Synergistic Insecticidal Activity of Cynanchum acutum and Sonchus maritimus Extracts against Aphids

This study evaluated the insecticidal effectiveness of aqueous extracts from Cynanchum acutum L. (climbing vine swallowworts), Sonchus maritimus L. (Sow Thistle) and their 1:1 mixture against aphids collected in El Oued Province.

Plant materials were prepared using standard extraction techniques and bioassays were conducted on adult and larval aphids at five different concentrations, with mortality noted after 24 and 48 hours.

Probit analysis showed significant, dose- and time-dependent mortality for all extracts, with larvae generally more vulnerable than adults. The mixture was the most effective, showing the lowest LC₅₀ values: from 0.73 mg/mL (adults, 24 h) to 0.56 mg/mL (adults, 48 h) and from 0.49 mg/mL to 0.12 mg/mL for larvae. Sonchus maritimus L. alone exhibited potent activity against larvae (LC₅₀ = 0.025 mg/ml at 48 h), while Cynanchum acutum L. was less powerful. Nearly complete larval mortality was observed at concentrations above 0.666 mg/ml for all extracts. These findings suggest that mixed botanical extracts have great potential as sustainable, potent agents for aphid control, justifying further field testing and safety evaluations.