Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Systematic Entomology Laboratory » Research » Publications at this Location » Publication #420496
Research Project: Systematics of Beetles, Flies, Moths and Wasps with an Emphasis on Agricultural Pests, Invasive Species, Biological Control Agents, and Food Security

Location: Systematic Entomology Laboratory

Title: Anatomy of a forest pest outbreak oak shothole leafminer, damage, and host susceptibilities

Author
item QUESADA, CARLOS - West Virginia University
item LARCENAIRE, CRAIG - Forest Service (FS)
item Scheffer, Sonja
item MCGILL, DAVE - West Virginia University
item TURCOTTE, RICHARD - Forest Service (FS)

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2025
Publication Date: 3/13/2025
Citation: Quesada, C., Larcenaire, C., Scheffer, S.J., Mcgill, D., Turcotte, R. 2025. Anatomy of a forest pest outbreak oak shothole leafminer, damage, and host susceptibilities. Journal of Economic Entomology. 118(2):770-779. https://doi.org/10.1093/jee/toaf045.
DOI: https://doi.org/10.1093/jee/toaf045

Interpretive Summary: The oak shothole leafminer is important because oaks provide invaluable ecological services in forests and urban settings. The oak shothole leafminer causes conspicuous damage to oak leaves, and during outbreaks, results in leaf drop that negatively affects tree health in addition to being unsightly and disturbing to homeowners. This study investigated the levels and cause of leaf damage during the mid-Atlantic 2019/2020 outbreak. Patterns of adult leafminer abundances before and after the outbreak indicate that data from insect traps can be used to signal upcoming outbreaks. This work will be of interest to forest scientists, ecologists, extension agents, and entomologists.

Technical Abstract: Understanding the impact of the shothole leafminer Japanagromyza viridula (Coquillett) on oaks is important because oaks provide invaluable ecological services in forests and urban settings. In 019 and 2020, shothole leafminers caused high levels of damage to oak trees in several states in the mid-Atlantic region. The objectives of this study were to compare oak shothole leafminer damage on northern red oak (Quercus rubra), chestnut oak (Q.montana), white oak (Q. alba), scarlet oaks (Quercus coccinea) and to fill critical knowledge gaps of oak shothole leafminer biology. Chestnut oak was consistently the oak species with the least leaf area reduction and foliage transparency. The injuries on chestnut oak leaves were primarily small and uniform holes (“shotholes”) due to this leafminer. In contrast, northern red oak and scarlet oaks showed high susceptibility. Damaged leaves of these species frequently were deformed or incomplete, and the shotholes varied in size, resulting in greater leaf area reduction. Experiments showed that the conspicuous shothole damage caused by this leafminer is related puntucring by the female flies into leaves of young buds. Oak shothole leafminer is a native cryptic species and visual outbreaks will only be noticed when its emergence coincides with oak bud and early leaf development. Leaf area reduction, percent damaged leaves, foliage transparency, and crown dieback were calculated to compare damage experienced by the different oak species. Emergence and Malaise traps were used to assess adult population sizes.