A systems approach to mitigate pest risk for market access of cut flowers exported from Hawaii

The floriculture and nursery industry is a key contributor to Hawaii's economy, with ornamental crop exports, particularly cut flowers, accounting for a significant portion of sales. However, pest-related shipment rejections have increasingly threatened market access. As a first step to develop an effective systems approach for maintaining market access, we analyzed California interception records from 2012 to 2016, which revealed 582 cut flower shipment interceptions from 92 Hawaiian growers and shippers, with rejections primarily due to ants, aphids, mealybugs, and scale insects for non-orchid cut flowers (eg ginger and heliconia) and thrips for cut orchid flowers (eg Dendrobium). For targeted trials of ginger and heliconia, the effect of sequential pre-harvest (systemic insecticide spraying and ant baiting) and postharvest treatments (washing, hot water treatment, and second washing) were evaluated under commercial conditions. While individual treatments alone did not achieve complete disinfestation of ginger and heliconia, combining them as a systems approach led to zero detectable infestation across 8 harvests during the second year of the study, indicating this may be a feasible phytosanitary strategy for Hawaii-grown cut flowers. In contrast, for Dendrobium orchids with limited postharvest treatment options, pre-harvest insecticide programs were ineffective for managing thrips, with 30% of Dendrobium flowers and 70% of the flower sprays remaining infested post-insecticide treatment, highlighting the need for improved thrips management and the potential for integrating with postharvest fumigation. Overall, our results demonstrate the potential of systems approach in reducing pest interceptions and supporting continued access of Hawaii-grown cut flowers to US mainland and international markets.