Progress 10/01/08 to 09/30/13
Outputs
OUTPUTS: Dislodgeable foliar residues (DFR) can be a primary route of human exposure following pesticide application to turfgrass areas. In this study, DFR were determined over a 15-day-period following application of the broadleaf weed herbicide carfentrazone to a Tall Fescue lawn. Dislodgeable foliar residues were determined by wiping treated turfgrass with a distilled-water-dampened cheesecloth and analyzing samples using GC/MS. Less than 20% of the total applied carfentrazone was dislodged with 13.8% of DFR occurring immediately after application. Dislodgeable residue as determined 1, 4, and 8 hours after treatment (HAT) contributed an additional 5.5% to the total applied carfentrazone dislodged from the foliar surface. One day after treatment (DAT), dislodgeable residue levels had declined to below 1% of the total applied carfentrazone. By day 3, carfentrazone DFR were nondetectable. This work indicates that carfentrazone poses minimal risk to human health via dermal exposure when applied at the labeled rate. Persistence of dislodgeable foliar residues (DFR) and soil residues following pesticide application are an important concern because of their implications for human exposure. This study evaluated the effect of application volume, post-application irrigation and mowing height on the persistence and distribution of foliar and soil residues of the pre-emergent herbicide herbicide prodiamine over an 11-day period following application to a tall fescue lawn. Increasing application volume from 810 to 1,236 L / ha reduced DFR by an average of 3.8% over the entire study with significantly lower residue levels 3 hours after treatment (HAT), and 5, 7, and 11 days after treatment (DAT). Increased application volume resulted in an average of 46% less prodiamine soil residues with significantly lower residue levels 1, 3, and 11 DAT. Clippings removed from plots treated with an application volume of 810 and 1,236 L / ha resulted in approximately 13% reduction in the amount of applied prodiamine lost from the treated surface. Post-application irrigation reduced DFR by an average of 10% for the entire study with significantly lower residue levels at all sampling periods except 3 DAT. Post-application irrigation reduced soil residue levels 1 DAT but then increased residue levels 3, 7, and 11 DAT by an average of 37% when compared to plots that did not receive post-application irrigation. Soil residues were not significantly different during any sampling period throughout the experiment. Clippings removed from plots that received post-application irrigation exhibited a 12% reduction in the amount of applied prodiamine lost from the treated plots. Increased mowing height did not significantly affect DFR throughout the entire study. Increased mowing height resulted in an average of 28% higher prodiamine levels in soil for all sampling periods except 3 DAT; however, they were not statistically different during any sampling period. Prodiamine residue levels resulted in a maximum estimated hazard quotient of 1.18 x 10-3 for study, indicating no potential human toxicological effects from maximum field residue levels. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Approximately 20% of the total applied carfentrazone was dislodged with 13.8% DFR loss occurring 0 HAT after application. One day after application, dislodgeable residue levels had declined to below 1% of the total applied carfentrazone. Carfentrazone residue levels resulted in estimated hazard quotients < 1 for the entire study, indicating no human toxicological implications. Increasing application volume from 810 to 1236 L ha-1 reduced prodiamine DFR by an average of 3.8% for the entire study with significantly lower residue levels 3 HAT, and 5, 7, and 11 DAT. Increased application volume resulted in an average of 46% less prodiamine soil residues with significantly lower residue levels 1, 3, and 11 DAT. Clippings removed from plots 3 DAT resulted in a < 1% reduction in the amount of applied prodiamine lost from the treated surface. Post-application irrigation reduced prodiamine DFR by an average of 10% for the entire study with significantly lower residue levels at all sampling periods except 3 DAT. Post-application irrigation resulted in increased soil residue levels 3, 7, and 11 DAT by an average of 37%. Increased mowing height did not result in significantly different prodiamine DFR or soil residues through out the entire study. Approximately 35% of the total applied bifenthrin was dislodged over 15 days with 34% DFR loss occurring immediately after application. Maximum bifenthrin DFR immediately after application resulted in an estimated HQ >1 indicating possible human toxicological implications. Eight HAT < 1% of applied bifenthrin can be dislodged from the leaf surface resulting in estimated HQ values < 1, indicating no possible human toxicological implications.
