Enhancing the potential of the egg parasitoid of the grape berry moth, trichogramma semblidis(Auriv.)(Hym., Trichogrammatidae)by means of alternative hosts on stinging mettles in the wine-growing area of the Ahr Valley, Germany

摘要

In the present study a method has been tested to enhanced the potential of Trichogramma semblidis(Auriv.)(Hym., Trichogrammatidae), which is an egg parasitoid of the grape berry moth, by offering alternative hosts on stinging nettles in the wine-growing area of the Ahr Valley, Germany. The nettles were planted into the plots in three different lay-outs. With this method the parasitization of T.semblidis could be increased up to 90/100 at the first pest generation in May. The resulting number of larvae per inflorescence was Only 0,05 to 0,1, but 0,5 in the control plots. This effect was slightly lower during the second pet generation in July, when 0,13 to 0,28 larvae per grape could be found, while there were up to 0,65 larvae in the control.