Stevan Z. Knezevic



Stevan Z. Knezevic


Area of Expertise: Plant Physiology, Weed, and Production Systems

B. S., Plant Protection, University of Belgrade, 1986

M. S., Crop Science (Weed Science), University of Guelph, 1993

Ph.D., Agronomy (Weed Science), Kansas State University, 1997

Area of Focus

Integrated Weed Management

Research Interests

The objective of my research program is to develop weed control strategies based on a multidisciplinary approach that builds bridges among scientific disciplines, especially between weed/crop ecology and herbicide technology. A single weed control measure is not feasible due to the number of different weed species and their highly variable life cycles. My program, therefore, advocates a combination of weed control methods (the use of many "little hammers"). We conduct weed control studies in field crops (conventional and organic), rangeland, pasture and riparian settings. Over the last 15 years I have developed nationally and internationally recognized expertise on the following 3 concepts:

  1. Critical Period of Weed Control (CTWC) and data analysis: Our manuscript on CPWC provided a standardized procedure for this type of studies (Knezevic et al. 2002. Critical period of weed control: the concept and data analysis. Weed Sci. 50: 773-786). So far we had published 9 manuscripts related to this concept with the work of 3 of my graduate students.
  2. Dose Response Studies and data analysis: Our manuscript provided a standard procedure (e.g. recipe) for this type of studies (Knezevic et al. 2007. Utilizing R software package for dose-response studies: the concept and data analysis. Weed Technol. 21:840-848). This manuscript was the MOST READ and MOST CITED manuscript from 2001-2011. So far we have published over 10 manuscripts that utilized this concept in handling data analysis. We also utilize this concept routinely in herbicide evaluation trials and flaming weeding studies.
  3. Weed Flaming and data analysis: Our flame weeding studies were conducted in 7 agronomic crops, primarily corn (field corn, popcorn and sweet corn), sorghum, sunflower, soybean and winter wheat. We are also interested to expend to other crops. So far we published about 20 manuscripts.

Courses Taught

Honors and Awards

  • The MOST READ and MOST CITED manuscript in last 10 years (2001-2011) in Weed Technology Journal (Title: Utilizing R Software Package for Dose-Response Studies: The Concept and Data Analysis" )
  • Internet Tool for Weed Control (Web Version of Nebraska Weed Guide), American Society of Agronomy, 2011
  • Honorable mention at NCWSS, program with largest number of papers at NCWSS in WI, with 18 papers, 2011
  • Featured Article for Weed Technology Journal in 2010. Title: Growth Stage-Influenced Differential Response of Foxtail and Pigweed Species to Broadcast Flaming, featured article in November-2010.
  • Top Cited article for Weed Technology journal in 2009 (464 hits). (Title: Adjuvants Influenced Saflufenacil Efficacy on Fall-Emerging Weeds). It was also in the top 10 articles from 2005-2009.
  • Excellence in Team Programming, from University of Nebraska–Lincoln IANR for the "Skip Row Corn Team" team.
  • Best Extension Publication. Guide for Weed Management in Nebraska. American Soc. of Agronomy. 2006
  • Best paper (2nd place) published in the 2001 issue of the Weed Science J. 47:454-461. WSSA. 2001
  • Outstanding Young Scientist in Crop Protection, American Society of Agronomy, 2000.
  • Layman Research Award, IANR, University of Nebraska–Lincoln. 2000.

Student and Visitors Research Projects

( a ) Post Doctoral Research Associate:

  1. Dr. Avishek Datta, Vegetation control on sandbars along Missouri River (2008-2012)
  2. Dr. Rena Neha, Glyphosate and HPPD resistance (2012-present)

( b ) Ph. D. students:

  1. Janyce Woodard, Weed control and growth of buffer crops (2004-current-part time)
  2. Santiago Ulloa, Weed control with flaming (2006-2010)
  3. Ryan Rapp, Integrated management of common reed (2008-2012)
  4. Igor Elezovic, CTWC in sunflower (2009-present, U of Belgrade, Serbia)
  5. Robert Leskovsek, Common ragweed control (2008-2012, U of Maribor, Slovenia)
  6. Isa Kabenge, Energy fluxes of invasive species along the Platte River (2008-2011)
  7. Chris Bruening, Designing new flaming equipment (2010-present)
  8. Electra Kanellou, Vegetation control around historical sites (2012-present, Univ. of Athens, Greece)

( c ) M. S. students:

