Toxic effects of Bacillus thuringiensis kurstaki (var. serotype: H-7) on different life stages of Archips rosana (Linnaeus, 1758) (Lepidoptera: Tortricidae)

Archips rosana is a species of nocturnal butterfly (moth) known as leafroller belonging to the family Tortricidae of the order Lepidoptera. A. rosana larvae of the Tortricidae family cause damage to flowers, buds, leaves and fruits of plants according to the time they are found. It causes economic losses in plants used in various ornamental plants, horticulture and fruit production. For this reason, various pesticides are used in the fight against pests. Due to the intensive and unconscious use of these pesticides, the natural balance is disrupted and biodiversity is damaged. The use of bioinsecticides instead of chemical insecticides, which are currently used uncontrollably in agricultural lands is important for the environment and human health. In this study, we aimed to examine the effects of the bioinsecticide, whose active ingredient is Bacillus thuringiensis kurstaki (var. serotype: H-7) (BIOBIT WP 16000 IU/mg), on different life stages (4th and 5th larvae, prepupae, pupae and adults) of Archips rosana (Linnaeus, 1758) (Lepidoptera: Tortricidae). In this thesis, larvae of A. rosana were collected from in Trakya University Balkan Arboreatum (Edirne province) between April and June, especially from Ulmus minor Miller (Ulmaceae) species not exposed to pesticides, with minimal direct hand contact and transported to the laboratory. The last 4th and 5th larvae, prepupae, pupae and adults stage of A. rosana were exposed to agricultural recommended concentration (RC) and diluted concentration RC (1.10½, 1.10-1, 1.10-2, 1.10-3 ve 1.10-4) of Bacillus thuringiensis kurstaki to determine the letal concentration (LC50 and LC90). We found that the concentration LC50: 4th larvae (24, 48, 72 and 96 h) 3.541 (3.339-4.783) mg/ml, 3.012 (2.815-3.269) mg/ml, 2.438 (2.224-2.639) mg/ml and 1.892 (1.711-2.059) mg/ml; 5th larvae (24, 48, 72 and 96 h) 3.892 (3.495-6.730) mg/ml, 3.226 (2.960-3.661) mg/ml, 2.442 (2.150-2.764) mg/ml and 1.577 (0.682-2.218) mg/ml; Prepupa stage (24, 48, 72 and 96 h) 1.908 (1.665-2.132) mg/ml, 1.690 (1.461-1.901) mg/ml, 1.425 (1.204-1.630) mg/ml and 1.373 (1.161-1.575) mg/ml; Pupae stage (9. day and 12. day) 1.819 (0.920-2.491) mg/ml and 1.890 (1.599-2.156) mg/ml respectively. We found that the concentration LC90; 4th larvae (24, 48, 72 and 96 h) 4.108 (3.684-7.138) mg/ml, 4.045 (3.675-4.789) mg/ml, 3.516 (3.240-3.944) mg/ml and 2.541 (2.348-2.823) mg/ml; 5th larvae (24, 48, 72 and 96 h) 4.794 (4.027-10.751) mg/ml, 4.582 (4.027-5.775) mg/ml, 4.223 (3.708-5.121) mg/ml and 2.834 (2.197-4.677) mg/ml; Prepupa stage (24, 48, 72 and 96 h) 3.150 (2.857-3.571) mg/ml, 2.756 (2.500-3.112) mg/ml, 2.365 (2.117-2.717) mg/ml ve 2.249 (2.005-2.603) mg/ml; Pupae stage (9. day and 12. day) 3.114 (2.452-5.205) mg/ml and 3.122 (2.785-3.643) mg/ml respectively. The diluted concentrations of B. thuringiensis kurstaki insecticide according to the application dose are important for the natural cycle and continuity of parasitoid insects that provide balance for natural life. Therefore, this study may contribute new data to be used in Integrated Pest Management (IPM). The main reason for choosing this topic is to try to minimize the excessive and unconscious use of pesticides against pests.