Natural insecticides based on extracts from seed kernels of the neem tree, Azadirachta indica A. Juss (Meliaceae), have gained importance for pest management in the last decades. Due to the public pressure to eliminate synthetic chemical pesticides, biological products for pest management are considered as a promising alternative. Neem products are especially convenient for home and garden use and for high-value crops such as ornamentals. Their low persistence in the environment and low mammalian toxicity (Sundaram, 1996; Raizada et al., 2001;Boeke et al., 2004;Kleeberg, 2004) are advantageous for use in public areas. One common pest of roses is the rose aphid, Macrosiphum rosae L. (Hemiptera: Aphididae). It has an almost global distribution and infests all sorts of Rosa species as its primary host plant. In Europe, M. rosae can be found on roses from spring to autumn. Preferred feeding sites are young leaves and developing buds. Severe

Many studies in the last decades addressed the antifeedant and repellent effects of neem (Azadirachta indica)-based pesticides on arthropod herbivores with azadirachtin as the leading active ingredient. However, results for aphids regarding repellence and feeding were often contradictory and mainly based on laboratory studies with self-made neem extracts in high concentrations. Moreover, no data are available on the presence of azadirachtin in the phloem of treated plants—the tissue that most aphids feed on. We investigated how the application of the commercial neem product NeemAzal-T/S onto only one plant half (upper or lower) affects nymphs of the aphid Macrosiphum rosae in clip cages on the untreated plant half. Results for aphid mortality indicate that active ingredients of NeemAzal-T/S are translocated both upwards and downwards in rose plants and that active ingredients are transported in the phloem. Furthermore, we investigated whether NeemAzal-T/S has a repellent or antifeedant effect on M. rosae. A choice test in the greenhouse as well as the quantification of honeydew excretion and electrical penetration graph analysis do not show differences in settling or feeding on untreated and NeemAzal-T/S-treated rose plants. Collectively, our data show that the effect of approved concentrations of NeemAzal-T/S on M. rosae is based on the toxicity after feeding on treated plants, not on starvation.