OLCA Research

Control of Crabgrass and Environmental Fate of Preemergence Herbicides Applied as a Single Versus a Split Application.

Principal Investigator(s):
                                        Dr. David Gardner                                Dr. John Street
                                        Address: 202 Kottman Hall                   202 Kottman Hall
                                        2021 Coffey Rd                                    2021 Coffey Rd
                                        The Ohio State University                     The Ohio State University
                                        Columbus, OH 43210                           Columbus, OH 43210
                                        Telephone: (614) 292-9002                 Telephone: (614) 292-9091
                                        FAX: (614) 292-3505                            Fax: (614) 292-3505
                                        E-Mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it               E-Mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

Project Description: In order for a preemergence herbicide to effectively control crabgrass (Digitaris sp.), it must persist above a certain minimum concentration for up to 16 weeks. Previous research has suggested that sequential applications of the same pesticide may enhance microbial degradation of the active ingredient, thus decreasing the persistence of the product in the turf profile. Despite this, it is commonly recommended to apply sequential applications of preemergence herbicides in order to lengthen the time of effective control of crabgrass. Our goal is to optimize the control of crabgrass in a medium maintenance turfgrass lawn. To do this we will conduct a study to measure both the control of crabgrass and the chemical dissipation of three commonly used preemergence herbicides: pendimethalin, prodiamine, and dithiopyr applied either as a single application or using two sequential applications 6 weeks apart. The objectives of this project are (1) to determine the control of crabgrass afforded by three common herbicides applied either as a single application or sequentially, (2) to measure the residues of the pesticides remaining in the soil following application and (3) to correlate crabgrass control to pesticide residue levels.

How Ours is Different: Previous crabgrass control studies that examined single versus split applications did not measure the pesticide residues in the soil after application. This research will measure pesticide residues at regular intervals during the study using a Hewlett Packard HP 5890 Gas Chromatograph fitted with a thermionic detector in order to correlate the control of crabgrass to the actual level of preemergence herbicide remaining in the soil.

Potential Benefits: Development of a model that would predict the effect of application schedule on dissipation of a pesticide and its corresponding potential to provide long term control. This would allow us to develop recommendations for the optimal method of applying the pesticide to maximize the chance of achieving season long crabgrass control with a preemergence herbicide.

Deliverables: Data on the control of crabgrass following application of three popular herbicides applied either as a single or sequential application. Data on the dissipation of these herbicides that will be used to make recommendations as to whether single or sequential applications will result in most optimal control of crabgrass.