The dissipation of fipronil, chlorpyrifos, fosthiazate and ethoprophos in soils from potato monoculture areas: first evidence for the enhanced biodegradation of fosthiazate.
BACKGROUND
A limited number of pesticides are available for the control of soil pests in potato. This, together with the monoculture nature of potato cultivation, does not favour chemical rotation, increasing the risk of reduced biological efficacy due to microbial adaptation. The dissipation of three major organophosphates (chlorpyrifos, ethoprophos and fosthiazate) was studied in comparison with fipronil, an insecticide recently introduced in potato cultivation, in 17 soils from potato monoculture areas in Greece to explore the extent of enhanced biodegradation development.


RESULTS
The dissipation time of the four pesticides varied in the different soils, with DT50 values of 1.7-30.8 days, 2.7-56 days, 7.0-31.0 days and 24.5-116.5 days for fosthiazate, chlorpyrifos, ethoprophos and fipronil, respectively. A rapid dissipation of ethoprophos and fosthiazate in two soils with previous exposure to these nematicides provided first evidence for the development of enhanced biodegradation. Sterilisation of the given soils inhibited the dissipation of fosthiazate. Additionally, fosthiazate dissipation in the soils increased upon repeated applications.


CONCLUSIONS
The development of enhanced biodegradation of fosthiazate in soils from potato monoculture regions was verified. This is the first report of enhanced biodegradation for this chemical. Further studies will focus on the isolation of microorganisms responsible for the dissipation of fosthiazate.
Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
Evangelia S
ES
Papadopoulou
Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
Stathis
S
Lagos
Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
Flora
F
Spentza
Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
Evangelos
E
Vidiadakis
Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
Panagiotis A
PA
Karas
BASF Hellas, Athens, Greece.
Tassos
T
Klitsinaris
Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece.
Dimitrios G
DG
Karpouzas
D000969:Antinematodal Agents / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004390:Chlorpyrifos / Q000378:metabolism; D006115:Greece; D007306:Insecticides / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000378:metabolism; D063086:Organothiophosphates; D009946:Organothiophosphorus Compounds / Q000378:metabolism; D011720:Pyrazoles / Q000378:metabolism; D012988:Soil Microbiology; D011198:Solanum tuberosum; D053778:Thiazolidines / Q000378:metabolism
D000969:Antinematodal Agents; D007306:Insecticides; D009943:Organophosphorus Compounds; D063086:Organothiophosphates; D009946:Organothiophosphorus Compounds; D011720:Pyrazoles; D053778:Thiazolidines; C001182:ethoprop; C493102:fosthiazate; D004390:Chlorpyrifos; C082360:fipronil
chlorpyrifos; dissipation; enhanced biodegradation; ethoprophos; fipronil; fosthiazate; potato cultivation