LARVICIDAL EFFECT OF SOME PLANT EXTRACTS ON THE PINE PROCESSIONARY MOTH, Thaumetopoea pityocampa (Denis & Schiffermuller) IN LABORATORY CONDITIONS

Abstract

The pine processionary moth, Taumetopoea pityocampa (Denis and Schiffer-muller) is one of the most widespread defoliator insects found in the forest areas of Turkey. Although different methods have been used to control this major forest pest up to now, the problem is still going on largely unsolved in the forest areas of Turkey. The objective of this study was to determine larvicidal effects of extracts obtained from six different plant species, Achillea wilhelmsii C. Koch, Nepeta meyeri Benth., Satureja hortensis L., Origanum onites L., O. rotundifolium Boiss., Tanacetum argyrophyllum (C. Koch) and on the 2nd, 3rd, and 4th instar larvae of T. pityocampa in laboratory conditions. Test the toxicity of six plant extracts against to the 2nd, 3rd, and 4th instar larvae of T. pityocampa, 10 larvae of this insect with 15 gr amounts fresh needles (1 year old) of Pinus brutia were placed to Petri dishes (9 x 1.5 cm deep). Each dose was dissolved in acetone and 0.25, 0.5 and 1 mg of the plant extracts found in 1 ml solution were sprayed on the 2nd, 3rd, and 4th instar larvae of T. pityocampa in the Petri dishes, corresponding to 2.08, 4.16 and 8.33 mg.l(-1) air concentrations. Petri dishes were covered with a lid. All tests carried out at 26 degrees C (+/- 2), 60% (+/- 5) relative humidity and 14/10 h light/dark photoperiod in laboratory conditions. When exposure, mortality of the larvae was after the determined at 24, 48 and 96 h. Petri dish applied with sterile water and acetone were used as control group. All the tests were made in triplicate. The results showed that six plant exracts have a larvicidal effect on the 2nd, 3rd and 4th instar larvae of T. pityocampa in comparison with controls. Therefore, these naturally occurring plant extracts could be useful for managing the larvae populations of T. pityocampa.