Biosecurity prevention better than cure for invasive weeds

Some weeds are getting hard to kill on farms throughout the country. Photo / 123RF

The Foundation for Arable Research (Far) is reminding arable farmers to get on board with biosecurity - and says it is their livelihood at stake.

Far/Ministry of Primary Industries (MPI) sustainable farming fund project lead Abie Horrocks said on-farm plans needed to be in place to protect farms at their borders.

Ms Horrocks, who was speaking at a Women in Arable meeting in Ashburton last week, said arable farmers needed to be prepared if herbicide resistance was found.

The foundation recognised that herbicide resistance was an increased threat for the New Zealand arable industry. Some weeds were becoming harder to kill, particularly wild oats and Italian ryegrass in Canterbury.

Ms Horrocks said biosecurity had crossover with health and safety requirements.

However, the preventive approach could save a lot of time and money.

''The cost to the business [if incursion occurred] could be huge.''

Ms Horrocks said Far would appreciate any feedback on biosecurity from those in the industry.

Known incursions included velvet leaf, pea weevil, black grass and red clover casebearer moth.

But other pests known about included the brown marmorated stink bug and the Russian wheat aphid. Both could cause economic damage as they attacked a variety of New Zealand crops.

While not established in New Zealand, they had been caught at the border, on passengers and in imported goods.

Eradication of pea weevil and black grass was still possible, although at considerable cost, Ms Horrocks said.

However, velvetleaf was one of the worst weed pests internationally because of how much it could reduce yields as it competed for nutrients, space and water.

The spread nationwide of the red clover casebearer moth indicated it had been in the country for some time.

''It's probably been here too long,'' she said.

It significantly reduced crop yields and in the first year was hard to detect but increased significantly the second year.

Keeping a biosecurity plan active worked and helped with early detection.

The plan should include machinery movements on and off the farm, and logs should be kept to know the locations of contractors.

Allowing only clean machinery on site should be factored in.

''Early detection is key,'' Ms Horrocks said.

Herbicide-resistant weeds were also an increased threat for the arable industry and there was not enough discussion about them.

Communication between neighbours was important because the weeds were a real threat to the industry.

''It's a threat that is obviously there ... and if you get [herbicide-resistant weed] on the farm, it will be there forever,'' she said.

-By Toni Williams

Central Rural Life