Improving Pesticide Efficacy Through the Use of Wetting Agents Dr. Charles H. Peacock NC State University
Topics to be covered How Localized Dry Spots related to hydrophobic soil conditions develop Effectiveness of Wetting Agents USGA/GCSAA research efforts New materials Use of wetting agents in pest management programs
Understanding Localized Dry Spot (LDS) Defined: a dry area of sod and soil that resists water as normally applied; Caused by various factors such as heavy thatch, soil or fungal organisms; Often effectively treated with use of a wetting agent.
Understanding LDS Types of wetting agents: Anionic negatively charged, more phytotoxic, easily leached, short residual, wet quickly Cationic positively charged, held tightly in soil, less phytotoxic, wet slowly Nonionic neutral in charge, persistent, least phytotoxic Past these were ethers, esters, alcohols
Understanding LDS Why LDS develops: Water is a very polar molecule = O H H + +
Understanding LDS H = O H + + = O H = O H + + H H + +
Understanding LDS Cohesion water to water attraction through hydrogen bonding Surface tension created by polarity of water molecules Nonionic wetting agents have polar and nonpolar areas Polar = hydrophilic Nonpolar = hydrophobic
Understanding LDS Sand or Soil With Organic Coating
Understanding LDS Organic coating = O Sand or Soil With Organic Coating Polar ends H + Nonpolar ends H +
Effectiveness of Wetting Agents Most wetting agents are glycopolymers modified alkylated polyol nonionic polyols alkoxylated polyols glucoethers propoxylated polyethylene glycols
Effectiveness of Wetting Agents Most wetting agents are glycopolymers CH 3 HO-(CH 2 CH 2 O) x -(CH 2 CHO) y -(CH 2 CH 2 O) x -H
Effectiveness of Wetting Agents Polar ends = O Sand With Organic Coating H + Nonpolar ends H +
Effectiveness of Wetting Agents
Effectiveness of Wetting Agents
Effectiveness of Wetting Agents
USGA/GCSAA Wetting Agent Research Project Nine locations: NY, MI, MO, WA, CA, NM, TX FL, GA Ten wetting agents and a control Four month duration in 2003 & 2004 Data collected: Turf Quality - visual Turf Color - visual Phytotoxicity - visual Degree of soil hydrophobicity = WDPT
USGA/GCSAA Wetting Agent Research Project WDPT
USGA/GCSAA Wetting Agent Research Project Water Droplet Penetration Test Time (seconds) Degree of Hydrophobicity 0-5 none 5-60 slight 60-600 moderate to high 600-3,600 severe Above 3,600 extreme
USGA/GCSAA Wetting Agent Research Project Products Tested Aqueduct Brilliance Cascade Plus Hydro-Wet LescoFlo Naiad Primer Select Respond 2 Surfside 37 TriCure Study Cost = $200,000
Results Switch to pdf file Florida
Switch to pdf file Results Texas
Texas Results Switch to pdf file
Results California Switch to pdf file
Results Georgia Switch to pdf file
Results Georgia Switch to pdf file
Results Georgia Switch to pdf file
Results Missouri Switch to pdf file
Results New York Switch to pdf file
Results Dr. Larry Stowell PACE Turfgrass Research Institute in California www.paceturf.org
Ability of wetting agents to reduce soil hydrophobicity. Number of times in top performing group. Product Reduced soil hydrophobicity Aqueduct 12 Brilliance 13 Cascade Plus 12 Hydro Wet 10 LescoFlo 9 Naiad 0 Primer Select 11 Respond 2 2 Surfside 37 2 TriCure 11 Total number of trials 14
Effect of wetting agents on turf. Number of times use decreased turf quality. Product Decreased turf quality Aqueduct 2 Brilliance 1 Cascade Plus 1 Hydro Wet 1 LescoFlo 0 Naiad 0 Primer Select 2 Respond 2 0 Surfside 37 0 TriCure 2 Total number of trials 9
Results The products that most consistently reduced hydrophobicity (soil water repellency) were Aqueduct, Brilliance, Cascade Plus, HydroWet, Primer Select and TriCure. Products that consistently did the best job of reducing hydrophobicity also unfortunately had potential (though limited potential) to cause some reduction in turf quality. However, this decrease in quality was seen in a maximum of two out of nine locations. And in most cases, it is likely that the benefits of reduced water repellency will outweigh the potential for turf damage.
Results Products that consistently performed poorly in reducing hydrophobicity included Naiad, Respond 2 and Surfside 37. As luck would have it, these products were among the group that had the least potential for reducing turf quality as well. Ah well.
New Products New Chemistry!! Revolution - Aquatrols PBS 150 Aqua Aid
New Products Switch to Revolution PowerPoint Presentation
New Products PBS 150 Aqua Aid
Understanding LDS
Understanding LDS
Understanding LDS
New Products New Chemistry!! Revolution - Aquatrols PBS 150 Aqua Aid Both introduced since 2005, not included in the trial!!
Pesticide Efficacy Interactions Water repellency and soil structure significantly impact the way water moves into the soil. Soil-directed pesticides applied on the surface depend on the movement of water to get them into the soil profile. Water repellent soils can channel water and the chemicals it carries unevenly through the root zone.
Pesticide Efficacy Interactions This can result in uneven coverage. Examples where this is more critical would include: preemergence herbicides soil active insecticides root active fungicides
Pesticide Efficacy Interactions Randy Kane and Lee Miller Chicago District Golf Association 1999-2002 The wetting agent Aqua-Gro L inhibited annual bluegrass seeding to a limited extent in our tests. They could not offer an explanation of the mechanism of action.
Pesticide Efficacy Interactions Randy Kane and Lee Miller Chicago District Golf Association This formulation of Aqua-Gro is no longer manufactured.
Take Home Message Good information is available on a number of wetting agents. Newest products which have new chemistry were not included in the tests.