Sorption of the nematicide fluensulfone in six UK arable soils – implications for control of the potato cyst nematode Globodera pallida

Abstract

Batch adsorption experiments were performed to determine the sorption of the nematicide fluensulfone as a technical-grade and a granular formulation (as Nimitz 15G) in six UK arable soils. The Freundlich and equilibrium sorption coefficients and , respectively, were generally low. and correlated positively with soil organic matter in all instances. The sorption kinetics was similar for both forms, but the was about four times lower for Nimitz 15G than the technical-grade, suggesting concentration dependency of fluensulfone sorption. The low sorption of fluensulfone across the soils indicates that partitioning of fluensulfone to the soil liquid phase may be unlimited. Therefore, substantial availability in the soil to be effective is likely. Sorption, therefore, may not limit fluensulfone efficacy. Nonetheless, these results call for cautious use of the nematicide because leaching is possible.

From Old-Generation to Next-Generation Nematicides

“…The fate of fluensulfone in soil has not been studied much. Log P of the compound is 1.96 [12], which suggests that it is much less leachable than oxamyl, but leaching is still possible [65]. Its DT 50 is 7-17 days, depending on the soil type and environmental conditions, such as the soil temperature and water contents [12].…”

“…Organic matter is another factor affecting the mobility of the compound in the soil; peat moss mixed into the sandy soil also reduces the vertical movement of compounds [84]. The reduction in distance moved in the soil is mainly due to adsorption to organic matter and clay [65,85]. [86,87].…”

Fluensulfone sorption and mobility as affected by soil type

“…This has been previously noted by Norshie et al . (). Although sorption was variable across the soils tested, K D values were low, indicating that fluensulfone has a low sorption capacity.…”

“…Sorption of non‐fumigant nematicides is highly correlated with various soil properties (Pantelelis et al, ; Qin et al, ; Simon et al ., ; Bilkert and Roa, ; Gerstl, ). The soil sorption potential of fluensulfone and the effects of soil properties on its mobility have been reported (APVMA, ; Norshie et al ), but further analytical soil testing will assist in examining its behavior. Using a bioassay, Oka et al .…”

“…There is some information about fluensulfone adsorption and mobility from bioassay type research, and Norshie et al . () noted that adsorption to OM does occur, suggesting that fluensulfone may be mobile through soils with low amounts of clay or OM.…”