Researchers found new biopesticide for porina control

AgResearch scientists are working on a chemical-free biopesticide that can kill one of New Zealand's worst pasture pests - the porina caterpillar.

The caterpillar and with another pest, the grass grub, cost farmers an estimated $100 million a year in destroyed pasture and control measures.

The biopesticide is based on a naturally-occurring bacterium, Yersinia entomophaga, discovered during a search for alternatives to health-threatening chemical pesticides which are being phased out.

When eaten by pests, the bacterium releases toxins that cause rapid death but does not harm earthworms or bees.

AgResearch biocontrol and biosecurity scientist Colin Ferguson says it knows the biopesticide will work, but now have to come up with the most effective formula for applying it.

He says it is considering spray or bait as delivery mechanisms.

Mr Ferguson says the company hasn't closed the door on either method and is one or two years' away from bringing the product to market.

Mr Ferguson says this particular biopesticide won't be suitable for grass grub control, but it could be used on a range of other pests, including the apple orchard pest, bronze beetle, diamond back moths, cabbage white butterfly and locusts.

AgResearch is developing porina control product with the fertiliser company Ballance Agri-nutrients.