Biology, Ecology and Behaviour of Aphidophagous Insects THE BIOLOGICAL CONTROL OF Aulacorthum solani (KALTENBACH)

To improve the control of the foxglove aphid (Aulacorthum solani) in greenhouse sweet pepper, several trials on three trophic levels have been conducted. Two different lines of Aphelinus abdominalis were compared on flight capacity, parasitation and predation. One line was significantly better in parasitation of A. solani (6.3 vs 0.2 mummies/female/day). This line performed also better at lower temperatures (15-18º C.) in flight capacity. Predation was the same for both lines (2 aphids/female/day). The honeydew of A. solani was tested as a food source on Aphidius spp. The life span of Aphidius on this honeydew was 4 days which was equal to water and half of sucrose. On 100 ha. of commercially grown sweet pepper a banker plant system (wheat, Sitobion avena, A. abdominalis) was used. In general growers were able to reduce the number of chemical corrections from 7 to around 3. In sweet peppers grown under glass there is a natural oscillation of 4-5 weeks in flowering and fruit set. We observed large differences in aphid growth depending on this vegetative or fruiting phase. The practical considerations how to adjust the biological control still has to be investigated