Dimethoate suspended on many food crops

The Australian Pesticides and Veterinary Medicines Authority (APVMA) has suspended the use of dimethoate on a number of food crops due to potential dietary risks. New restrictions have been put into place that allow dimethoate to be used only on certain horticultural crops.

Wikipedia defines dimethoate as a widely used organophosphate insecticide used to kill insects on contact. It is old chemistry that was patented and introduced in the 1950s by American Cyanamid. Like other organophosphates, dimethoate is an anticholinesterase, which disables cholinesterase, an enzyme essential for central nervous system function. It is particularly effective against sucking insect pests such as aphids. It is also very useful for fruit fly control for many fruit and vegetable crops including capsicum, tomatoes and strawberries. The suspension of this insecticide is not expected to impact on greenhouse growers outside of Queensland where many vegetables and fruits going south of the border are treated with dimethoate.

The APVMA announcement follows the release of the 2011 Dimethoate Residues and Dietary Risk Assessment Report (August), which found that its use on many crops could exceed the recommended public health standard (the Acute Reference Dose).

“Some of the estimated exposures for consumers are above the Acute Reference Dose, reducing, but not breaching, the margins of safety that are normally in place to protect consumers,” said Dr Raj Bhula, Pesticides Program Manager.

“These safety margins, built into the APVMA’s risk assessment, provide a protective buffer to ensure that consumers will not actually be exposed to high levels of residues in food.

“If our risk assessment shows that these standards could be exceeded, the APVMA must remove or modify the use of the chemical on the crop so that consumption remains in line with the public health standard.”

The suspension will last for 12 months while the Authority completes further assessments on the chemical. It prohibits:

• use of dimethoate on certain horticultural crops
• use on all food producing plants in the home garden
• supply and possession of dimethoate products unless they carry the new instructions for use.

“Possession and use on some crops can continue provided the products carry the new instructions for use. Product registrants are requested to inform all parts of the supply chain that new instructions have been issued by the APVMA. All products in the supply chain and the marketplace must contain the new instructions prior to sale.”

The new use instructions and answers to frequently asked questions about the dimethoate suspension are available on the APVMA website (www.apvma.gov.au)