Insecticidal and acaricidal agent

A pyrazolylacrylic acid compound of the formula (II):

• 16
• wherein A1 represents a phenyl group substituted at, at least, the 4-position or a phenyl group substituted at 3- and 5-positions independently from each other, the substituents being selected from the group consisting of halogen, alkyl, haloalkyl, alkoxyl, haloalkoxyl, alkylthio, aryl which are optionally substituted, aryloxy which are optionally substituted and heteroaryloxy which are optionally substituted, the substituents of the aryl, aryloxy and heteroaryloxy are selected from the group consisting of halogen, alkyl, haloalkyl, alkoxyl, haloalkoxyl and alkylthio;
• R1 represents hydrogen;
• halogen;
• alkyl which is optionally substituted;
• an alkenyl which is optionally substituted;
• alkynyl which is optionally substituted;
• alkoxyl which is optionally substituted;
• or aryl which is optionally substituted;
• and
• R2 represents hydrogen, alkyl;
• haloalkyl;
• or aryl which is optionally substituted;
• with the proviso that the following compounds are excluded:
• methyl α-{1,3-dimethyl-4-(4-chlorophenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1,3-dimethyl-4-(4-fluorophenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1,3-dimethyl-4-(4-methoxyphenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1,3-dimethyl-4-(4-methylphenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1,3-dimethyl-4-(3,4-dichlorophenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1,3-dimethyl-4-(3-chloro-4-methoxyphenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1,3-dimethyl-4-(2,4-dichlorophenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1-methyl-3-trifluoromethyl-4-(4-chlorophenylethynyl)-5-pyrazole}-,-methoxyacrylate;
• methyl α-{1-methyl-3-trifluoromethyl-4-(4-fluorophenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• methyl α-{1-methyl-3-trifluoromethyl-4-(3-chloro-4-methoxyphenylethynyl)-5-pyrazole}-β-methoxyacrylate;
• and methyl α-{1-methyl-3-trifluoromethyl-4-(2,4-dichlorophenylethynyl)-5-pyrazole}-β-methoxyacrylate.

A pyrazolylacetic acid compound of the formula (IV):

• 17
• wherein R1 represents hydrogen;
• halogen, alkyl which is optionally substituted;
• alkenyl which is optionally substituted;
• alkynyl which is optionally substituted;
• alkoxyl which is optionally substituted;
• or aryl which is optionally substituted,
• R2 represents hydrogen;
• alkyl;
• haloalkyl;
• or aryl which is optionally substituted;
• R′ represents alkyl;
• and
• Z represents hydrogen or halogen.