Psa protectants

12 October 2022

The recent frost has provided another challenge for many, in what has already been a tough year. With many orchards facing significant frost damage, and the potential for further cold weather, it is important to remain vigilant to the threat of Psa.

Psa protection should take priority especially where there have been gaps in protection ahead of frost events, but also on sites with previous history of Psa impacts.

Late October to early November is typically when symptoms show an upswing and we know Psa infection typically occurs 14 days before symptoms are visible, making these next two weeks important protection periods in our calendar.

Psa protection choice is important. As there is time pressure to get products on effectively, updated information from the Zespri Crop Protection Standard (CPS) on products for frost damage has been distributed and is available on the Zespri Canopy here and is copied below:

Growers have a number of products available – including Aureo Gold, Actigard, Kasumin, Copper, and Botry-Zen, (dependant on vine stress).

If looking to use a bactericide, we would like to encourage Kasumin rather than the alternative Key Strepto. We understand flowering is fast approaching, the Zespri Crop Protection Programme states application of Kasumin should not be within 21 days of flowering. This was to include a buffer for grower mis-step or unexpected timing of flowering.

To support grower response to the recent frosts, Zespri will reduce the 21-day window of Kasumin application to 14 days hopefully giving growers enough time to apply if this is their product of choice. This is still more conservative than the label which states application up to one week prior to flowers opening to allow for any possible residue buffer.

Summer rate copper remains the proven backbone of Psa protectant programmes with applications ahead of wet weather, providing robust ongoing protection to damaged tissue. For copper applications ensure recommended rates are maintained and ensure product is applied in good drying conditions.

KVH has several types of resources available to assist growers with Psa advice, including:

  • Our Psa Best Practice Guide provides year-round guidance for protecting and managing your orchard in a Psa environment. It includes advice based on scientific research and on-orchard experience.
  • There is also a seasonal wall chart poster available that details cultural methods and spray planning as part of building a Psa plan that matches your orchard. We have A3 sized copies printed that can be mailed to you – please provide a postal address to the office.
  • A series of online Psa resources have been created to support growers, managers and post-harvest gain a greater understanding of Psa management activities on-orchard and share practical knowledge with their teams. Including both video and print, these resources are easy-to-follow and thought provoking when used to develop Psa disease management programmes.
  • A Spotlight on Psa, produced alongside Zespri. This is available online and graphically provides an understanding of the Psa disease cycle and maximising your Psa programme's potential.
  • The KVH Weather & Disease Portal is an online, weather-based decision support tool to assist growers with orchard management in a Psa environment. Weather station data and weather forecast information is combined to provide customised access to unique weather information, disease information and interpretations. Log in here to access the portal or view our handy 'how to login' guide.

KVH recommends you work with your pack-house to decide strategies to manage Psa-V on your orchard, or contact us directly with any specific questions. Technical support from Farmlands, and PGG Wrightsons - Fruitfed teams can also provide excellent advice on Psa product choice and strategies to rebuild damaged canopies.

NZKGI’s most recent Special Update (from earlier this week) details pastoral care options and we encourage you to take these resources and sources of assistance into consideration if you are facing increased pressure:

  • The Rural Support Trust offers someone to talk to about your pressures, including financial pressure, and they can put you in contact with experts who can provide you with advice here.
  • Farmstrong has great resources on what you can do to deal with challenges to look after yourself and the people in your business here.
  • GoodYarn is a free workshop to give you the practical tools and confidence to be able to talk to people in rural communities about mental health and will be held at Waimana (12.10), Otamarakau (14.10), Edgecumbe (17.10) and Opotiki (02.11). For more information, email the Rural Support Trust here.