Residues and Uptake of Soil-Applied Dinotefuran by Lettuce ( Lactuca sativa L.) and Celery ( Apium graveolens L.)

Pesticides have been used for decades to protect agricultural products and increase productivity by controlling crop pests. However, the frequent application of pesticides on crops or soil leads to the accumulation of their residues in the environment, which will be subsequently absorbed by plants and finally translocated to edible parts. This study aimed to investigate the uptake of soil-applied dinotefuran and three major metabolites by lettuce and celery from the previous season’s applications and analyze their residues in soil and consumable parts. Dinotefuran was soil-applied at plant back intervals of 30 and 60 days (PBI-30 and PBI-60). Residues of dinotefuran and its metabolites in 50% and 100% mature lettuce leaves and celery shoots, soil after application, at planting, and at 50% and 100% plant maturity were estimated. Half-lives and bio-concentration factors were calculated. The uptake of dinotefuran by lettuce and celery ranged between 23.8% and 28% and between 51.73% and 53.06%, respectively. Respective half-lives (days) of dinotefuran applied on PBI-30 and PBI-60 were 1.33–1.54 and 0.91–2.16 in lettuce soil and 0.9–1.47 and 0.79–1.65 in celery soil. Residues were below Korean MRLs in PBI-60 and most PBI-30 samples. The calculated risk assessment parameters indicated that negligible risk could be expected. The current study recommends growing the next crop 60 days after harvesting the first crop, but not less than 30 days.