Estimation of Diafenthiuron Residues in Cardamom (Elettaria cardamomum (L.) Maton) Using Normal Phase HPLC: Dissipation Pattern and Safe Waiting Period in Green and Cured Cardamom Capsules

Diafenthiuron is an effective insecticide used for pest management in cardamom. Residues of diafenthiuron and its degradation/dissipation pattern in cardamom were determined to work out safe waiting period. Samples were collected after three sprays of diafenthiuron @ 400 and 800 g a.i ha−1 and the residues extracted in acetonitrile and quantified in normal phase HPLC in UV detector. Diafenthiuron was detected in 6.61±0.1 min. The limits of detection (LOD) and limits of quantification (LOQ) were determined to be 0.01 and 0.05 μgmL−1. The initial deposits were found to be 3.82 and 4.10 μg g−1 after sprays of diafenthiuron @ 400 g a.i ha−1 in the first and second experiments, respectively. Nearly cent percent of residues dissipated at 10 days after treatment in the recommended dose of diafenthiuron 400 g a.i ha−1 and the half life varied from 2.0 to 2.8 days with a waiting period of 5.5 to 6.7 days in green capsules of cardamom. The waiting period was 5.4 to 7.0 days in cured capsules of cardamom. With harvest being the focal point for enforcement of residue tolerances, the suggested waiting period of seven days is safe without the problem of pesticide residues in harvestable produce

Selective toxicity of diafenthiuron to non-target organisms: honey bees, coccinellids, chelonus, earthworms, silkworms and fish

Diafenthiuron, an insecticide widely used in the management of pests of cardamom and cotton, was assessed for its toxicity-effect on beneficials commonly found in these ecosystems. Diafenthiuron was found to be toxic to honey bees, the prime pollinators of crop plants. Diafenthiuron at the highest tested dose caused 40% mortality to the coccinelid grubs at 48 h after treatment so, diafenthiuron was found to be slightly harmful. Monocrotophos, on the other hand has been found to be a highly toxic pesticide. Diafenthiuron is moderately harmful to the adults of Chelonus blackburni L. The testing was done using the insecticide diafenthiuron. An insecticidecoated vial (scintillation) bioassay was performed. It was found that there was 86.67% mortality in 48 h, at the recommended dose. Diafenthiuron is highly toxic to the silkworm, killing more than 80% of the caterpillars in 24 h, at all the doses tested. Diafenthiuron, even in the highest dose tested, is non-toxic to the earthworm, Perionyx excavatus, which was found to have a 3.33% mortality. As far as fish are concerned, the common carp, Cyprinus carpio L., is found to be highly susceptible to diafenthiuron and even doses 10 times lower than the field dose can kill the fish within 6 h