Environmental fate of metalaxyl and chlorothalonil applied to a bentgrass putting green under southern California climatic conditions

Abstract

Putting greens usually receive high inputs of fertilizers and pesticides to meet the high demand for visual quality and to overcome the stress from close mowing and traffic. In this study, two commonly used fungicides, metalaxyl (methyl N-(methoxyacetyl)-N-(2,6-xylyl)-DL-alaninate) and chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile), were evaluated for their partitioning and persistence in a bentgrass (Agrostis palustris Huds) putting green under southern California climatic conditions. The putting green site was constructed according to the US Golf Association (USGA) specifications. Lysimeter assemblies installed at the center of each plot were used to monitor the leachate, flux chambers were used to measure volatilization, clippings were collected to determine the residues on grass, and soil cores were sampled to determine residues in the soil profile. Results showed that cumulative volatilization loss accounted for 0.10 and 0.02%, clipping removal 0.11 and 0.13%, and cumulative leaching 0.71 and 0.002% of the applied metalaxyl and chlorothalonil, respectively. The two fungicides were mainly found in the top 10 cm of the soil profile due to the high organic carbon content in the thatch and mat layers. The dissipation half-life was 1.4 days for metalaxyl and 4.9 days for chlorothalonil on grass, shorter than those found in agricultural fields. This study showed that, under normal turf management practices, the offsite transport of the parent fungicides was minimal. Future research should focus on investigating the fate and mobility of the metabolites of the fungicides.

Turfgrass Dissipation of Cyazofamid

“…The residues collected in the clippings, after suitable mathematical conversions were applied to adjust for the different surface areas collected (clipping residue x area for 5 cores/5 square feet = corrected clipping residue), were surprisingly low, with 2.2% of the applied material removed from North Carolina and only 0.7% removed at Virginia. Losses due to clipping compare well with literature values on other compounds (6,7,8) where liquid formulations were <1% and granular formulations were 1.2-8%. The formulation used (Ranman® 400SC) is a suspension concentrate which may behave more like a granular than a liquid.…”

Fungicide Leaching from Golf Greens: Effects of Root Zone Composition and Surfactant Use

“…This risk may be further aggravated by finger flow resulting from soil water repellency (Bauters et al, 1998), which is a common phenomenon in golf greens. Indeed, fungicides have often been detected in drainage water from golf greens and surface water influenced by runoff from golf courses (Petrovic et al, 1998; Cohen et al, 1999; Wu et al, 2002; Ludvigsen et al, 2004; Strömqvist and Jarvis, 2005).…”

Pesticidas no perfil de solos em áreas de plantação de cebolas em Ituporanga, SC

“…Por outro lado, os fungicidas foram cerca de 50% mais detectados na profundidade de 0 a 20 cm que nas outras duas profundidades apresentando, portanto, maior adsorção na região de superfície devido, provavelmente, ao tempo de aplicação (possuem registro para serem utilizados em cultivo de cebola) e se sabe que os fungicidas são mais persitentes no solo que os herbicidas. Alguns pesquisadores também encontraram dois fungicidas: o metalaxil e o clorotalonil, em maior quantidade na camada de aproximadamente 10 cm atribuindo-se, a isto, o alto teor de carbono orgânico e o revolvimento do solo da superfície (Wu et al, 2002). Através da frequência de detecção nota-se que os pesticidas alcançam a profundidade de 80 a 100 cm, podendo representar potencial de contaminação das águas subterrâneas.…”