Publications
- John, C.V., R.J. Cooper and Damian Shea. 2006. Dissipation of foliar carfentrazone residues following application to turfgrass. Agronomy Abstracts. 26. (Published on CD Rom).
|
Progress 10/01/06 to 09/30/07
Outputs
During the reporting period field research continued to evaluate the persistence of dislodgeable foliar residues (DFR) following application of the preemergence herbicide prodiamine to tall fescue (Festuca arundinacea Schreb.) lawn-type turf. The effect of application volume, post-application irrigation and mowing height on the persistence and distribution of foliar and soil residues were determined following application of prodiamine at a rate of 793 g of a.i. per ha. Foliar and soil residues were determined over an 11-day period following 10 April 2006 application. Application variables included: an application volume of either 810 or 1,236 L per ha; no post-application irrigation or irrigation with 0.6 cm immediately following application; application to tall fescue maintained at a mowing height of either 7.6 or 12.7 cm. DFR samples were obtained from plots receiving all combinations of treatment variables. Samples were obtained from a 220 x 20 cm subplots and were
taken three and eight hours after treatment (HAT) and at noon 2,3,5,7, and 11 days after treatment (DAT). Soil samples were collected 1,3, 7, and 11 DAT from each treatment combination from plots to a depth of 7.6 cm using a 2.5 cm diameter soil probe.
Impacts
Increasing application volume from 810 to 1,236 L per ha reduced DFR by an average of 3.8% over the entire study with significantly lower residue levels 3 HAT and 5, 7, and 11 DAT. Increased application volume resulted in an average of 46% less prodiamine soil residues with significantly lower residues 1, 3, and 11 DAT. Post-application irrigation reduced DFR by an average of 10% over the entire study with significantly lower residue levels at all sampling periods except 3 DAT. Post-application irrigation reduced soil residue levels 1 DAT but then increased residue levels 3, 7, and 11 DAT by an average of 37% when compared to plots that did not receive post-application irrigation. Soil residues were not significantly different during any sampling period throughout the experiment. Clippings removed from plots that received post-application irrigation exhibited a 12% reduction in the amount of prodiamine lost from treated plots. Increased mowing height did not affect DFR
during the study. Prodiamine residue levels on foliage resulted in a maximum estimated hazard quotient of 0.00118 for the study, indicating no potential human toxicological effects from maximum field residue levels.
Publications
- John, C.V., R.J. Cooper and Damian Shea. 2006. Dissipation of foliar carfentrazone residues following herbicide application to turfgrass. Agronomy Abstracts. 26. (Published on CD Rom).
|
Progress 10/01/05 to 09/30/06
Outputs
Work continued during 2007 in an effort to determine if supplemental applications of seaweed-based biostimulants could improve the summer stress tolerance of putting green creeping bentgrass (Agrostis stolonifera) in central North Carolina. Treatments were applied on approximately 14 day intervals to creeping bentgrass mown at about 0.125 inches. Visual quality was evaluated every two weeks during the season by rating individual plots using a scale of 1 - 9 where 1 = brown, low quality turf, 5 = acceptable quality, and 9 = dark green, dense, high quality turfgrass.
Impacts
Research will continue during 2004 to evaluate additional materials under field conditions for their potential to improved the quality and growth of various turfgrasses. If materials are identified which do improved turfgrass performance, this might allow improved quality and environmental stress tolerance with the effect of reducing costs associated with reseeding or sodding damaged turfgrass areas.
Publications
- No publications reported this period
|
Progress 10/01/04 to 09/30/05
Outputs
During 2005, the focus of this project shifted from evaluating humic substances to determining the level of dislodgeable foliar residues (DFR) following application of commonly used pesticides to tall fescue lawn-type turf. The purpose of this research was to evaluate the influence of application spray volume, mowing height, and clipping removal on the level of DFR and herbicide efficacy in a tall fescue home lawn situation. The herbicide Speed Zone (2,4-D; mcpp; dicamba + carfentrazone) was applied to a mature tall fescue (Festuca arundinacea Schreb.) area maintained as lawn turf at the Lake Wheeler Road Turfgrass Research Center, Raleigh, NC using a Chemlawn type gun similar to that used in the lawn care industry. The application was maade at 2 gallons of solution / 1,000 ft2 to tall fescue mown at a 3" mowing height. Triplicate samples of foliar residues were obtained from the treated area within one minute of application and again 1, 4 and 8 h after application on
the day of application (Day 1. Samples were also obtained at 1200 h on Days 2, 3, 5, 7, 11, and 15. following Barricade7 application. Dislodgeable foliar residues were collected using a 9 x 23-cm piece of cheesecloth moistened with deionized water. A 30 x 30 cm area of pesticide-treated turfgrass was wiped left to right and then right to left so that the entire area was wiped twice. Inital residue analysis has shown that the level of DRF decline dramatically following application. It appears that once the spray solution has dried on the foliage, potential dislodgement by persons using the area is probably negligible. Work will continue to evaluate other commonly used pesticides, focusing on insecticides and herbicides.
