TESTING OF THE NEW INSECTICIDES FORMULATION FOR MAIZE SEEDS TREATMENT AGAINST Tanymecus dilaticollis Gyll IN LABORATORY CONDITIONS

Maize leaf weevil (Tanymecus dilaticollis Gyll) produce high damages at maize crops, in south and south-east of the Romania. Until end of the year 2013, seed treatments were generalized. After neonicotinoid treatment restrictions, as result of EU directive 485/2013, no insecticides remain available, for maize seeds treatment, against T. dilaticollis, in Romania. As result, researches from last years were focused for finding possible alternatives to replace neonicotinoid insecticides, used for maize seed treatments, in eventuality of permanent ban of these, in 2016. In this paper, authors collective present results concerning testing of two active ingredients (cyantraniliprole and thiacloprid), for controlling of the maize leaf weevil, used high pest pressure, in laboratory conditions. The results obtained at variants treated with cyantraniliprole, thiacloprid or different combinations of these two active ingredients were compared with one standard active ingredient, clothianidin and control (untreated) variant. In this laboratory assessment, in conditions oh high pest pressure, after 8 days from pots infestation with T. dilaticollis adults, higher insect mortality was registered in case of variant treated with clothianidin active ingredients (67.50%). At the rest of the treated variants, insects mortality, after 8 days of observations, presented low values, ranged between 6.25 and 12.50%. On a scale from 1 (not attacked) to 9 (total damage), attack intensity of the T. dilaticollis at the maize untreated plants, was of 8.67. In conditions of high pest pressure, untreated plants were destroyed. The lowest attack intensity values was registered in case of variant treated with clothianidin active ingredient (I=3.92). Cyantraniliprole and thiacloprid active ingredients didn’t provide effective protections of the maize plants, in first vegetation stages (BBCH 10-14), against T. dilaticollis attack, in conditions of high pest pressure.