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Systemic protection against Psa-V in spring

Kiwifruit
27.09.2018
Kiwifruit canopy at 25 mm leaf diameter, suitable for first ACTIGARD application
Kiwifruit canopy at 25 mm leaf diameter, suitable for first ACTIGARD application

Spring growth of kiwifruit is particularly susceptible to Psa-V infection.  Although copper is a useful contact protectant at this time, it does not move inside the plant to protect expanding leaves and shoots.

ACTIGARD® is highly systemic, moving upwards and outwards (in the xylem) and downwards (in the phloem), eliciting a response known as Systemic Acquired Resistance (SAR) which helps to protect the rapidly developing spring canopy against Psa-V infection.

Best use advice for spring applications of ACTIGARD

  • The first recommended spray timing of ACTIGARD (plus copper) in spring is when leaves are approximately 25 mm in diameter. This makes best use of its systemic movement of ACTIGARD to protect rapidly expanding growth.
  • The second key application timing for ACTIGARD (plus copper) is 1 to 7 days prior to flowering. This provides systemic protection over the flowering period when options for Psa-V control are limited, and infection risk remains high.
  • Apply 20 g of ACTIGARD per 100 litres of water as a dilute spray (200 g/ha).
  • As ACTIGARD can take up to 7 days to fully activate the plant, the addition of copper is recommended to give immediate protection, especially when applied prior to wet weather events.
  • To avoid the risk of residues, DO NOT spray female flowers or fruit with ACTIGARD.
  • If vines are under stress, delay the application of ACTIGARD until they have recovered and are actively growing.
  • ACTIGARD is compatible with: Kocide Opti®, Nordox®, Prodigy®, Movento®, Luna® Privilege, Timorex® Gold, and some foliar nutrient products.
  • Multiple product mixtures should always be tested for physical compatibility prior to use.
  • A maximum of four applications of ACTIGARD can be made in a season (harvest to harvest).

Crop safety of ACTIGARD in spring

  • A number of trials have been conducted to evaluate the crop safety of applying ACTIGARD in the spring, and whether it has any impact on canopy growth or fruit at harvest.
  • During spring 2015 Zespri contracted Plant & Food Research to spray ACTIGARD on unstressed Gold3 and Hayward vines in 4 orchards near Te Puke.  In these orchards ACTIGARD did not affect shoot elongation, crop load, fruit size, or the dry matter content of fruit (Ref: Does Actigard reduce orchard yield? New Zealand Kiwifruit Journal - September/October 2016). 
  • Syngenta also contracted 3 independent replicated trials (1 on Hayward and 2 on Gold3) in spring 2015, to evaluate if there was a relationship between ACTIGARD timing and the number of applications on canopy growth, yield and fruit quality. The results showed no negative impact on lateral length, leaf diameter, fruit weight or dry matter, either when ACTIGARD was applied alone or in mixture with copper.

Click here to download the latest Technote on how to best use Actigard for Psa-V control in spring.