class: center, middle, inverse, title-slide # GR Volunteer Corn Control with mixture of Clethodim and Dicamba ### Vitor M. Anunciato ### 2020-11-19 --- class:center, hide-logo <div> <style type="text/css">.xaringan-extra-logo { width: 110px; height: 128px; z-index: 0; background-image: url(https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/patlablogo.png?raw=true); background-size: contain; background-repeat: no-repeat; position: absolute; right:1em;bottom:1em; } </style> <script>(function () { let tries = 0 function addLogo () { if (typeof slideshow === 'undefined') { tries += 1 if (tries < 10) { setTimeout(addLogo, 100) } } else { document.querySelectorAll('.remark-slide-content:not(.title-slide):not(.inverse):not(.hide_logo)') .forEach(function (slide) { const logo = document.createElement('a') logo.classList = 'xaringan-extra-logo' logo.href = 'https://pat.unl.edu/' slide.appendChild(logo) }) } } document.addEventListener('DOMContentLoaded', addLogo) })()</script> </div> **Interactions of Clethodim and Dicamba on Glyphosate-resistant Volunteer Corn Control** [Vitor Muller Anunciato](https://serialweedkiller.netlify.app/), Gabrielle de Castro Macedo, Daniel Araujo Doretto, Jeff A. Golus, Caio A. Carbonari, Greg R. Kruger <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/checkcontrol.png?raw=true" width=700 height= 350> <div align="left"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/ncwsslogo.jpg?raw=true" width=100 height= 100> --- ## Introduction + **Glyphosate Resistant Volunteer Corn** (GRVC) is a common weed in soybean fields [(Tao B. et al. 2007)](https://bioone.org/journals/Weed-Technology/volume-21/issue-1/WT-05-193.1/Efficacy-of-Glyphosate-Plus-Bentazon-or-Quizalofop-on-Glyphosate-Resistant/10.1614/WT-05-193.1.short). + Can reduce soybean yield through competition, cause problems with harvest, host insects and diseases, and contaminate soybean seeds at the harvest. [(Marquardt, P. T., & Johnson, W. G. 2013)](https://bioone.org/journals/weed-technology/volume-27/issue-4/WT-D-12-00188.1/Influence-of-Clethodim-Application-Timing-on-Control-of-Volunteer-Corn/10.1614/WT-D-12-00188.1.short). + **Clethodim** (WSSA Group 1) used in grass control in postemergence applications. However, **antagonistic interactions** have been reported when applied in **tank-mixtures with synthetic auxins** (WSSA Group 4). [(Blackshaw et al. 2006](https://www.cambridge.org/core/journals/weed-technology/article/broadleaf-herbicide-effects-on-clethodim-and-quizalofopp-efficacy-on-volunteer-wheat-triticum-aestivum/7BDD2D11DC2EA18A84774047D3A5AB8C); [Harre et al. 2020).](https://www.cambridge.org/core/journals/weed-technology/article/influence-of-24d-dicamba-and-glyphosate-on-clethodim-efficacy-of-volunteer-glyphosateresistant-corn/980D8BDC2427B5A22BF7597C8037B827) + Clethodim and dicamba mixture are utilized to **increase the spectrum of weeds control**. [(Underwood, M. G. et al. 2016).](https://www.jstor.org/stable/24856044?casa_token=3K7Vk94DHTgAAAAA%3AVvtWbfV7HNwjkvjG-p-h93_JriMsPbWCi4r2rMg6Fyvsnme37jlxG3w5vLnUmh8fvNKYvq3emknzcuUQmCHBV404awtG_T_xOik8F3CL78c7_wkTYXqf&seq=8#metadata_info_tab_contents) --- ## Objectives + To evaluate the effects of clethodim and dicamba tank-mixture on GRVC control at different heights, with and without the use of non-ionic surfactant (NIS). ## Hyphotesis + Non-ionic surfactant (NIS) will increase the control of GRVC when treated with the mixture of clethodim and dicamba. + As the plant height increase will decrease the control of GRVC when treated with the mixture of clethodim and dicamba. --- ## Study desing + Field planted at **Dryland Farm**, North Platte - NE, University of Nebraska-Lincoln/WCREEC, in **2019** and **2020**. + 62,500 seeds/ha (25,000 seeds/acre). + Plants heights: **30 cm** (12 in), **60 cm** (24 in) and **90 cm** (72 in). + Those fields study was conducted in **randomized complete block design** in a factorial treatment arrangement with 4 replications and 2 experimental runs. + Split in plots with 3 x 10 m (10 x 30 ft each). --- ### Materials and Methods + The treatments was applied with **backpack CO₂ sprayer** with 6 nozzles + **TTI 11002**. 140 L/ha (15 GPA), 276 KPa (40 psi), 1.74 m/s (3.9 mph). <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/mm.png?raw=true" width=600 height= 400> --- ### Treatments <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/trt.png?raw=true" width=800 height= 400> --- ## Statistical analysis + Biomass data were subjected to **ANOVA test** and means were separated using **Fisher’s LSD test** with **post-hoc Tukey test at α = 0.05**. + **Colby’s Equation** was used to determine the type of interaction occurred [Colby, S. R. (1967)](https://www.jstor.org/stable/4041058?seq=1#metadata_info_tab_contents). And the difference between the estimated and obseverd control values was compared by **studentized t test α = 0.1**. <div align="center"> ```math E = (X+Y) - (X*Y)/100 ``` <div align="left"> + **X** and **Y** are the effects of the **herbicides applied alone** (expressed as percent‐of‐control). + The **Observed control** for the herbicide mixture is then compared to the **E = expected control**. + <u>**If p value > 0.1**</u> + Obs **greater** Exp = SYNERGISM + Obs **less** Exp = ANTAGONISTIC + <u>**If p value ≥ 0.1**</u> + ADDITIVE --- ### First field trial no NIS - 2019 <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/fro.png?raw=true" width=1200 height= 500> --- ### Second field trial no NIS - 2020 <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/sro.png?raw=true" width=1200 height= 500> --- ### First field trial with NIS - 2019 <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/frw.png?raw=true" width=1200 height= 500> --- ### Second field trial with NIS - 2020 <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/srw.png?raw=true" width=1200 height= 500> --- ### Preceptation + Systemic herbicides as clethodim and dicamba are highly affected by the climate, the difference of precipitation between the field studies conduction could be derived from the difference of precipitation.