Sublethal Effects of Solanum tuberosum and Lycopersicon esculentum Leaf Extracts on Tenebrio molitor and Harmonia axyridis

Repellent or attractant activity of extracts obtained from Solanum tuberosum and Lycopersicon esculentum leaves were tested against Tenebrio molitor (Coleoptera: Tenebrionidae) and Harmonia axyridis (Coleoptera: Coccinellidae). Different developmental stages of the insects (larvae of different age and imagoes) were exposed to the extracts which is present in the substratum. Extracts were used in different concentrations of 1, 10, 100 or 1000 ppm. Distilled water was used as control. In this study, we observed migration of the insects towards the exposed area especially with lower concentrations of extracts which is taken as attractant activity. In other cases, insects showed migration towards control areas which is taken repellent activity. The reaction differed between both insect species, as well as between younger, older larvae and adults of T. molitor. Therefore we infer from this study that both plants may be a source of substances which will be used in insect pest management for plant protection.