1,4 diaryl-2,3-difluoro-2-butene insecticidal and acaricidal agents

Compounds of formula I

• 26
• wherein
• Ar is phenyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy, C1-C4-haloalkoxy or hydroxy groups,
• 1- or 2-naphthyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, or
• a 5- or 6-membered heteroaromatic ring containing one to four nitrogen atoms or one to three nitrogen atoms and one sulfur atom or oxygen atom or one or two sulfur and/or oxygen atoms which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups;
• R is C2-C6-alkenyl, C4-C6-cycloalkenyl or C1-C2-alkoxy-C2-C6alkyl;
• Ar1 is phenoxyphenyl which is unsubstituted or substituted with any combination of from one to six halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
• phenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
• biphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, phenoxypyridyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
• benzylpyridyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
• benzylphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
• benzoylphenyl which is unsubstituted or substituted with any combination of from one to five halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups,
• 1- or 2-naphthyl which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, or
• a 5- or 6-membered heteroaromatic ring containing one to four nitrogen atoms or one to three nitrogen atoms and one sulfur atom or oxygen atom or one or two sulfur and/or oxygen atoms which is unsubstituted or substituted with any combination of from one to three halogen, C1-C4-alkyl, C1-C4-haloalkyl, C1-C4-alkoxy or C1-C4-haloalkoxy groups, and
• the optical isomers thereof, and
• the (E)- and (Z)- isomers thereof.