The Preliminary Study on the Biology of An Invasive Species, Halyomorpha halys (Hemiptera: Pentatomidae) in Northwest Türkiye

The Brown marmorated stink bug (BMSB) [Halyomorpha halys (Hemiptera: Pentatomidae)] is a polyphagous pest causing significant damage to approximately 300 crops, such as  nuts, vegetables, and ornamentals. In 2017, the BMSB was discovered for the first time in Türkiye. There is currently no published data available on the biology of the pest in Türkiye.  This preliminary study was carried out in Sakarya province, where the BMSB has observed a low population since 2021. In this study, some biological parameters such as voltinism, mortality rates, egg hatching rates, and egg-adult developmental times of the 1st and 2nd generations of the insect populations were determined. The study was carried out under semi-field conditions and laboratory. Considering the BMSB's minimum temperature threshold, which has yet to be determined in Turkey, the accumulation of degree days was calculated using the references to four possible thresholds (DD12, 12.5, 13, 13.5) and was determined to be between 536.91 - 608.69 DD.  The average egg-adult developmental time was 47.85 days for the 1st generation at naturally fluctuating temperatures and 47.13 days for the 2nd generation under laboratory conditions at 25 ֯C. The hatching rate of egg masses was determined to 90.63% in the 1st generation and 57.75% in the 2nd generation. Total mortality in the first generation was 22.97% and 90.24% in the second generation.  It was revealed  that the insect could produce two generations in Türkiye, but the number of egg-producing adults and eggs laid in the second generation was significantly lower than that in the first. This preliminary study was carried out with a limited number of samples due to the initial infesting in the region and,  therefore more comprehensive research is needed to reveal the the biology of BMSB in the country.