Dr. Smitley works closely with the turfgrass, nursery and floriculture industries on identifying and solving insect pest problems, including best management practices for growers and landscapers. Basic and applied research is followed with extension recommendations for growers. In 1991, Dr. Smitley worked with Dr. Bauer to introduce Entomophaga maimaiga, a natural fungal pathogen of gypsy moth, into Michigan. E. maimaiga is now widespread throughout the state and forest defoliation due to gypsy is less than 1/10th of what it was in the early 1990’s. In the last 10 years, research on emerald borer led to the development of new management strategies, including the most widely used treatment for landscape trees: trunk injection with emamectin benzoate (TREEäge). Also, a series of field trials over the last 8 years led to a recent publication that explains how to use imidacloprid as a basal soil drench to reliably protect trees from emerald ash borer. This gives homeowners an option for treating their own trees with products available at local garden centers. Dr. Smitley introduced Ovavesicula popilliae, a natural pathogen of Japanese beetle, into Michigan in 2001 to help suppress populations of Japanese beetle. After 10 years, populations of Japanese beetle were lower and turf injury caused by Japanese beetle grubs was much less where O. popilliae was introduced.
At this time, the Smitley lab is working with the greenhouse and nursery industries to develop best management strategies for growing annuals, perennials, trees and shrubs that will be safe for pollinators after they are purchased and planted. Research is also continuing on the long-term impact of O. popilliae on Japanese beetle, including the distribution of infected beetles to areas where O. popilliae is not yet established.
Current assignment: Teaching 15% | Research 35% | Extension 50%
I teach ENT 364, Turfgrass Entomology, each fall semester to a class of 20 to 30 students, consisting mostly of Turf Management students in the 2-year or 4-year program. For six years I also taught a similar class at Sichuan Agricultural University in Ya'an, China, as part of the MSU Sino-American Turfgrass Management program. The turfgrass entomology class focuses on the identification and management of the most important turfgrass insect pests. There is one 2.5 hour lab and two lectures each week. Students have an exam every other week, make a collection of at least 70 species of insects, complete a laboratory practical, and a final exam. Objectives for the class are for all students to be able to sight identify the most important turfgrass pests and beneficials, be able to discuss practical management options, and to write a scouting and pest management plant, including a budget for the golf course, lawn care company, or sports complex where they work. An additional objective is to teach students about graduate school options, including how to apply to graduate schools and how to apply for teaching or research assistantships.
In 2014 I began an intensive research program to develop pest management programs for nursery and greenhouse growers that will allow them to produce high quality plants that will also be safe for pollinators after the plants are purchased and planted in the yard and garden. Experiments with colonies of bumble bees are used to validate the safety of pest management practices being tested. In 2014, grants were received from the Michigan Floriculture Growers Council, Project GREEEN, MDARD Hort Fund, Horticultural Research Institute and from the Specialty Crops Block Grant program to address this issue. Another grant proposal to the Horticultural Research Institute is still pending. In 1999 and 2000 I introduced a recently discovered microsporidean pathogen of Japanese beetle, Ovavesicula popilliae, into Michigan. With fifteen years of research and several scientific journal publications I have documented that if O. popilliae is introduced to one location on a golf course it will spread rapidly to throughout the entire golf course within 5 years, will double the winter mortality of Japanese beetle larvae from 25% to 50%, and will reduce the fecundity of females. Research is continuing on the long-term impact of O. popilliae on Japanese beetle. IR-4 and funding from industry has assisted in the testing and development of more efficacious and selective pest management products for the turfgrass, nursery and greenhouse industries.
I am working with a team of researchers and extension educators to address the neonicotinoid-pollinator crisis experienced by nursery and greenhouse growers, both at the state and national level. A series of educational articles were published as MSUE news articles or magazine articles. Within Michigan, our Extension floriculture team and Extension nursery team have conducted a series of workshops for greenhouse and nursery growers on how to produce high quality plants that will be safe to pollinators after they are sold and planted. Other Extension team programs in which I have played a role in the last 5 years, at state, regional or national levels, include 'protecting ash trees from emerald ash borer', 'management of European crane fly’, ‘management of resistant whitefly’, 'how to switch to biological control in greenhouses', 'safe suppression of ant mounding on golf course tees and greens', and development of 'smart lawns' recommendations for the 'smart gardening' program.
- Protecting pollinators on ornamental plants
- Long-term biological control of Japanese beetle
- Development of new pest management strategy
- 1999 - Present - Professor, Dept. of Entomology, Michigan State University
- 1993-1999 - Associate Professor, Dept. of Entomology, Michigan State University
- 1985-1993 - Assistant Professor, Dept of Entomology, Michigan State University
- Smitley, David R., Daniel A. Herms, and Terrance W. Davis. 2015. Efficacy of soil-applied neonicotinoid insecticides for long-term protection against emerald ash borer (Coleoptera: Buprestidae). J. Econ. Entomol. 109: 1 – 10.
- Smitley, D.R. 2012. European chafer. Pp. 33 – 35 In Handbook of Turfgrass Insect Pests, Entomological Society of America, Lanham, Md.
- Smitley, D. R., Jo, Y. and I. Hudson. 2011. Association of Ovavesicula popilliae (Microsporida: Ovavesiculidae) with winter mortality of larvae and reduced fecundity of female Japanese beetles (Coleoptera: Scarabaeidae). Environ. Entomol. 40: 589 – 596.
- Doccola, J.J., D.R. Smitley, T.W. Davis, J.J. Aiken, and P.M. Wild. 2011. Tree wound responses following systemic insecticide trunk injection treatments in green ash (Fraxinus pennsylvanica Marsh.) as determined by destructive autopsy. Arbor. & Urban Forestry 37(1): 6–12.
- Smitley, D.R., J.J. Doccola and D.L. Cox. 2010. Multiple-year protection of ash trees from emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), with a single trunk injection of emamectin benzoate and single-year protection with an imidacloprid basal drench. Arboriculture & Urban Forestry 36: 206 - 211.
- Smitley, D.R., E.J. Rebek, R.N. Royalty, T.W. Davis and K.F. Newhouse. 2010. Protection of individual ash trees from emerald ash borer (Coleoptera: Buprestidae) with basal soil applications of imidacloprid. J. Econ. Entomology 103: 119 – 126.
- Rebek, Eric J., Daniel A. Herms, and David R. Smitley. 2008. Interspecific variation in resistance to emerald ash borer (Coleoptera: Buprestidae) among North American and Asian ash (Fraxinus spp.). Environ. Entomol. 37: 242 – 246.