Published on 21/01/2026
Words: BioStart
One such option is BioShield, a biopesticide initially developed in NZ by AgResearch and now further developed and manufactured by the NZ biological company BioStart.
For more than 30 years, BioStart has led the way in developing reliable biological solutions for NZ farmers and growers.
Built on an early understanding of the power of beneficial microbes, BioStart’s range now includes biological products that improve soil health, enhance plant performance, and support livestock productivity.
The company’s microbial fermentation technology underpins a suite of trusted products —from biostimulants that activate beneficial soil and plant microbes, to prebiotics that optimise gut health in livestock, and biocontrols that help growers manage diseases such as botrytis in grapes and sooty mould and sclerotinia in kiwifruit.
BioShield Grass Grub offers targeted control of this potentially costly insect pest.
The active ingredient in BioShield Grass Grub is a naturally occurring bacterium, Serratia entomophila, which causes amber disease in grass grub larvae.
Once introduced in autumn, when grass grubs are most susceptible to amber disease, the infected larvae spread the disease through the population, leading to a natural and ongoing reduction in grass grub numbers.
Because Serratia entomophila affects only NZ grass grub larvae, BioShield offers a targeted, safe and environmentally responsible solution.
It poses no risk to livestock, birds, beneficial insects or other soil life, with proven results.
BioShield is used successfully in pasture restoration, newly planted vineyards, and annual cropping systems.
In pasture trials using BioShield Grass Grub Granules, results showed that within just three months, amber disease was well established and grass grub numbers had dropped by 85 per cent, with further declines continuing through the year.
That means farmers can expect a strong initial knockdown and ongoing population suppression after application.
BioShield Grass Grub is ACVM-registered, certified organic, and manufactured in NZ, ensuring full traceability and consistent quality.
It is available in both granule and liquid formulations, offering flexibility for different farming systems and application methods — whether sprayed or broadcast.
BioStart is focused on innovation for the future, and continues to invest in research and development, including work on a second-generation grass grub biopesticide designed to extend application windows and improve control in both pasture and arable systems.
For agribusinesses and farmers looking to replace synthetic insecticides with a proven, biological control, BioShield Grass Grub offers an effective, environmentally friendly option.