylation, inhibitors of the chitin biosynthesis, moulting disruptors, ecdyson receptor agonists, octamin receptor agonists, inhibitors of the MET, voltage-dependent sodium channel blockers, inhibitors of the lipid synthesis, ryanodine receptor modulators and other compounds as defined in the description, in synergistically effective amounts.The invention relates further to methods and use of these mixtures for combating and controlling insects, arachnids or nematodes in and on plants, and for protecting such plants being infested with pests, especially also for protecting plant proparagation material, such as seeds.