Impacts
This research is of interest because of the increasing number of home lawns being treated with lawn care pesticides. It is important to quantify the amount of dislodgeable foliar residues remaining on treated areas following application in order to estimate potential residue exposure.
Publications
- Bruneau, A.H., C.H. Peacock, R.J. Cooper and E.J. Erickson. 2004. Management programs for the upper transition zone in the southeastern United States. Proc 1st Intl. Conf. of Turfgrass Mgmt. and Sci. for Sports Fields. Acta Horticulturae. No. 661:551-559.
- Peacock, C.H., D.J. Lee, W.C. Reynolds, J.P. Gregg, R.J. Cooper, and A.H. Bruneau. 2004. Effects of salinity on six bermudagrass cultivars. Proc 1st Intl. Conf. of Turfgrass Mgmt. and Sci. for Sports Fields. Acta Horticulturae. No. 661:193-198.
|
Progress 10/01/03 to 09/30/04
Outputs
Creeping bentgrass (Agrostis stolinefera L.) is commonly used as a putting green grass in the uppper South and transition zone. Although it performs well for much of the year, its lack of heat tolerance often results in unacceptable quality and/or death during the hot summer months. In an effort to improve summer persistence and quality, golf course superintendents often apply biostimulant materials to putting greens during the summer months. Biostimulants are products which when applied in small amounts, may improve plant rooting, photosynthesis, or growth by supplying some non nutritive stimulative compound. This research was conducted on an established L-93 creeping bentgrass putting green located at the Lake Wheeler Field Research Laboratory in Raleigh, NC. The rootzone mix at the site was constructed according to USGA guidelines. Treatments were initially applied on 07 May 2004 to 3 ft. x 10 ft. plots arranged in a completely randomized block design utilizing
four replications. Treatments were applied on a 14 day schedule from 07 May through 29 September using a CO2-powered backpack sprayer equipped with a single 8003E even flat fan nozzle calibrated to deliver 1.0 gallon of solution / 1,000 ft2. The turf was maintained at a mowing height of 0.125 inches throughout the study. Pesticides were applied only as need on a curative basis to control disease and insect pests. Irrigation was applied as needed to prevent drought stress. PanaSea Plus, containing sea-weed extractand other materials, applied at 3.0 oz / 1,000 ft2 in combination with various wetting agents had no significant effect on turfgrass quality throughout the season. Clipping yield was also determined for treated plots during the season and revealed that treatments did not significantly affect plant vigor. This was the second consecutive season of evaluation using the products and the potential for these particular treatments to improve the quality of creeping bentgrass seems
limited.
Impacts
Research will continue during 2005 to evaluate additional materials under field conditions for their potential to improved the quality and growth of various turfgrasses. If materials are identified which do improved turfgrass performance, this might allow improved quality and environmental stress tolerance with the effect of reducing costs associated with reseeding or sodding damaged turfgrass areas.
Publications
- No publications reported this period
|
Progress 10/01/02 to 09/30/03
Outputs
Growing creeping bentgrass (Agrostis stolonifera L.) in the souteastern United States during the summer months is a difficult task. Since creeping bentgrass is a cool-season grass, its performance often declines notably during the summer months due to high temperatures and humidity. In an effort to improve summer performance, many golf course superintendents make supplemental applications of products containing biostimulants to their putting greens. Applications of seaweed-based products (PanaSea Plus or CPR) were applied to a creeping bentgrass putting green in Raleigh, NC on a 14 day schedule beginning on 16 May 2003 and continuing through 20 October 2003. PanaSea Plus applied at either 2.0 or 3.0 oz. of material per 1,000 sq.ft. had no effect on turfgrass quality compared to non-treated turf. Plant growth rate and root mass were also unaffected by the treatments. Similarly, applications of the product CPR at rates or 6.0 or 9.0 oz. per 1,000 sq.ft. had no effect on
turfgrass quality, rooting, or growth rate of creeping bentgrass.
Impacts
Research will continue during 2004 to evaluate additional materials under field conditions for their potential to improved the quality and growth of various turfgrasses. If materials are identified which do improved turfgrass performance, this might allow improved quality and environmental stress tolerance with the effect of reducing costs associated with reseeding or sodding damaged turfgrass areas.
Publications
- No publications reported this period
|
|