  1. Sean Evans, Critical period of weed control in corn (1999-2001)
  2. Shawn Hock, Competitive indices of weed species in soybean (2002-2005)
  3. Travis Gustafson, Weed-insect interactions on weed management (2003-2005)
  4. Katie Wrade (MAg), Field sandbur control in corn (2003-2005)
  5. Aaron Quinn, Predicting purple loosestrife infestations using GIS model (2004-2006)
  6. Chris Bruening, Designing new hood for crop and weed flaming (2007-2009)
  7. Brian Neilson, Flaming and Cultivation in Sunflower (2009-2012)
  8. Strahinja Stepanovic, Weed Control with Cultivation and Flaming (2011-present)
  9. Dejan Nedeljkovic, Control of glyphosate resistant Giant Ragweed (2010-present)

( d ) Undergraduate students:

  1. Christy McCoy, Velvetleaf control in Roundup-Ready soybean (WSC in 2001)
  2. Andre Domingues, Flaming methods for selected weed species (Brazil in 2007)
  3. Heverton Z. Teixeira , Corn response to flaming (Brazil in 2007)
  4. Pierre Marteau, Sunflower growth and duration of weed removal (France, 2008)
  5. Claudio Martins-Costa, Differential tolerance of corn types to flaming (Brazil in 2008)
  6. Jayme Netto, Wheat tolerance to broadcast flaming (Brazil in 2008)
  7. Brian Neilson, Sweet corn tolerance to flaming (University of Nebraska–Lincoln in 2009)
  8. Dustin Simpson. Weed control with flaming (University of Nebraska–Lincoln in 2009)
  9. Strahinja Stepanovic, Weed control with flaming in corn (Serbia, 2010)
  10. Dejan Nedeljkovic, Corn Tolerance to multiple flaming (Serbia, 2011)
  11. Ana Obradovic, Economics of flame weeding (Serbia, 2011)

( e ) Visiting Scientists and Scholars:

Visits that lasted from 1 to 6 months:

  1. Dr. Mario Lesnik (Slovenia), Dose response concept (2009)
  2. Dr. Goran Malidza (Serbia), Critical period of weed control in sunflower (2009)
  3. Dr. Marco Fontanelli (Italy), Weed control with flaming (2009)
  4. Mr. Sidnei Cavalieri (Brazil), Popcorn tolerance to nicosulfuron (2009)
  5. Igor Elezovic, (Serbia) CTWC in sunflower (2010)
  6. Robert Leskovsek (Slovenia), Common ragweed control (2010)
  7. Dr. Nihat Tursun (Turkey). Soybean tolerance to multiple flaming (2011)

Visits that lasted less than 1 month:

  1. Dr. Ibro Elezovic from Serbia in 2010, Weed control with flaming
  2. Dr. Peter Bleeker from Holland in 2009, Crop tolerance to flaming
  3. Dr. Mario Lesnik from Slovenia in 2008, Weed flaming
  4. Dr. Andrey Simoncic from Slovenia in 2008. Weed flaming
  5. Dr. Renan Aguero from Costa Rica in 2008, Weed control with flaming
  6. Dr. Ryohei Ueno from Japan in 2007, Dose response concept
  7. Dr. Toshihiro Ambe from Japan in 2007, Dose response concept
  8. Dr. Peter Sikkema from Canada in 2007, Dose response concept and data analysis
  9. Dr. Joashir Kaiser from Germany in 2007, Dose response concept
  10. Dr. Kenji Takama from Japan in 2006, Dose response concept
  11. Dr. Hasashi Honda from Japan in 2006, Dose response concept
  12. Dr. Milena Simic from Serbia in 2006, CTWR in sunflower
  13. Dr. Mirko Ivanovic from Serbia in 2006, Dose response concept
  14. Dr. Radivoje Jevtic, from Serbia in 2006 Dose response concept
  15. Dr. Nedeljko Latinovic from Montenegro in 2006, Dose response concept
  16. Dr. Nioki Oyamma from Japan in 2005, Dose response concept
  17. Dr. Yoshihiro Yamaji from Japan in 2005, Dose response concept
  18. Dr. Osamu Watanabe from Japan in 2005, Dose response concept
  19. Dr Yariv Keadr from Israel in 2004, Dose response concept
  20. Dr. Moshik Fish from Israel in 2004, Dose response concept

Extension Interests

  • To keep crop producers up to date with the current weed control issues.
  • To respond promptly and accurately to the regional needs and requests related to weed control and crop production.
  • To utilize various distance education tools in order to disseminate information to county educators, crop consultants, growers, and the public in general.


