Biological efficacy evaluation of mating disruption against the grape berry moth, Lobesia botrana, in grape in glasshouses.

The grape berry moth, Lobesia botrana, is an important pest of grapes. In Belgium, severe losses of production appeared due to the presence of L. botrona in grapes commercially grown in glasshouses. In 2010 mating disruption became a key pest management tactic in Flemish pip fruit orchards after being tested for several years. In other (European) countries, mating disruption is already applied in grapes but there is no registration in Belgium for use in grapes. Searching for an interesting residue free technique for application in small glasshouses, we evaluated the effect of mating disruption for control of L. botrana under protected conditions (glasshouse trials) during three consecutive years (2010-2012). A prerequisite for successful mating disruption is the treatment of large contiguous areas, as the pheromone product will not remain in sufficient quantities on narrow sites and, moreover, a larger portion of the crop remains at risk from migrating mated females. The glasshouses are rather small, however, we hypothesized that these so called border effects are not present due to the secluded spaces of the glasshouses. Pheromone dispensers were deployed and flights of L botrano moths were monitored (pheromone traps/UV-traps) during the whole time period of the trials. In the mating disrupted glasshouses hardly any moth was caught anymore in pheromone traps, in contrast to UV-traps or catches by pheromone traps in comparable non-mating disrupted glasshouse compartments. This indicates the incapability of the males to localize sex pheromone sources, and hence, the inability of finding females for mating. In line with these flight monitoring data, the nearly absence or strongly decreased L. botrana caused damage symptoms in the mating disrupted glasshouses demonstrates the benefits of the mating disruption technique under protected conditions of grape growing in glasshouses.