Evidence-Based Monitoring of Prodiplosis longifila in Foliage Crops: Damage, Economic Impact, Trapping Tools, and...

Prodiplosis longifila (Diptera: Cecidomyiidae) has recently emerged as a major threat in foliage production systems in Colombia; however, key aspects of its damage, population dynamics, and monitoring remain poorly understood. This study addresses these knowledge gaps by evaluating phenological stages, injury patterns, economic impact, and spatio-temporal population dynamics of P. longifila in the foliage crops Ruscus aculeatus and Cocculus laurifolius under open-field and greenhouse conditions in commercial production areas. Monitoring efficiency was assessed using traps of different colors and heights to optimize sampling protocols and improve understanding of adult behavior. Field data were complemented with spatio-temporal analyses to characterize dispersal patterns and aggregation processes within production systems. Damage was detected across all three larval instars, with the most severe injury occurring during the first and second instars, resulting in significant reductions in foliage quality and marketability. Productivity losses reached 53% in R. aculeatus and 29% in C. laurifolius, accompanied by sharp declines in extra-quality stems and maximum income losses of 79% and 56%, respectively. Adults exhibited a consistent preference for black, white, and yellow traps placed 10-30 cm above host plants, providing practical guidelines for improving monitoring accuracy. Kernel density analyses revealed that populations initially aggregated along greenhouse borders and subsequently dispersed toward the interior, generating internal hotspots associated with localized environmental and microclimatic conditions. Adult activity was predominantly crepuscular, with clear peaks between 21:00-22:00 h and 03:00-04:00 h. This study provides the first integrated assessment of P. longifila in foliage crops, generating critical ecological and applied information to support improved monitoring, early detection, and targeted management strategies for this emerging pest in ornamental foliage production systems.