The present invention relates to 1-(imidazolin-2-yl)amino-1,2-diphenylethane compounds of the formula I and their agriculturally acceptable salts, wherein A is a radical of the formula A1 or A2. The invention relates also to agricultural compositions and to seed comprising at least one compound I and/or a salt thereof, as well as a method of combating animal pests, a method for protecting crops from attack or infestation by animal pests and a method for protecting non-living materials from attack or infestation by animal pests, a method for the protection of seeds from animal pests and of the seedlings' roots and shoots from animal pests by applying a pesticidally effective amount of at least one 1-(imidazolin-2-yl)amino-1,2-diphenylethane compound I and/or a salt thereof.