Ultra High Performance Liquid Chromatography – Pesticide Residue analysis

Ultra High Performance Liquid Chromatography - Pesticide Residue analysis

Report Date: 07/19/2015
Project: 616   Year: 2014
Category: ACP Vector
Author: Michael Rogers
Sponsor: Citrus Research and Development Foundation

Report for period ending 9/30/14 During the period of 9/30/14 to 12/31/14 we continued work analyzing leaf tissues in order to more accurately quantify the levels of neonicotinoids present in leaf tissues. Leaf samples from more than 500 trees of different size classes treated with different rates of neonics were ground in liquid nitrogen and any potential pesticide residues within extracted, the extracts then held in the freezer for later analysis. Extracts were then analyzed using LC/MS/MS to quantify the levels of parent compounds and their metabolites in the leaf extracts. While analyses of all samples have not yet been completed, preliminary results show a consistent trend in the quantity of neonic present and tree size/rate of product applied. This work will be continued. Field trials were also continued to build upon work in previous years examining whether soil-applied neonicotinoid applications will move into the citrus flowers during bloom (in particular nectar) and pose any risk to pollinators. These studies are being conducted at the request of the EPA in order to maintain the expanded labeling of soil-applied neonics for use in citrus. Should any potential risks be identified, this project also will identify alternative timing of applications that could be recommended to mitigate any risk that might be identified. This field work began in April of 2014 with neonic applications being applied to assigned blocks of trees every 6 weeks. The purpose was to determine if the neonic applications would accumlate in the plant over time causing excessive risk to pollinators through expression in nectar. Because our previous work suggested that neonics are likely to move into nectar at differing rates, we examined seven different schedules (treatment rotations) of neonics applied every 6 weeks. The final plots were treated in October of 2014. During the next reporting cycle, the plots will be in bloom and we will collect nectar for analysis of potential neonic residues.

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