New Research Supports Post-Harvest Use Of ACTIGARD

Kiwifruit crop canopy

A collaborative research project was started in 2019 between Syngenta, Zespri/KVH and Plant & Food Research to get a better understanding of ACTIGARD® use post-harvest and what impact it had on Gold3 and Hayward vines when applied at this time.

Tony Reglinski, Senior Research Scientist at Plant & Food Research says, “The best way to understand the effect of ACTIGARD® in the post-harvest window is to look for changes in the defence gene expression in the ACTIGARD® treated vines compared with the untreated vines, where an increase in gene expression is likely to equate to an increase in protection against Psa.”

Studies completed over two seasons# confirmed that a post-harvest application of ACTIGARD® induced the upregulation of specific market genes that are associated with plant defence in both Gold3 and hayward vines.  This highlighted the value of using ACTIGARD® post-harvest to protect vines against Psa infection.

They showed that leaf quality at time of application influenced gene expression.  As leaves began to senesce and show signs of yellowing the response to ACTIGARD® declined.

These results support the use of well-timed (ie at least 50% of the canopy leaves still green) ACTIGARD® applications post-harvest, to help protect Gold3 and Hayward vines against Psa infection.

Apply ACTIGARD® at 200 g/Ha with copper immediately post-harvest as a foliar spray.  A second application can be made 21-days later provided the canopy is still mostly green.  

Take care to prevent spray drift onto unharvested fruit in adjacent blocks to avoid the risk of residues on fruit.

For more information click here to download the latest post-harvest Kiwifruit Technote for ACTIGARD®.