Extension Publications

  • Knezevic S. Z., A. Datta and R. Rapp. 2008. Common Reed. UNL-Extension Publication. EC-08-166.
  • Wilson R. and S. Z. Knezevic. 2007. Salt cedar. UNL-Extension Publication. EC-07-164.
  • Knezevic et al. 2005. Integrated management of eastern red cedar. UNL-Extension Publication. EC-05-186.
  • Knezevic S. Z. 2003. Purple loosestrife. UNL-Extension Publication. EC-03-176. Anderson B. E., Knezevic et al. 2003. Alfalfa in Nebraska. EC03-181.
  • Anderson B. E., Knezevic et al. 2003. Alfalfa in Nebraska. EC03-181.
  • Heckman N. L., Knezevic et al. 2002. Spotted and Diffuse Knapweed. UNL-Extension Publication. EC-02-173-S.
  • Knezevic S. Z. 2002. Use of herbicide tolerant crops as a component of an integrated weed management program. NebGuide, UNL-Extension Publication. G02-148-A.
  • Hunt T. and S. Z. Knezevic. 2002. Monitoring procedures for Galerucella beetles to control purple loosestrife. Extension Circular. UNL-Extension Publication. EC02-175.
  • Knezevic S. Z. and D. Smith. 2001. Rearing and releasing Galerucella beetles to control purple loosestrife. NebGuide. UNL-Extension Publication. G01-1436-A.
  • Eghball B., C. Shapiro and S. Z. Knezevic. 2001. Manure application effects on weed infestations. NC-Extension 189
  • Co-Author of four Annual Publications:
    • Guide for weed management in Nebraska.
    • Corn hybrids for Nebraska.
    • Soybean varieties for Nebraska.
    • Alfalfa varieties for Nebraska.
  • Weed Research for northeast Nebraska. Yearly report

Refereed Journal Articles

Critical Period of Weed Control

  • Lindquist, J.L., Evans, S.P., Shapiro, C.A., Knezevic, S.Z. 2010. Effect of nitrogen addition and weed interference on soil nitrogen and corn nitrogen nutrition. Weed Technology 24:50-58.
  • Gustafson T, S. Z. Knezevic, T. Hunt and J. L. Lindquist. 2006. Early-season insect defoliation influences the critical time for weed removal in soybean. Weed Sci. 54: 509-515.
  • Evans S. P., S. Z. Knezevic, C. Shapiro and J. L. Lindquist. 2003. Influence of nitrogen level and duration of weed interference on corn growth and development. Weed Sci. 51: 546-556.
  • Knezevic, S. Z., S. P. Evans and M. Mainz. 2003. Row spacing influences critical time of weed removal in soybean. Weed Technol. 17: 666-673.
  • Knezevic S. Z., S. P. Evans, E. Blankenship, R. VanAcker and J. L. Lindquist. 2002. Critical period of weed control: the concept and data analysis. Weed Sci. 50: 773-786.
  • Knezevic S. Z., A. Datta, J. Scott, R. Klein, and J. Golus. 2009. Problem weed control in glyphosate-resistant soybean (Glycine max L.) with glyphosate tank-mixes and soil-applied herbicide. Weed Technol. 23: 507-512.
  • Kappler B., S. Z. Knezevic et al. 2005. Comparison of glyphosate-based herbicides in Nebraska.Crop Manag. J. online:
  • Elmore R. W., Roeth, Nelson, Shapiro, Klein, S. Z. Knezevic and A. Martin. 2001. Glyphosate-resistant soybean cultivar yields compared to sister lines. Agron. J. 93: 408-412.

Dose Response Curves

  • Knezevic S. Z., A. Datta. J. Scott and L. D. Charvat. 2010. Application timing ad adjuvant type affected saflufenacil efficacy on selected broadleaf weeds. Crop Prot. 29: 94-99.
  • Knezevic S. Z., A. Datta, J. Scott and P. J. Porpiglia. 2009. Dose-response curves of KIH-485 for preemergence weed control in corn (Zea mays). Weed Technol. 23: 34-39.
  • Hock S, G. Wiecko and S. Z. Knezevic. 2008. Glyphosate dose affected control of field dodder (Cuscuta campestris) in the tropics. Weed Technol. 22: 151-155.
  • Hamill A., S. Z. Knezevic, K. Chandler, P. Sikkema, F. Tardif and C. J. Swancontrol in glufosinate tolerant corn (Zea mays L.). Weed Technol. 14: 578-585.ton
  • Leskovseck R. A.Datta. S. Knezevic and A. Simoncic. 2012. Common ragweed dry matter allocation and partitioning under different nitrogen density. Weed Biology and Management 12. 98-108.
  • Knezevic S. Z. et al.. 2004. Purple loosestrife control using herbicides: Single year application. Weed Technol. 18: 1255-1260.

