Rachael A. Sitz
Research Plant Pathologist
1221 South Main Street
Contact Rachael A. Sitz
My research focuses on microbial plant pathogens and their associations with insects. Specifically, my work on a bacterial pathogen better characterizes drippy blight disease of red oaks. In this system, I assess insect dissemination of the bacterium and integrate experimental observations of disease symptomology and the life history / biology of a kermes scale insect to provide management recommendations. I am also interested in understanding if host trees from different geographical regions have resistance to the fungal causal agent of thousand cankers disease inflicting black walnuts. Moving forward, I will look at gene expression and pathogenicity mechanisms in fungal pathogens.
I am curious about many aspects of forest health, especially (1) determining epidemiology and management for emergent and invasive diseases, (2) explaining how microbes interact with other microbial or insect communities to produce disease, and (3) assessing the mechanisms fungi use to cause disease and develop relationships with insect vectors.
My past research experiences give me a background in both applied entomology and plant pathology. Some of my past research objectives include:
1) Understanding if the pathogen Geosmithia morbida interacts synergistically with Fusarium solani to escalate plant disease.
2) Determining if distinct genetic groups of Geosmithia morbida explain disease severity.
3) Documenting neonicotinoid resistance in European elm scale, and determining alternative chemical control methods for the European elm scale.
4) Predicting whether the thermal tolerance of the walnut twig beetle impacts the climate regimes it could withstand.
5) Providing information on the best management practices for thousand cankers disease infected trees and felled logs to prevent the spread of disease.
6) Evaluating switchgrass cultivars for susceptibility to aphid pests.
Why This Research is Important
Today’s forests are experiencing increasingly rapid environmental change and frequent introductions of invasive species. Forest health continues to decline in response to both abiotic and biotic environmental stressors. These stressors predispose trees and, as a result, can drive disease development and spread. Therefore, understanding the biological agents impacting our forests is critical. Information on disease causal agents can be used to increase tree resiliency and ultimately maintain the positive environmental and health benefits of both urban and natural forests.
- Colorado State University, Ph.D. Candidate Bioagricultural Sciences and Pest Management with an emphasis in Plant Pathology 2017
- Colorado State University, M.S. Bioagricultural Sciences and Pest Management with an emphasis in Entomology 2013
- University of Nebraska-Lincoln, Lincoln, B.S. Plant Biology and Insect Science with a minor in Biology 2011
- American Phytopathological Society Of America, Member (2017 - )
- Walnut Council, Member (2012 - 2014)
- Entomological Society of America, Member (2011 - )
Awards & Recognition
- J. H. Comstock Graduate Student Award, 2018
An award given by the Entomological Society of America's North Central Branch.
- Certificate of Merit – RMRS , 2017
For outstanding performance as a pathways Intern (Plant Pathology) in support of the Forest and Woodland Ecosystems Science Program at Rocky Mountain Research Station
- Hawksworth Memorial Award for Tree Pest Management, 2016
Colorado State University Department of Bioagricultural Sciences and Pest Management Graduate Student Award
- Sitz, Rachael A.; Aquino, M. Vincent; Tisserat, A. Ned; Cranshaw, S. Whitney; Stewart, Jane E. 2019. Insects visiting drippy blight diseased red oak leaves are contaminated with the pathogenic bacterium Lonsdalea quercina.
- Sitz, Rachael A.; Zerillo, Marcelo M.; Snelling, Jacob ; Caballero, Jorge Ibarra; Alexander, Kathleen ; Nash, Kendra ; Tisserat, Ned A.; Cranshaw, Whitney S.; Stewart, Jane E. 2018. Drippy blight, a disease of red oaks in Colorado, U.S., produced from the combined effect of the scale insect Allokermes galliformis and the bacterium Lonsdalea quercina subsp. quercina.
- Sitz, Rachel A.; Cranshaw, Whitney S. 2018. Life history of Allokermes galliformis (Hemiptera: Kermesidae) in Colorado.
- Sitz, R. ; Utley, C. ; Hall, A. ; Tisserat, N. ; Cranshaw, W. . 2017. Trapping the walnut twig beetle to determine flight patterns in Colorado.
|Drippy blight: A new disease complex of red oak|
Disease complexes, the result of insects and plant pathogens interacting to compromise their plant hosts, are becoming increasingly common world ...