Arable farmers phasing out potent pesticides

Foundation for Arable Research’s Richard Chynoweth says growers have already turned away from harmful insecticides being phased out even though it is limiting their options for controlling grass grubs. Photo / Foundation for Arable Research

Arable farmers have begun ruling out protecting crops with pesticides being banned in a phase-out by the Environmental Protection Authority (EPA).

The organophosphates of prothiofos, terbufos, fenamiphos and methamidophos are described by the authority as potent insecticides with “significant effects” on human health and the environment.

They are used to protect pasture and other crops such as carrots, potatoes, citrus, avocados, sweetcorn and cereals, and also for biosecurity purposes.

Arable growers most commonly apply terbufos and diazinon - also being removed - for countering grass grubs in pasture seed and other crops and methamidophos as a control for maize crops.

The EPA reassessed the chemicals in 2013, resulting in their approval for importing and manufacturing being revoked with a series of phase-out dates.

Prothiofos and terbufos pesticides were banned for use on August 1.

Methamidophos will be ruled out with an end date pushed out to July next year, while fenamiphos is only able to be used within this deadline by approved agencies for biosecurity work. Diazinon pesticides will be banned in 2028.

An EPA spokeswoman said the organophosphates’ health risks were well documented.

“They can cause damage to the nervous system, motor function, and to the development of children. With regard to the environment, these substances are harmful to birds, fish, and non-target insects.

“The EPA conducted a risk assessment for these substances, and it found that the risks to those using the substances and the environment could not be mitigated, even with the use of controls.”

Foundation for Arable Research herbage seeds project leader Richard Chynoweth said growers understood why the insecticides were being removed from the market and the need for them to be disposed of safely.

“Some of these are used in arable crops and some of them are used more in the horticulture and vegetable production areas. They should be disposing of them through the proper channels as a lot of these products are organophosphate insecticides which are not nice when handled the wrong way.”

He said terbufos was used by arable growers as grass grub product for pasture, cereals, brassicas, maize and sweetcorn, while methamidophos was used for corn and maize growing as well as potato growing.

“A lot of growers have gone away from them the past few years because they knew these removals were coming, but also because they realised they’re actually not that nice for people, especially the person applying them.”

Alternative insecticides for grass grub were diminishing with phorate removed in 2016, terbufos recently and diazinon in 2028.

A few biological and agrichemical products coming to market were showing promise, but growers were nervous as those being removed were the “go-to” for controlling grass grubs for a long time, he said.

“Growers have got a better understanding of life cycles and what they can do to reduce the impacts, but it’s still a big problem for a number of our growers trying to establish crops in the autumn and sometimes in the spring.”

The other insecticides being phased out were mainly for chewing insects and there were other chemical families on the market for them.

EPA’s spokeswoman said farmers needed to dispose of them with care as they were hazardous.

“People should not dispose of them in a landfill or through unregulated means,” she said.

“This could pose a risk to other people and to the environment through unsafe levels of exposure. [They] should contact a specialist hazardous chemical disposal company to make sure they are removed and disposed of safely.”

The four insecticides are banned in the European Union, while methamidophos, fenamiphos and prothiofos are not permitted in the United States and methamidophos is not approved in Australia.