Biology and functional response of Predator orius Vicinus (Ribaut) (Hemiptera: Anthocoridae) on Tetranychus urticae Koch (Acarina:Tetranychidae)

Tetranychus urticae is a widespread polyphagous pest in greenhouse vegetable cultivation and shows serious resistance to acaricides. Due to insecticide residues in foodstuffs, negative effects on human and animal health, environmental pollution and high pesticide costs, biological control have been started to be preferred which is more economical and sustainable. Within the scope of biological control, studies of biological characteristics and the preying capacity of natural enemies on pests are of great importance. In this study, the functional response of O. vicinus to different stages of T. urticae at densities of 2, 4, 8, 16, 32, 64, and 128 were investigated. Our studies were carried out in air-conditioning rooms with 26±1ºC temperature, %60±10 relative humidity and 16:8 light-dark conditions. When O. vicinus was fed with the adult T. urticae, egg and nymph development times, nymph survival rates, adult reproductive capacities and adult life spans were determined separately. As a result of the study, egg hatching time of O. vicinus was determined as 4.07 days and total nymph development time was 17.6 days. Nymph survival rate was determined as 75.7%. The average number of eggs laid per female was 31.28, the average lifespan of females was 15.3 days, while the average lifespan of males was detected as 12.50 days. According to life table parameters, it was determined that preoviposition time (APOP) was 4.39 days, total preoviposition time (TPOP) was 21.85 days and oviposition time was 7.2 days. The intrinsic rate of incresae (r) was 0.095 days-1, finite rate of increase () was 1.1 days-1, net reproductive rate (R0) was 12.04 eggs/offspring, and the mean generation time (T) was 26 days. As a result of the functional response results, it was observed that O. vicinus showed a type III functional response to T. urticae eggs, and a type II functionalresponse to all other stages. According to the results of the life table parameters, it is considered that the effectiveness of O. vicinus against T. urticae is moderate depending on the net reproductive power. According to the results obtained in the study, O. vicinus can be an effective biological control agent in the biological control of T. urticae, as O. vicinus completes its life cycle and can maintain its population. KEYWORDS: Biological control, Functional response, Life table, Orius vicinus, Tetranychus urticae