Sacramento Valley Orchard Source

These updates are provided as reference information for Sacramento Valley orchard pest and natural enemy activity.

Irrigation Evapotranspiration (ET) Report for the Woodland, Davis, Dixon, and Verona CIMIS stations.

Irrigation Evapotranspiration (ET) Report for Tehama, Butte and Colusa county CIMIS stations.

In prunes, some years are bacterial canker years, while every year is a Cytospora year. Going into this year, we knew the wet/cold conditions could mean that we were headed into a bacterial canker year. However, diagnosing the dieback we are seeing this spring has brought some surprises.

We have been seeing walnut leaves showing browning (necrosis) on the leaf area between the veins in some orchards since about mid-May. Sometimes the leaves will then twist and defoliate in very severe situations.  We call this problem mesophyll collapse and believe it is a physiological problem associated with sudden temperature changes.