Parasitism and predation rates of natural-laid eggs and sentinel eggs masses of brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), on Georgia blueberries

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) known as BMSB is an invasive pest of blueberries, a major economic crop commodity in Georgia. Lab-reared sentinel BMSB egg masses are used as a monitoring method to determine seasonal biological control impacts but can underestimate those impacts. The objective of this project is to examine the parasitism and predation rates of biological control agents on sentinel BMSB and naturally-laid egg masses on rabbiteye blueberry bushes. Fresh sentinel egg masses were hanged on blueberry bushes under shady leaves once in June and July. BMSB adults were released into 8 enclosures covering unmanaged blueberry bushes and were allowed to naturally lay eggs once in June and twice in July. Both types of BMSB eggs were then allowed to be exposed to natural enemies in the blueberry field for 3 days. Naturally-laid egg masses had higher predation rates in July, parasitism rates in June, and mortality rates in July. Fresh sentinel egg masses had higher predation rates than parasitism rates for both months and had higher predation and mortality rates in July. Naturally-laid egg masses had significantly higher predation rates in July and parasitism rates in June than sentinel egg masses. Overall, naturally-laid egg masses had significantly higher predation and mortality rates than fresh sentinel egg masses. Sentinel eggs can underestimate the rates of predation and parasitism in blueberry systems depending on the time of year. Therefore, future studies should explore this topic in relation to different crop systems.