Dissipation kinetics and consumer risk assessment of novaluron + lambda-cyhalothrin co-formulation in cabbage

Area of Science:

• Agricultural Chemistry
• Environmental Science
• Food Safety

Background:

• Cabbage is susceptible to various insect pests and diseases, necessitating effective control measures.
• Novaluron (chitin synthesis inhibitor) and lambda-cyhalothrin (synthetic pyrethroid) are used against cabbage pests.
• The dissipation kinetics and risk assessment of their combination formulation in cabbage were previously uninvestigated.

Purpose of the Study:

• To evaluate the safety of a novel combination formulation of novaluron and lambda-cyhalothrin on cabbage.
• To determine the dissipation kinetics and residue levels of the insecticides in cabbage crops.
• To conduct a comprehensive dietary risk assessment for consumers of treated cabbage.

Main Methods:

• Multi-location field trials were conducted across different agro-climatic regions in India.
• Cabbage crops were treated with the combination formulation at recommended and double recommended doses.
• Residues were extracted using a modified QuEChERS method and analyzed via Gas Chromatography-Electron Capture Detector (GC-ECD) and Gas Chromatography-Mass Spectrometry (GC-MS).

Main Results:

• The half-life (t_1/2) of novaluron ranged from 1.77-3.38 days, and lambda-cyhalothrin ranged from 1.36-3.82 days, depending on the dose.
• Calculated Maximum Residue Limits (MRLs) for novaluron and lambda-cyhalothrin at a 3-day Pre-Harvest Interval (PHI) were 0.6 and 1.5 mg kg^-1, respectively.
• Risk assessment parameters including Hazard Quotient (HQ), Theoretical Maximum Daily Intake (TMDI), and hazard indices (% aHI, % cHI) were below acceptable levels.

Conclusions:

• The combination formulation of novaluron and lambda-cyhalothrin demonstrated safe dissipation kinetics in cabbage.
• Dietary risk assessments indicated no significant health risks to consumers from consuming treated cabbage.
• The findings provide valuable data for establishing MRLs and conducting risk assessments for similar pesticide combinations on food crops.