This invention provides a harmful organism control composition having an excellent harmful organism control effect and comprising as an effective ingredient the following 4-(2-butynyloxy)-5-fluoro-6-(3,5-dimethylpiperidino)-pyrimidine (X):
and a hydrazide compound represented by formula (I):
wherein A
1
and A
2
represent, for example, an oxygen atom; R
1
, R
2
, and R
3
represent, for example, a hydrogen atom, a C
1-6
alkyl group optionally substituted by a halogen atom; and Q represents, for example, a methoxycarbonyl group.
A hydrazide compound represented by the formula (1):
(wherein R
1
, R
2
, R
3
, R
4
, A
1
, A
2
, J, Q and n are defined in the specification) has excellent pesticidal activity.