Efficacy and persistence of native entomopathogenic nematodes against Capnodis tenebrionis in peach (Prunus persica) orchard in Turkey

Entomopathogenic nematodes (EPN) have an important potential in the biological control of agricultural soil pests. Efficacy and persistence of native EPN species from Turkey were investigated against Capnodis tenebrionis (L.) (Coleoptera: Buprestidae) larvae with different irrigation methods in a peach (Prunus persica L. Rosaceae) orchard for two years. Four native EPN species, Steinernema carpocapsae Weiser (Nematoda: Steinernematidae), S. feltiae Filipjev (Nematoda: Steinernematidae), S. affine Bovien (Nematoda: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Nematoda: Heterorhabditidae), were applied to soil via drip irrigation, surface irrigation and soil injection methods to determine the mortalities of C. tenebrionis neonate larvae caused by these species naturally. In all applications, EPNs were applied as 50 IJs/cm(2). Mortalities were calculated on the 1st, 3rd, 5th and 7th days of the experiment. The results of the study indicated that on the first day of surface irrigation, the highest mortality was found in H. bacteriophora with 87.5% and the lowest mortality was found in S. feltiae with 16.6% in 2018. In 2019, however, the highest mortality on the first day was from S. affine with 91% and the lowest was from both S. carpocapsae and S. feltiae with 33.3%. EPN persistence in soil was found to be 90 days in 2018, while it was 150 days in 2019. In all EPN treatments, 100% mortality was reached on the fifth day indicating all EPN treatments were highly effective. Based on the study results, it can be concluded that farmers might be able to control C. tenebrionis damage by using EPN in their regular irrigation calendar.