Location: Sugarcane Research Unit
Title: Pyraclostrobin wash-off from sugarcane leaves and aerobic dissipation in agricultural soil Authors
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 17, 2014
Publication Date: February 17, 2014
Citation: Fulcher, J.M., Wayment, D.G., White Jr, P.M., Webber III, C.L. 2014. Pyraclostrobin wash-off from sugarcane leaves and aerobic dissipation in agricultural soil. Journal of Agricultural and Food Chemistry. 62(10):2141-2146. DOI: 10.1021/jf405506p Interpretive Summary: The fungal sugarcane pathogen brown rust (Puccinia melanocephala) reduces sugarcane yield. The EPA authorized the use of Headline® fungicide to control the disease. The active ingredient is pyraclostrobin. There is little information related to the wash-off potential or soil residual of the chemical. A lab study was conducted to determine the length of time the chemical could be expected to stay in soil. The data indicate that 50% and 90% of the pyraclostrobin was degraded in 60 and 282 d, respectively. Wash-off studies on sugarcane indicate that the fungicide does not wash off the sugarcane leaves after 48 h. If applied according to label recommendations (not within 48 h of rainfall) the fungicide is expected to have minimal environmental impacts and assist in the control of brown rust. However, if rain washes the material off and onto the soil, it can persist for a moderately long time, compared to other pesticides used in sugarcane production.
Technical Abstract: In order to mitigate damage from the fungal sugarcane pathogen brown rust (Puccinia melanocephala), a Section 18 Emergency Use Label was put in place by the EPA for the application of pyraclostrobin (trade name Headline® SC; produced by BASF) on sugarcane in 2008. In order to assess the dynamics of this fungicide in Louisiana soil, samples (n=24) from an non-treated field were spiked with pyraclostrobin (3.1 ug/g) and analyzed in laboratory conditions over the course of 63 days using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) dSPE / HPLC-UV. Modeling was done using Microsoft Excel to predict dissipation times (DT). Pyraclostrobin was found to follow biphasic kinetics with DT50 and DT90 values of 60 and 282 days, suggesting it is moderately persistent to persistent in soils. Wash-off studies on sugarcane indicate that the fungicide is resistant to wash-off after 48 h. If applied according to label recommendations the fungicide is effective against brown rust with minimal environmental impacts.