FIELD TRIALS ON MATING DISRUPTION TO CONT ROL THE EUROPEAN GRAPE MOTHEUPOECILIA-AMBIGUELLA HBN

In 1984 and 1985 field trials on mating disruption of the European gra pe moth Eupoecilia ambiguella Hbn. were carried out on a large scale ( 117 ha) in the vine growing region of Rhine-Palatinate. The pheromone quantities used varied between 25 and 150 g Z-9-DDA (2.6 % E) per hect are, the number of pheromone sources (HERCON Dispensers) from 50 to 10 00/ha (handapplication) and 10 000/ha (application by helicopter). Eff iciency was checked with different methods: disorientation of male mot hs using pheromone traps, mating reduction by dissection of female mot hs caught in bait traps, damage assessment. Disorientation always amou nted to more than 99 %. Damage assessment revealed different levels of efficiency depending on the site of the treated plots: whereas in are as with low or moderate insect population good results were obtained w ith 25 g pheromone and 180 sources/ha, this treatment, however, failed in plots with high population pressure. By increasing the pheromone q uantity and/or the number of sources per hectare, larval attack was re duced below the damage threshold in these areas with only few exceptio ns. The percentage of unmated females amounted to 83 % in the pheromon e treated area versus 13 % in untreated. These results were obtained b y applying the pheromone dispensers by hand. The application of minifl akes by helicopter was not successful. Since 1986 the mating disruptio n technique for control of E. ambiguella has been registered in German y: at first against the 2nd generation with a recommended dosage of 50 g Z-9-DDA and 500 sources/ha, since 1991 against both generations, re commending one application of 170 g Z-9-DDA/ha and 500 sources. In are as with high population densities, these have to be reduced by specifi c control measures prior to the use of the mating disruption technique .