Larvicidal effect of Achillea biebersteinii Afan. (Asteraceae) essential oil against larvae of pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermuller, 1775) (Lepidoptera: Notodontidae)

The pine processionary moth, Taumetopoea pityocampa (Denis & Schiffermuller, 1775) (Lepidoptera: Notodontidae), is an important pest of coniferous trees in the forests of Turkey and throughout the world. In order to control this pest, different methods such as mechanical, biological, and chemical control have been used. However, this pest is still a major problem in Turkey, as well as globally. The study aimed to investigate the larvicidal effect of essential oil obtained from Achillea biebersteinii Afan. (Asteraceae) in different doses (10, 15, and 20 mu L. Petri(-1)) over time (12, 24, 36, and 48 h) against T. pityocampa larvae in laboratory conditions (25 degrees C (+/- 2), 65% (+/- 5) RH, and 14/10 L/D). At the end of the study, the larvae mortalities were observed to range from 3.33% to 100%. While the highest mortality rates (between 40% and 100%) were recorded on first and second instar larvae, the lowest mortality rates (between 3.3% and 73.3%) were determined for third, fourth, and fifth instar larvae. The results showed that A. biebersteinii essential oil has a critical larvicidal effect on the first, second, third, fourth, and fifth instar larvae of T. pityocampa in comparison with the controls and can be used in controlling the larvae of this pest.