Quinoline compound, and bactericidal agent for agricultural and horticultural use

A compound represented by the formula (II), an N-oxide compound, or a salt thereof. In the formula (II), R 1 is a hydrogen atom, a substituted or unsubstituted C1-6 alkyl group, or a halogeno group. R2 is a substituted or unsubstituted 5- to 6-membered heteroaryl group. R3 is a substituted or unsubstituted C6-10 aryl group or a substituted or unsubstituted 5- to 10-membered heteroaryl group. Y is an oxygen atom, a nitrogen atom or a sulfur atom. A1, A2, A3 and A4 are each independently a carbon atom or a nitrogen atom. However, two or more of A1 to A4 can not be nitrogen atoms. X is a substituent. n represents the number of chemically acceptable Xs, and is an integer of 0 to 5. When n is 2 or more, X may be the same or different.