U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Application Technology Research: Wooster, OH
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                                    Software
                People

                    Staff Listing
                                    Careers


        


                    Departments
                        Agricultural Engineering
                                    Entomology
                                    Horticulture
                                    Plant Pathology
                                    IR-4 programSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Midwest Area Wooster, Ohio Application Technology Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            XU, LINYU - The Ohio State Universityitem
                                            Zhu, Hepingitem
                                            OZKAN, ERDAL - The Ohio State Universityitem
                                            BAGLEY, BILL - Wilbur-Ellis Companyitem
                                            Derksen, Richarditem
                                            Krause, Charles
  Submitted to: Transactions of the ASABE
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 3/1/2010
                                    Publication  Date: 5/29/2010
                                    Citation: Xu, L., Zhu, H., Ozkan, E., Bagley, B., Derksen, R.C., Krause, C.R. 2010. Adjuvant Effects on Evaporation Rates and Wetted Area of Droplets on Waxy Leaves. Transactions of the ASABE. 53(1): 13-20.Interpretive Summary: Pesticide efficacy is often correlated with its spread area (wetted area) and evaporation time on a leaf surface, and it may be reduced if the active ingredients in droplets do not uniformly spread out and remain on a leaf surface especially for the surface of difficult-to-wet plants. Also, chemical residues may form large crystals that cannot remain on foliages after droplets dry. This research investigated the effect of different classes of spray additives on droplet evaporation, spread and residual pattern after droplets deposited on various types of waxy leaf. The investigation quatitatively demonstrated that droplet evaporation, spread area and residual pattern formation varied greatly with spray additive type and leaf waxy level. In general, selection of the appropriate class of adjuvants significantly improved deposit formation on waxy leaves, leading to more effectiveness of pesticides. Therefore, to maximize efficacy and minimize chemical use, pesticide dosage, chemical formulations and application methods should be recommended differently for different crops under specific environmental conditions.
                                Technical Abstract: The use of an appropriate adjuvant for pesticide applications is a critical process to improve spray deposit characteristics on waxy leaves and to reduce off-target losses. After deposition and evaporation, residue patterns of 500 μm sessile droplets that incorporated four classes of adjuvants on five different waxy plants were investigated. Droplets were generated with a single-droplet generator and deposited on target leaves placed in an environmentally-controlled chamber at 60% relative humidity and 25oC. Adjuvants tested were two types of oil-based Crop Oil Concentrate (COC) and Modified Vegetable Oil (MSO), a Nonionic Surfactant (NIS), and a type of mixture Oil Surfactant Blend (OSB). Water-only droplets were also tested for comparative purposes. The five waxy plants were difficult-to-wet and had a water contact angle greater than 90o. The water-only droplets did not spread at all and formed extremely small wetted areas on the leaf surface. The addition of an adjuvant to the spray solution significantly reduced the contact angle and increased the wetted area, but the change/improvements varied with the plant specie and the adjuvant class. In general, the MSO and NIS enhanced the droplet spread and maintained the droplet evaporation rate on the waxy leaf surfaces. After evaporation, the residues formed patterns of “coffee rings”.  Droplets with oil-based adjuvants had more uniform residual distribution in the deposition patterns than droplets with the surfactant adjuvant. Results of this study demonstrated that selection of the appropriate class of adjuvants significantly improved deposit formation on waxy leaves, leading to more effectiveness of pesticides.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov