Colder temperatures bring higher Psa risk
Recent cold snaps in most regions have brought welcome winter chill and a good start to leaf drop, but there are also reminders that autumn conditions heighten Psa risk.
For some Waikato orchards -5 degree frosts were recorded last week, and on Psa challenged blocks this sudden dip in temperature has triggered Psa expression. Exudate from girdles and older cankers flag the need to get winter coppers on to rebuild protection after many months of no sprays. Young plants can also come under pressure during cold periods as described in a recent KVH unusual symptoms report.
Development blocks exposed to frosts or wind need special attention as younger growth remains vulnerable to injury, providing opportunity for Psa entry. Good autumn protection is an important part of year-round management of this disease. Forecast risk of ground frosts can be accessed through the KVH Weather & Disease Portal.