Published on 28/07/2023
Armillaria (Armillaria novae-zelandiae) is a naturally occurring soil fungus that infects the roots of plants.
In kiwifruit vines, armillaria infection is a slow progressing disease that initially restricts production of the vine and eventually results in vine death.
The armillaria infection spreads into orchards from infected roots of other kiwifruit vines, dead tree stumps, and willow or pine hedges.
In healthy soils, the natural soil microbes suppress disease-causing fungi and bacteria. In soils with a balanced soil biology kiwifruit vines are able to withstand disease pressure from armillaria while in soils with unbalanced biology the disease-causing microbes are able to proliferate and infect plants.
BioStart has developed a two-phase biological programme for managing armillaria in orchard soils.
In phase 1 Terracin is applied to the soil in early August to control the armillaria.
Terracin contains Bacillus amyloliquefaciens Bs1b which works by disrupting the existing soil microbial population by producing antimicrobial compounds which suppress the growth of armillaria (and some other microbes).
This is followed by a second phase, where Mycorrcin is applied in early spring (budbreak)and early summer (flowering), which restores healthy biology in the soil.
Mycorrcin is used to restore the beneficial bacteria in the soil, to recreate the balance found in healthy soil after Terracin has done its reset.
Mycorrcin is a soil biostimulant that activates naturally occurring beneficial microbes present in your soil, including mycorrhizal fungi, which improve plant health, nutrient uptake, resilience, and root growth.
Trials in five armillaria infected kiwifruit orchards over three years showed that the BioStart Kiwifruit Programme reduced armillaria vine deaths by 88%.
Over the three-year trial 5.6 percent of the untreated vines had died whereas only 0.7% of the Terracin-treated vines had died.
In April, trial vines were assessed using a canopy disease scoring system that measured canopy health.
In the Terracin-treated vines at the end of year three the vine canopy disease scores had reduced by 32% but in the untreated vines they had increased by 34%.
This showed that the armillaria disease impact was worsening in the untreated vines, while the health of Terracin-treated vines was improving and being less affected by armillaria.
In a further trial yield was restored to previous levels after the vines recovered.
“The BioStart Armillaria Kiwifruit Programme is a great tool for rebalancing soil microbial populations and suppressing armillaria,” the company says.
For more detail visit biostart.co.nz.