Repellency and toxicity of three Impatiens species (Balsaminaceae) extracts on Myzus persicae Sulzer (Homoptera: Aphididae)

The extracts of Impatiens noli-tangere, I. parviflora and I. glandulifera (Balsaminaceae) were evaluated for their effect on green peach aphid (Myzus perssicae), an important insect pest of many plants. All the extracts showed insecticidal and repellent activity. After 54 h of exposure, the most active extract was Impatiens parviflora with 99.7 and 90.0 % mortality at 0.5 and 0.1 % concentrations, respectively, and with highly percent repellency (90-100%) at different times. The extract of I. parviflora contained tryptophan (2.13 mg/g); 2methoxy-1,4-naphthoquinone (0.02 mg/g), total flavone (7.64 mg/g) and total derivatives of caffeic acid (15.60 mg/g).