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Dr. Joseph C. Neal —
Recent and Current Research Projects

Biological and natural products for weed control. Recent research has focused on evaluating Phoma macrostoma, MBI-005 (thaxtomin) and Fe-HEDTA (Fiesta) for weed control in turfgrass and landscape plants. Results have been presented at the 2013 WSSA annual conference (link to abstract) and the 2013 International Bioherbicide Group Workshop (link to abstract). Research is currently being expanded through a Master of Science project by Mr. Joseph Wolfe

An assessement protocol for Invasive species currently sold in the nursery trade was developed by Ms. Clara Englert as part of her M.S. project. This project was funded by a grant from the North Carolina Nursery and Landscape Association. Dr. Thomas Ranney was co-advisor on this project.( Links to the assessment protocol and Thesis).

Longevity of weed control in container nursery crops. Using bioassay methods we have shown that preemergence herbicides applied to nursery crops provide only 4 to 6 weeks control of most weeds. Typical re-application intervals of 8 to 12 weeks will allow weeds to emerge and establish. Recent research suggests that the herbicide indaziflam remains active in container substrates longer that competing products. This research has been supported by grants from the Horticultural Research Institute, BASF Corporation, Valent Corporation, Bayer Crop Science and OHP. Publications: trifluralin dissipation; Freehand residual control.

Ecology and management of Japanese Stiltgrass (Microstegium vimineum). Studies included evaluations of preemergence and postemergence herbicide efficacy, seed dormancy and germination requirements, and native plant community responses to Japanese stiltgrass control options. Project conducted as a Ph.D. project by Dr. Caren Judge. Summary of field results presented at the 2005 Weed Science Society of America annual conference. Click here for the powerpoint presentation. Dissertation is available here.

Control options for recently introduced weeds in nursery crops. A collaborative project with Dr. Jeff Derr, Virginia Tech University. The efficacy of herbicides labeled for preemergence weed control in container nurseries was compared on several species of newly introduced weeds. This project is supported by a grant from the Horticultural Research Institute. publication: doveweed control in containers

Dodder host specificity in bedding plants. Currently few control options are available to landscape managers who have landscape beds infested with dodder (Cuscuta spp.). This study identified several bedding plant species that were not preferred hosts of dodder, providing a potential management strategy for this parasitic weed. Project was supported in 2005 by a grant from the NC Extension IPM Program. Recent results presented at the Southern Nursery Association Research Conference -- click here for a powerpoint presentation.

Herbicide Safety on Nursery Crops and Landscape Ornamentals. Rearch collaborations with the USDA-IR-4 program and product manufacturers continues to expand herbicide registrations and register new herbicides for weed control in ornamentals. Recent foci of the program have been the development of flumioxazin (Broadstar and SureGuard) and dimethenamid-p (Tower) for weed control in nursery crops; herbicide safety in herbaceous perennials; herbicide safety in ferns; and safety of postemergence herbicides for nutsedge and broadleaf weed control in ornamentals. Recent research has included phenoxy herbicides affects on seedhead formation in ornamental grasses; Tower herbicide potential for over the top use in woody ornamentals; safety and efficacy of natural products for liverwort control, herbicide safety on herbacous ornamentals.

Taxonomy and management of common weeds of nursery crops. Several projects include a comparison of Ranunculus ficaria sub species distribution and spread in the U.S.(manuscript in review); and a taxonomic study of species of Cardamine species found in container nursery crops. Both projects conducted by Dr.. Angela Post (currently on the faculty of Oklahom State University).

Extension Program

Weed management systems for nursery crops, landscapes, and Christmas trees. Programs emphasize in-service training of Extension field faculty and resource development.

Books and Bulletins:

Horticulture Information Leaflets:

  • Greenhouse weed control -- HIL 570
  • Weed control in color beds -- HIL 644
  • Weed control in conifer seedbeds and landscape beds -- HIL 449
  • Non-selective Herbicides for Nursery and Landscapes -- HIL 648
  • Controlling Sedges in Landscape Plantings -- HIL 647
  • Japanese Stiltgrass control -- HIL 905

Complete Publication List

Selected Publications

  1. Zhou, T. and J. C. Neal. 1995. Annual bluegrass (Poa annua) control with Xanthomonas campestris pv. poannua in New York State. Weed Technology 9:173-177.
  2. Uva, R. H., J. C. Neal and J. M. DiTomaso. 1997. Weeds of the Northeast. Cornell University Press, New York. 396pp.
  3. Neal, J. C., J. F. Derr, A. F. Senesac and W. A. Skroch, 1999. Weed Control Suggestions for Christmas Trees, Woody Ornamentals, and Flowers. NC Cooperative Extension publication AG-427.
  4. Neal, J. C. 2000. Weed control in woody liner production. Proceedings of the International Plant Propagator's Soc. 50:528-531.
  5. Krings, A. and J. C. Neal. 2001. A Scutellaria (Lamiaceae) new to North Carolina and a key to the small-flowered Carolina congeners. SIDA 19(3):735-739.
  6. Judge, C. A., J. C. Neal, and R. B. Leidy. 2003. Trifluralin (Preen) dissipation from the surface layer of a soilless plant growth substrate. Journal of Environmental Horticulture 21:216-222 pdf
  7. Judge, C. A., J. C. Neal, and J. B. Weber. 2004. Dose and concentration responses of common nursery weeds to Gallery, Surflan and Treflan. Journal of Environmental Horticulture 22:106-112. pdf
  8. Judge, C. A., J. C. Neal. and J.F. Derr. 2005. Response of Japanese Stiltgrass (Microstegium vimineum) to application timing, rate, and frequency of postemergence herbicides. Weed Technol. 19:912-917. pdf
  9. Neal, J. C. and J. F. Derr. 2005. Weeds of container nurseries in the United States. NC Nurserymen’s Assoc. 16 p.
  10. Judge,C. A. and J. C. Neal. 2006. Early postemergence control of nursery weeds with Broadstar, OH2 and Snapshot TG. J. Environ. Hort 24(2):105-108 pdf
  11. Post, A. R., A. Krings, W. Wall, and J. C. Neal. 2009. Introduced lesser celandine (Ranunculus ficaria, Ranunculaceae) and its putative subspecies in the United States: a morphometric analysis. J. Bot. Res. Inst. Texas (formerly SIDA) 3(1):193-209 pdf
  12. Post, A.R., J. C. Neal, A. Krings, B. R. Sosinski, and Q. Xiang. 2009. New Zealand bittercress (Cardamine corymbosa; Brassicaceae): new to the United States. Weed Technol. 23:604-607. pdf
  13. Walker, L.H., J.C. Neal and J.Derr. 2010. Preemergence control of doveweed (Murdannia nudiflora) in container grown nursery crops. J. Environ. Hort. 28(1):8-12 pdf

International Experience

Participant in the International Bioherbicide Group


  • Screening rhizobacteria for selective suppression of annual ryegrass in canola and wheat. Hosted by Dr. Gavin Ash, Charles Sturt University, Wagga Wagga, NSW, Australia.
  • Weed management practices in Australian nurseries. Hosted by Dr. Ian Gordon, Univ. of Queensland, Gatton, Queensland, Australia