The infestation of Vicia faba L. (Fabaceae) by Aphis fabae (Scop.) (Homoptera: Aphididae) under the influence of Lamiaceae (Ocimum basilicum L. and Satureja hortensis L.)

The system Vicia faba-Aphis fabae fabae was studied under the influence of Ocimum basilicum (basil) and Satureja hortensis, in a wind tunnel, in the greenhouse and in field experiments. In the wind tunnel at 20 degrees C both Lamiaceae were deterrent for A. fabae, and S. hortensis proved to be more deterrent than O. basilicum. In experiments in the greenhouse at low temperatures (average minimum 14.6 degrees C, average maximum 24.1 degrees C), A. fabae colonised first and significantly more intense Vicia fabae (field beans) not surrounded by O. basilicum or S. hortensis. At high temperatures (average minimum 18.0 degrees C, average maximum 38.5 degrees C) this relation was inverted: Vicia faba surrounded by the two Lamiaceae were preferred for colonisation (Ocimum basilicum significantly). It showed that pots with Lamiaceae were no obstacle for the aphids to reach Vicia faba. In strip cropping in the field, the repellent effect of Ocimum basilicum proved to be stronger than of Satureja hortensis. In 2002 there was observed only a tendency of lower aphid attack of field beans intercropped with Lamiaceae, while in 2004 and 2005 the infestation of Vicia faba by Aphis fabae was significantly lower in plots intercropped with basil. In plots with Satureja hortensis as intercrop, Vicia faba were significantly lower infested, after 3 weeks. The differences between the results of the wind tunnel/greenhouse at low temperatures, and the field experiments concerning the deterrence by Satureja hortensis cannot be explained. But basing on our results with Ocimum basilicum and those published by other authors, it is recommended to follow up intercropping, after a sincere analysis in every case, in favour of agronomists.