Abstract: An item (including a sheet or lamina) is treated to proof the item, or a surface or area in which the item is placed, against crawling insects, by printing or spraying the item, or immersing the item in, a pesticide/liquid carrier solution and then drying the solution to remove the liquid carrier, to leave a residue pesticide in or on the material of the item to be contacted by the crawling insects. The pesticide/carrier solution may be applied to the item by mixing the pesticide in a suitable ink and printing the solution onto the item by flexopress, offset or letterpress printing methods or by silk-screening methods.