[(Adkins, S. W. et al 1998](https://www.cabdirect.org/cabdirect/abstract/19982302488); [Zhou, J. et al 2007)](https://bioone.org/journals/weed-science/volume-55/issue-3/WS-06-173.1/Glyphosate-Efficacy-on-Velvetleaf-span-classgenus-speciesAbutilon-theophrasti-span-is/10.1614/WS-06-173.1.short) <div align="left"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/rain.png?raw=true" width=750 height= 450> --- ### Discussion + If the **control** of GRVC is realized **earlier** it has the best response hitting 80% in the lowest dose and **96% in the highest dose (136 g ai/ha)** when the **plants are sprayed with 30cm** of height. On the other hand, when the **plants had 90 cm the maximum control achieved was 58%**. Those results agree with [Costa et al 2014](https://www.scielo.br/scielo.php?pid=S0100-83582014000400002&script=sci_arttext) they highlighted the importance of completing the management in the transgenic volunteer corn plant development early stages. --- ### 30 cm <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/30cm.png?raw=true" width=1200 height= 400> --- ### 60 cm <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/60cm.png?raw=true" width=1200 height= 400> --- ### 90 cm <div align="center"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/90cm.png?raw=true" width=1200 height= 400> --- ### Example - plants 60 cm 28DAT. <div align="left"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/checkdicamba.png?raw=true" width=716 height= 500> --- ### Example - plants 60 cm 28DAT. <div align="left"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/clethodim76dicamba.png?raw=true" width=716 height= 500> --- ### Example - plants 60 cm 28DAT. <div align="left"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/clethodim102dicamba.png?raw=true" width=716 height= 500> --- ### Example - plants 60 cm 28DAT. <div align="left"> <img src="https://github.com/vitoranunciato/volunteercorncontrol/blob/main/docs/imagens/clethodim136dicamba.png?raw=true" width=716 height= 500> --- ## Conclusion + The mixture tends to be antagonistic independent of the presence or absence of the NIS. + The antagonistic effect is the predominant interaction, independent of the tested dose of clethodim it cants present a different interaction with dicamba. But even with the antagonic effect the mixture of 136 g ai/ha of clethodim with 560 g ae/ha of dicamba presents satisfactory control ±85% when the plants are treated at 30 cm + Results showed that cutting the rate of clethodim is not a good strategy for management of GRVC and timeliness is critical for the success of this tool in the field, because GRVC is not a conventional weed. --- ## Future studies Looking forward **if other adjuvants or other technologies** can overcome the antagonistic effect in the grasses control with clethodim in the **tank-mixture** with dicamba and therefore improve GRVC control on dicamba-tolerant soybean fields. --- ## Take-Away The best results for controlling GR volunteer corn are obtained in plants up to 30 cm high, and if a tank mix with dicamba is used, the highest dose of clethodim should be used to compensate for the antagonistic effect. <div align="right"> #Thank you --- ## References + Tao, B., Zhou, J., Messersmith, C. G., & Nalewaja, J. D. (2007). Efficacy of glyphosate plus bentazon or quizalofop on glyphosate-resistant canola or corn. Weed Technology, 21(1), 97-101. + Marquardt, P. T., & Johnson, W. G. (2013). Influence of clethodim application timing on control of volunteer corn in soybean. Weed Technology, 27(4), 645-648. + Blackshaw, R. E., Harker, K. N., Clayton, G. W., & O'Donovan, J. T. (2006). Broadleaf herbicide effects on clethodim and quizalofop-P efficacy on volunteer wheat (Triticum aestivum). Weed technology, 20(1), 221-226. + Underwood, M. G., Soltani, N., Hooker, D. C., Robinson, D. E., Vink, J. P., Swanton, C. J., & Sikkema, P. H. (2016). The addition of dicamba to POST applications of quizalofop-p-ethyl or clethodim antagonizes volunteer glyphosate-resistant corn control in dicamba-resistant soybean. Weed Technology, 639-647. + Harre, N. T., Young, J. M., & Young, B. G. (2020). Influence of 2, 4-D, dicamba, and glyphosate on clethodim efficacy of volunteer glyphosate-resistant corn. Weed Technology, 34(3), 394-401. --- ## References + Colby, S. R. (1967). Calculating synergistic and antagonistic responses of herbicide combinations. Weeds, 15(1), 20-22. + Adkins, S. W., Tanpipat, S., Swarbrick, J. T., & Boersma, M. (1998). Influence of environmental factors on glyphosate efficacy when applied to Avena fatua or Urochloa panicoides. Weed Research (Oxford), 38(2), 129-138. + Zhou, J., Tao, B., Messersmith, C. G., & Nalewaja, J. D. (2007). Glyphosate efficacy on velvetleaf (Abutilon theophrasti) is affected by stress. Weed science, 55(3), 240-244. + Costa, N. V., Zobiole, L. H. S., Scariot, C. A., Pereira, G. R., & Moratelli, G. (2014). Glyphosate tolerant volunteer corn control at two development stages. Planta Daninha, 32(4), 675-682.