Biological Control

 of Elm Pests

How do we control damaging insects that eat desirable plants, such as elm trees? Biological control is a helpful tactic for controlling an undesired pest using other organisms to consume the pest. Biological control allows us to suppress a pest's population using its "natural enemies" without spraying chemical insecticides, which are expensive, drift into non-target areas, harm pollinators and other beneficial insects, and cause unforseen outbreaks of other pests. 

My research identified insect natural enemies of two pests of elm trees, elm leaf beetle (Xanthogaleruca luteola) and elm flea weevil (Orchestes steppensis). By identifying and documenting the bugs that eat elm pests, we are one step closer to using sustainable biological control and keeping these insects at manageable levels.


Buenrostro J, Cooke C, Hufbauer R (2023). New records of elm leaf beetle (Xanthogaleruca luteola) parasitoids in Colorado with notes on predators. Southwestern Entomologist, 47(4). 

Buenrostro J, Cooke C, Hufbauer R. Complex of parasitoids reared from the introduced elm pest Orchestes steppensis in western North America (manuscript in progress)


Buenrostro J, Cooke C, Hufbauer R (2022). The heat is on! Elm pests and their parasitoids have unique relationships with urban habitats. Entomological Society of America, Joint Annual Meeting. Vancouver, BC

Buenrostro J (2022). It's a bug-eat-bug world: can we use insects to control damaging elm pests? CSU Speaks, an event by CSU Science in Action. New Belgium Brewing, Fort Collins

New state records

By rearing elm leaf beetle eggs and larvae, we found that the parasitoids Oomyzus gallerucae (Eulophidae) and Erynniopsis antennata (Tachinidae) are present in Colorado. This is the first time these parasitoids have been documented in the state! Future research efforts might focus on how to increase their control against elm leaf beetle in the state and region.

Erynniopsis antennata, a parasitoid of elm leaf beetle larvae. Jack Kelly Clark, University of California - Statewide IPM Program,

Oomyzus gallerucae, a parasitoid of elm leaf beetle eggs. Bruno Lavoue,

Updated Predator Records

We also identified six species of elm leaf beetle predators, several of which are newly documented to consume elm leaf beetle. A) Harmonia axyridis (Coleoptera: Coccinellidae), B) Phyllobaenus sp. (Coleoptera: Cleridae), C) Parasteatoda tepidariorum (Araneae: Theridiidae), D) Pogonomyrmex occidentalis (Hymenoptera: Formicidae), E) Forficula auricularia (Dermaptera: Forficulidae), and F) Podisus placidus (Hemiptera: Pentatomidae). Future research efforts might focus on quantifying the levels of contol provided by predator natural enemies against elm leaf beetle in the state and region.