Quirky Psa risk graphs

02 February 2023

Those receiving KVH daily Psa reports direct to their inbox or by logging into the KVH website, may be surprised by lower Psa risk forecast from some stations over coming days despite ongoing rain.

For example, the Katikati weather station currently predicts nil risk through to Sunday 5 February even though rain is expected. This is not a mistake but rather relates to the influence of warmer day and night temperatures.

The rate of Psa development is negligible once temperatures reach over 20°C, so higher day and night temperatures lessen risk. When day or night-time temperatures fall again, risk returns.

Growers can use the Psa risk model to help plan girdling timings, with a reminder of the importance of good tool hygiene and the recommendation to apply summer rate copper to girdles in parts of the orchard where Psa risk is higher.

Read more about all the tools within the KVH Weather & Disease Portal, and how to get daily reports automatically delivered to your inbox here.

Image: Katikati weather station predictive data.