There has been a demand for the development of novel agricultural and horticultural insecticides because pests and the like still cause heavy damage to crops produced in agriculture horticulture and the like and pests resistant to existing chemical agents have emerged etc. Under these circumstances the present invention provides: an agricultural and horticultural insecticide containing as an active ingredient a 3H-pyrrolopyridine compound represented by general formula (1) (in the formula A1 A2 and A3 each represent a nitrogen atom or a CH group R1 represents an ethyl group R2 and R4 each represent a hydrogen atom R3 and R7 each represent a haloalkyl group R5 and R6 each represent a fluorine atom and m represents 0 or 2.) and an N-oxide thereof or salts thereof； and a method for using the agricultural and horticultural insecticide.
