Guanicide compound and fungicide

A compound of a formula [I] or a salt thereof:

• in the formula [I], Y represents a divalent group of a formula [II], [IIa], or [IIb]:
• in the formula [II], R7 to R9 each independently represents a hydrogen atom, a nitro group, a cyano group, an unsubstituted or substituted hydrocarbon group, an unsubstituted or substituted heterocyclyl group, a hydroxyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkoxycarbonyl group, an unsubstituted or substituted aryloxy group, an unsubstituted or substituted amino group, an unsubstituted or substituted alkylsulfonyl group, an unsubstituted or substituted arylsulfonyl group, an unsubstituted or substituted heterocyclylsulfonyl group, an unsubstituted or substituted alkylcarbonyl group, an unsubstituted or substituted arylcarbonyl group, or an unsubstituted or substituted heterocyclylcarbonyl group, both R8 and R9, both R7 and R8, or both R7 and R9 may form a divalent organic group by being bonded together, both R8 and a substituent on X may form a divalent organic group by being bonded together, and * represents a binding site;
• in the formula [IIa] and the formula [IIb], R10 to R15 each independently represents a hydrogen atom, a nitro group, a cyano group, an unsubstituted or substituted hydrocarbon group, an unsubstituted or substituted heterocyclyl group, a hydroxyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkoxycarbonyl group, an unsubstituted or substituted aryloxy group, an unsubstituted or substituted amino group, an unsubstituted or substituted alkylsulfonyl group, an unsubstituted or substituted arylsulfonyl group, an unsubstituted or substituted heterocyclylsulfonyl group, an unsubstituted or substituted alkylcarbonyl group, an unsubstituted or substituted arylcarbonyl group, or an unsubstituted or substituted heterocyclylcarbonyl group, both R10 and R11, both R10 and R12, both R13 and R14, or both R14 and R15 may form a divalent organic group by being bonded together, and * represents a binding site,
• X and Z each independently represents an unsubstituted or substituted alkylene group, an unsubstituted or substituted alkenylene group, an unsubstituted or substituted alkynylene group, -Ta-O-Tb-, -Ta-S-Tb-, or -Ta-N(R21)-Tb-, wherein Ta and Tb each independently represents a single bond or an unsubstituted or substituted alkylene group, and R21 represents a hydrogen atom, an unsubstituted or substituted hydrocarbon group, an unsubstituted or substituted heterocyclyl group, a hydroxyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkoxycarbonyl group, an unsubstituted or substituted aryloxy group, an unsubstituted or substituted amino group, an unsubstituted or substituted alkylsulfonyl group, an unsubstituted or substituted arylsulfonyl group, an unsubstituted or substituted heterocyclylsulfonyl group, an unsubstituted or substituted alkylcarbonyl group, an unsubstituted or substituted arylcarbonyl group, or an unsubstituted or substituted heterocyclylcarbonyl group,
• Q1 and Q2 each independently represents a single bond, an unsubstituted or substituted phenylene group, —CH═CH—, —C≡C—, —O—, —S—, —SO—, —SO2—, or —N(R22)—, wherein R22 represents a hydrogen atom, an unsubstituted or substituted hydrocarbon group, an unsubstituted or substituted heterocyclyl group, a hydroxyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkoxycarbonyl group, an unsubstituted or substituted aryloxy group, an unsubstituted or substituted amino group, an unsubstituted or substituted alkylsulfonyl group, an unsubstituted or substituted arylsulfonyl group, an unsubstituted or substituted heterocyclylsulfonyl group, an unsubstituted or substituted alkylcarbonyl group, an unsubstituted or substituted arylcarbonyl group, or an unsubstituted or substituted heterocyclylcarbonyl group,
• A1 and A2 each independently represents an unsubstituted or substituted divalent heterocyclic compound residue, an unsubstituted or substituted divalent aromatic hydrocarbon residue, or —N(R23)—, wherein R23 represents a hydrogen atom, an unsubstituted or substituted hydrocarbon group, an unsubstituted or substituted heterocyclyl group, a hydroxyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkoxycarbonyl group, an unsubstituted or substituted aryloxy group, an unsubstituted or substituted amino group, an unsubstituted or substituted alkylsulfonyl group, an unsubstituted or substituted arylsulfonyl group, an unsubstituted or substituted heterocyclylsulfonyl group, an unsubstituted or substituted alkylcarbonyl group, an unsubstituted or substituted arylcarbonyl group, or an unsubstituted or substituted heterocyclylcarbonyl group,
• R1 to R6 each independently represents a hydrogen atom, an unsubstituted or substituted hydrocarbon group, an unsubstituted or substituted heterocyclyl group, a hydroxyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkoxycarbonyl group, an unsubstituted or substituted aryloxy group, an unsubstituted or substituted amino group, an unsubstituted or substituted alkylsulfonyl group, an unsubstituted or substituted arylsulfonyl group, an unsubstituted or substituted heterocyclylsulfonyl group, an unsubstituted or substituted alkylcarbonyl group, an unsubstituted or substituted arylcarbonyl group, or an unsubstituted or substituted heterocyclylcarbonyl group, R1 and R2 may form a 4- to 8-membered ring by being bonded together with two nitrogen atoms binding therewith and a carbon atom binding with the two nitrogen atoms, R2 and R3 may form a 4- to 8-membered ring by being bonded together with a nitrogen atom binding therewith, R4 and R5 may form a 4- to 8-membered ring by being bonded together with two nitrogen atoms binding therewith and a carbon atom binding with the two nitrogen atoms, or R5 and R6 may form a 4- to 8-membered ring by being bonded together with a nitrogen atom binding therewith.