Larvicidal Effect of Some Essential Oils Against Larvae of the European Pine Sawfly [Neodiprion Sertifer (Geoff.)]

Abstract

Many of the species that cause damage to pine trees by feeding on needle leaves, and trees without leaves may be vulnerable to secondary pests as well as increment loss. One of the important leaf pests that damage Turkish red pine (Pinus brutia) and the Anatolian Black pine (Pinus nigra A.Rich) in Turkey is the pine sawfly Neodiprion sertifer (Geoff.). Only mechanical and chemical control methods are carried out with this pest. Due to the negative effects of chemical control methods on the ecosystem and nature, alternative methods have come to the fore front in recent years. One of them is the use of essential oils against harmful insects. The aim of the study is determine to larvicidal effects of some essential oils against larvae of N. sertifer. To achieve of this aim our objective is applied three different dosages (0.1%, 0.5% and 1.0%) of essential oils obtained from Eucalyptus camaldulensis, Melissa officinalis and Origanum onites plants to the 4th and 5th instar larvae of pine sawfly. Trials were carried out in the laboratory under controlled conditions ( 25 +/- 5 degrees C temperature and 65 +/- 5% proportional humidity). Dead larvae in each box were counted 12, 24, 36 and 48 hours after application. According to the application dosages, the highest deaths of N. sertifer larvae occurred at 1% doses of all three essential oils. It was observed that the larval mortality rates increased as the dosages increased. As a result, essential oils of all three plant species were found to be hopeful in the controlling of N. sertifer, of which essential oil of O.onites was found more effective on the 4th and 5th instar larvae than the essential oils of the other two plant species. They have shown that essential oils can be a potential alternative to synthetic insecticides in the control of pine sawfly.