Weed Science Research/Instruction Post-Tenure Review William K. Vencill Department of Crop & Soil Sciences University of Georgia Athens, GA

Background Appointment (55% Research, 45% Instruction) Research Areas Herbicide Resistance Herbicide Physiology Herbicide Soil Interactions Weed Management Systems in Herbicide-Tolerant Crops

Research – Herbicide Resistance

S.O. Duke: WSSA – Feb., 2011, Portland, OR

Total Acres Exposed to Herbicide Sites of Action for Corn, Soybean, Cotton NASS, 2007

From Gerwick, Sept., 2010, Agrow S.O. Duke; WSSA – Feb., 2011, Portland, OR

Counties with Glyphosate-Resistant Amaranth

Glyphosate Resistance Target site resistance Vacuolar sequestration Overexpression EPSP target site Does this occur in all glyphosate-resistant Palmer amaranth populations? Do multiple mechanisms occur in some populations?

EPSPS Activity in Palmer F2 Plants 54 copies, 22 µM 39 copies, 13 µM 7.5 copies, 42 µM 1 copy, 67 µM PNAS, 2010

Other resistance research Triazine-Resistant Palmer Dinitroaniline-Resistant Palmer Multiple-Resistant Palmer ACCase-Resistant Large Crabgrass and Ryegrass

Triazine Resistant Palmer Amaranth 0 100 1000 5000 10000 Atrazine (g/ha)

Atrazine Metabolism

Weeds with Resistance to More than one Mechanism of Action The number of weed species with resistance to more than one herbicide mechanism of action has increased drastically since 1990. Currently, 50 weed species with multiple forms of resistance have been confirmed. Source: www.weedscience.org, Ian Heap, March 2011

R – Non-target R – ALS Trp 574 -> Asp R – ALS Ser 653 -> Asp R – ALS Ala 122 -> Trp Susceptible

ALS-Resistant Palmer Amaranth

ALS Resistance What are the mechanisms of the non-target site resistance?

Questions about Herbicide Resistance Why are some weeds more prone to developing resistance than others? Why have some weeds never developed resistance even with intensive pressure? Why are some herbicide MOA more prone to resistance development than others?

Proposed Resistance Risk Classification High – ALS, ACC, PS II-T 3 6 9 1 (High) Single Herbicide MOA 1.5 3.0 4.5 0.5 (Mod. – Low) MOA Rotation Only 0.75 2.25 0.25 (Low) Integrated Pest Mgmta Med – EPSP, Auxin, DNA, PS I, PDS 2 4 1 0.5 Integrated Pest Mgmt Low – VLCFA, GS 0.25 0.125 ELEIN, Senecio, SOLXX, Salsola, Poa, DIGXX Avena, ECHCG, XANST, SORHA, SETXX, AMAXX, AMBXX, LOLXX, KOCXX, CHEAL, Conyza Blue – Highest Risk Orange – Higher Risk Yellow – Moderate Risk Green – Low Risk a Integrated Pest Mgmt refers to use of all weed control tools available such as crop rotation, tillage, preventative practices, etc.

Herbicide-Resistant Weeds Loss of Options Herbicide MOAs Trade Name Est. Loss of Efficacy ALS (in soybeans) Pursuit, Staple 95 % ALS (in cotton) Staple 60 % ACCase Assure, Fusilade 30 % Glycine Roundup and others Photosystem II Cotoran, Diuron 5 % PPO Valor, Reflex 3 % Auxin Analogs 2,4-D, Clarity (dicamba) 1 % Glufosinate Liberty (Ignite) < 1 % slide 2) critical mechanisms of action and loss of utility ALS (Staple) %loss 67% ACCase (Select) %40 Glycine (RoundUp) %35 Glufosinate (Ignite) %1 PPO (Valor, Reflex) %5 PS2 (Cotoran, Diuron) %10 Phenoxy (2,4-D) %1 ALS in Soybeans %100

Other projects New herbicide for other crops Pearl millet Sunflower Sweet sorghum Canola Stevia

APHIS – WSSA Publications . APHIS contracted with WSSA to have a state of the art paper written on herbicide-resistance Second project contracted with APHIS to write a paper on recommendations Both papers served as foundation for National Academy of Sciences Summit on Strategies to Manage Herbicide-Resistant Weeds

Weed Science Editor Editor since 2009 ~200 manuscripts/year Reduced time from submission to first response from 62 d to 45 d

Teaching

Teaching Weed Science – CRSS 4340/6340 Weed Science Lab – CRSS 4340L/6340L Herbicide Physiology – CRSS 8330-8330L Team teach Pesticide Use – CRSS(ENTO)(PATH)4250 Integrated Pest Mgmt – ENTO(CRSS) 4740/6740 Chemical Toxicology – PHRM 8930 First Year Odyssey Seminar

Instruction-Related Accomplishments Undergraduate Coordinator (since 1997) College Curriculum (since 2000) Chair – 2007 and 2011 University Curriculum (2000-2007) General Education (2002-present) Board of Regents Committee to reform Core Curriculum (2008) Board of Regents Council of General Education (since 2010) ConnectUGA Project Advisory Team (2012-2015)

Awards & Honors 2011 D.W. Brooks Faculty Award for Excellence in Teaching 2012 – Senior Teaching Fellow

Teaching – Graduate Students In the past five years, have mentored six graduate students on a thesis program; four on a non-thesis program. Serve as the Crop & Soil Science representative on the Master of Plant Protection Pest Management Program On all student’s committees Proctor an exit written exam on weed science

Administrative Duties

http://www.uga.edu/effectiveness/sp.html

Other Administrative Duties Supervised Office of Faculty Affairs Promotion and tenure committees Workshops for faculty University Program Review University System Ethics Policy Committee Budget Review SACS Leadership & Compliance

Any Questions?