3,6 -disubstituted- 1,2,4,5 -tetrazines; 3 - (2-bromophenyl) - 6 - (2,6 - difluorophenyl) - 1,2,4,5 -tetrazine; 3,6-bis (2,6-difluorophenyl) - 1,2,4,5 -tetrazine; 3 - (2-chlorophenyl) - 6 - (2,6-difluorophenyl) - 1,2,4,5 -tetrazine; process for the production of compounds; preparation of acaricidal, larvicidal and ovicidal action; translaminar ovicidal preparation; ovicidal preparation with transovarian action; process to reduce the number of mites, their larvae and eggs; and process for the production of a preparation with acaricide, larvicide and ovicide action.