Biological control of Lobesia botrana (Lepidoptera: Tortricidae) larvae by using different formulations of Bacillus thuringiensis in 11 vine cultivars under field conditions.

This work describes the results of an experiment that was conducted in the vineyard of the American Farm School, Thermi, Thessaloniki Greece, during 2001. Its aim was to study the efficacy of two formulations of Bacillus thuringiensis Berliner (wettable powder and dust) to control the larvae of Lobesia botrana Denis & Schiffermueler (Lepidoptera: Tortricidae). The experimental results showed that the two formulations of B. thuringiensis are significantly more effective than the control, the dusting being more effective in most cultivars (Asyrtico, Sauvignon blanc, Debina, Athiri, Agiorgitico, Limnio, Syrah, and Cabernet sauvignon), and the spraying in a few cultivars (Xinomavro, Roditis, and Chardonnay). Dusting in the blue-black cultivars was found to be more effective than spraying, this not being the case in the yellow-green cultivars. This fact should be taken into consideration when cultivars of different color were planted in the same field. Single dusting proved to be better in cultivars with loose, average and dense berry cluster compactness, whereas double spraying gave better results in compact cultivars.