Important time for Psa protection
Cold snaps and windy wet weather have added to vine stress in the past month and for some Hayward growers the first signs of Psa leafspot and sepal infection are evident. These symptoms indicate infection has occurred in the previous 14 days, and application of Psa products is now important to avoid reinfection which can lead to further leafspot and flower-bud loss.
On Hayward sites with historically high levels of Psa, monitor vines now and make decisions on pre-flower girdles. Correct application timing is 30 days before flowering. Use the Psa Risk Model to determine low risk periods for girdling and be sure teams are well supervised and follow good tool hygiene.
Take care to check young development blocks also as young plants are more susceptible and require ongoing proactive management. Consider bactericides in areas with high levels of infection.