In crop production in the fields of agriculture, horticulture and the like, the damage caused by insect pests etc. is still immense, and insect pests resistant to existing insecticides have emerged. Under such circumstances, the development of novel agricultural and horticultural insecticides is desired. The present invention provides an agricultural and horticultural insecticide comprising, as an active ingredient, a 3H-pyrrolopyridine compound represented by the general formula (1): (wherein A 1 , A 2 , and A 3 each represent a nitrogen atom or a CH group, R 1 represents an ethyl group, R 2 and R 4 each represent a hydrogen atom, R 3 and R 7 each represent a haloalkyl group, R 5 and R 6 each represent a fluorine atom, and m represents 0 or 2), an N-oxide thereof or a salt thereof； and a method for using the agricultural and horticultural insecticide.
