Water Quality

Thiobencarb Monitoring Season Set to Start

water monitoring

Monitoring for 2020

Thiobencarb monitoring starts at all five sampling sites tomorrow, April 28. We base the monitoring on planting and timing of thiobencarb applications with several counties receiving notices of intent to apply Abolish. 

Monitoring typically takes place on Tuesdays and Thursdays except this year with the addition of Wednesday during certain weeks. We are on an assessment monitoring schedule with the Rice WDR, which expands sample collection beyond a Tuesday/Thursday program. The total thiobencarb monitoring will remain a ten-week schedule and include the same number of samples as previous years.

Changes to the REI and field posting

The thiobencarb restricted entry interval (REI) was decreased from 7-days to 12-hours. The change is reflected in a supplemental label, which must be present and available (in-hand) at time of application. Without the supplemental label, you are held to the 7-day REI and field posting requirements. You can receive the supplemental label from your Valent representative, thiobencarb suppliers or a link to the CRC pesticide update provided last week. 

For more information, contact the CRC’s Industry Affairs Manager Roberta Firoved at rfiroved@calrice.org or (916) 206-5039.

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Thiobencarb Management Calendar

The information in this twelve-month chart is just a snapshot of the management necessary to maintain thiobencarb. At the CRC, we work to provide information on the management practices, stewardship updates and the monitoring results because product maintenance does not end with the last application, cumulation of all water-holds or the collection of the final water sample. Every person using, applying and recommending thiobencarb takes ownership in successful management of the herbicide. Management requires constant diligence and coordination with the growers, registrants, pilots, applicators, pest control advisers, county agricultural commissioners and state regulators to assure continual usage of this important herbicide. 

water monitoring

Thiobencarb Update with Exceedance Report

Monitoring results were at the performance goal of 1.5 µg/L on May 12 and May 28. The detections were noted at the Colusa Basin Drain 5 and Butte Slough 1 sites. On June 2, the duplicate sample for quality control had an exceedance of 1.8 µg/L while the standard lab result was at 1.2 µg/L. The samples were from the Colusa Basin Drain 1 site outside Knight’s Landing. All sampling results recovered to non-detection levels on June 4.