Flame Weeding

  • Ulloa, S. M., Datta, A., Knezevic, S. Z. (2011). Growth stage influenced sorghum response to broadcast flaming: Effects on yield and its components. Agronomy Journal 103: 7-12.
  • Ulloa, S. M., Datta, A., Malidza, G., Leskovsek, R., Knezevic, S. Z. (2010). Yield and yield components of soybean [Glycine max (L.) Merr.] are influenced by the timing of broadcast flaming. Field Crops Research 119:348-354.
  • Ulloa, S. M., Datta, A., Knezevic, S. Z. (2010). Growth stage impacts tolerance of winter wheat (Triticum aestivum L.) to broadcast flaming. Crop Protection doi: 10.1016/j.cropro.2010.04.009.
  • Ulloa, S. M., Datta, A., Malidza, G., Leskovsek, R., Knezevic, S. Z. (2010). Timing of broadcast flaming influenced yield and yield components in sweet maize (Zea mays L. var. rugosa). Field Crops Research 118: 282-288.
  • Knezevic S. Z., J. F. Neto, S. M. Ulloa and A. Datta. 2009. Winter wheat (Triticum aestivum L.) tolerance to broadcast flaming. In Proceedings of the 8th EWRS workshop on Physical and Cultural Weed Control. Pages 104-109, Zaragoza, Spain.
  • Knezevic S. Z., C. M. da Costa, S. M. Ulloa and A. Datta. 2009. Response of corn (Zea mays L.) types to broadcast flaming. In Proceedings of the 8th EWRS workshop on Physical and Cultural Weed Control. Pages 92-98, Zaragoza, Spain.
  • Domingues A. C., S. M. Ulloa, A. Datta and S. Z. Knezevic. 2008. Weed response to broadcast flaming. RURALS.
  • Knezevic S. Z. and Ulloa S. M. 2007. Flaming: New potential tool for weed control in organically grown agronomic crops. J. Agric. Sci. 52: 95-104.


  • Baca F., S. Gosic-Dondo, A. Videnovic, B. Kresovic and S. Knezevic. 2008. Effects of planting date on the level of European borer infestation and corn yield. Maydica. 53: 111-115.
  • Lindquist J. L., D. C. Barker, S. Z. Knezevic and D. Walters. 2007. Comparative nitrogen uptake and distribution in corn and velvetleaf (Abutilon theophrasti). Weed Sci. 55:102-110.
  • Baca F., J. Levic, S. Stankovic, L. Stefanovic, M. Simic, S. Gosic-Dondo and S. Knezevic. 2007. Factors contributing to the population changes of major maize pests in Serbia. Maydica 52: 343-346.
  • Barker D. C., S. Z. Knezevic and J. L. Lindquist. 2006. Effect of nitrogen addition on the comparative productivity of corn and velvetleaf (Abutilon theophrasti). Weed Sci.54: 354-363.
  • Hock S., S. Z. Knezevic, C. Petersen, J. A. Easton and A. R. Martin. 2005. Germination techniques for common lambsquarters and Pennsylvania smartweed. Weed Technol. 20: 530-534.
  • Shrestha A., S. Z. Knezevic, R. C. Roy, B. Ball-Coelho and C. J. Swanton. 2002. Effect of tillage, cover crop and crop rotation on the composition of weed flora in a sandy soil.Weed Res. 42: 76-87.
  • Van Acker R. C. , A. G. Thomas, J. Y. Leeson, S. Z. Knezevic and B. L. Frick. 2001.Comparison of weed communities in Manitoba ecoregions and crops. Can. J. Plant Sci. 80: 963-972.
  • Knezevic S. Z., M. J. Horak and R. L. Vanderlip. 1999. Estimates of physiological determinants for red root pigweed. Weed Sci. 47: 291-296.
  • Swanton C. J., A. Shrestha, B. Ball-Coelho, R. C. Roy and S. Z. Knezevic. 1999. Effect of tillage systems, N, and cover crop on the composition of weed flora. Weed Sci. 47: 454-461.
  • Knezevic S. Z., P. H. Sikkema, F. Tardif, A. S. Hamill, K. Chandler and C. J. Swanton. 1998. Biologically effective dose and selectivity of RPA 201772 (isoxaflutole) for preemergence weed control in corn. Weed Technol. 12: 670-676.
  • Knezevic S. Z., S. F. Weise and C. J. Swanton. 1995. Comparison of empirical models depicting density of Amaranthus retroflexus L. and relative leaf area as predictors of yield loss in maize (Zea mays L.). Weed Res. 35: 207-214.

Book Chapters and Manuals

  • Knezevic, Datta, Bruening and Gogos, 2012. Propane Fueled Flame Weeding in corn, soybean and sunflower.
  • Taylor E., S. Z. Knezevic and S. M. Ulloa. 2008. Flaming for Weed Management. Chapter 4, pages 61-74. In: Integrated Weed Management: Fine Tuning the System. Extension Bulletin E-3065. (132 pages), Michigan State University, East Lansing.
  • Lindquist J. L. and S. Z. Knezevic. 2001. Quantifying crop yield response to weed population: Applications and Limitations in Biotic Stress and Yield Loss, edited by Robert K.D.Peterson and Leon Higley . CRC Press LLC, Boka Raton, Florida, 33431. ISBN 0-8493-1145-4.