Persistence behaviour and safety risk evaluation of pyridalyl in tomato and cabbage.

A field experiment was set up to evaluate persistence behaviour of pyridalyl in tomato, cabbage and cultivated field soil over two consecutive seasons. An analytical method was developed to analyze pyridalyl residues in different matrices and duly validated, based on single laboratory method validation criteria. Pyridalyl residues were detected and quantified using a gas chromatograph equipped with an electron capture detector. The compound exhibited low persistence in tomato, cabbage and soil. A safe waiting period of 17-18 d after final insecticide application needs to be maintained before harvesting the crop. Both dietary and soil ecological risk were assessed and it was found that the harvested vegetables were toxicologically safe for consumption. However, there was concern about insecticidal toxicity against the algal population of soil which needs to be reconfirmed by further studies.