ABSTRACT
BACKGROUND: The 2018 Farm Bill defines hemp as Cannabis sativa L. with a tetrahydrocannabinol (THC) concentration not more than 0.3% on a dry weight basis where THC is implied to be total THC (THCTotal) including both acid (Δ9-THCA) and neutral (Δ9-THC) forms. OBJECTIVE: Effect of temperature and mass were studied to determine the quickest time to prepare fresh hemp suitable for grinding without affecting THCTotal. Proficiency testing program data were also analyzed to compare THCTotal contents on a dry versus wet weight basis. METHODS: Fresh hemp of 150 and 400 g were freeze-dried or heat-treated at 50 °C, 60 °C, and 70 °C for various lengths of time up to 72 hours. Ground hemp was analyzed for moisture content via AOAC 934.01 and THCTotal via liquid chromatography/mass spectrometer (LC/MS) or gas chromatography with flame ionization detection (GC/FID). A data set analyzed from a proficiency testing program included moisture and THCTotal from 20 to 67 laboratories on 12 analytical samples circulated from 2020 through 2022. RESULTS: The quickest drying time of 24 h occurred at 70 °C with 150 g. These conditions did not affect THCTotal content on a dry weight basis. Twelve proficiency testing program analytical samples ranged from 5.8 to 11.4% moisture and 0.144 to 0.399% THCTotal on a wet weight basis. An increase in reported THCTotal on a dry weight basis compared to a wet weight basis ranged from 0.002 to 0.027% with a significant difference occurring in only one analytical sample. CONCLUSIONS: Suitable condition for drying hemp without altering THCTotal content was 24 h at 70 °C. Determining residual moisture in oven-dried ground hemp to calculate THCTotal content on a dry weight basis provides no benefit given minimal difference between contents on dry versus wet weight bases, interlaboratory variability, and terpene volatilization.
ABSTRACT
Device structure, light source height, and climatic factors can potentially affect the catching of target pests in light traps. In this study, the installation of an anti-escape cover in a newly designed light trap significantly increased the number of catches of tea leafhoppers, Empoasca onukii, an economically significant pest of tea gardens, and it prevented 97.95% of leafhoppers from escaping. A series of assessments were performed in the field and showed that the optimal trapping window of the light trap was between 1.5 and 2.5 h (2 ± 0.35 h) after sunset, and the starting time of the window was positively correlated with the sunset time. The number of leafhopper catches decreased sharply when the height of the light source was above the flight height range of E. onukii adults. The height of the light source was optimal between 20 and 40 cm above the tea canopy. The efficacy of the light traps for capturing leafhoppers decreased in the autumn peak period. High numbers of leafhopper catches by the newly designed light trap in the summer could reduce E. onukii population sizes in the autumn. Overall, the newly designed light trap can be used to reduce E. onukii adult populations in tea gardens.