More emerged apothecia were noted at the monitoring sites this afternoon.
Warm temperatures and rain are forecast for this weekend so
development and Monilinia infection may advance quickly.
Many growers were noted spraying this afternoon in
anticipation of the coming wet weather.
Current bud development taken May 1st:
Early varieties (Duke) - 60% F2 stage
Mid-season Varieties (Draper, Bluegold)- 45% F2 stage
Late Varieties (Burlington, Liberty) - 10% F2 stage
Spray timings for Monilinia Blight should target 40% of
buds at F2 stage with active apothecia to give fungicide coverage through
periods of free moisture.
Most Growers will choose to apply with one of the Group 3s for their first application.
There are a couple things we should remember
in order to fine tune our application.
-Group 3's move rapidly into the plant after application
and most have a rain fastness of one hour.
-Group 3's are very locally systemic and windy conditions
during application can effect coverage and decrease effectiveness.
-Group 3's have decent post infection activity and maybe
applied up to 72 hours after an infection period and still provide some
activity. There maybe some risk to relying on post infection activity so growers
should plan on applying ahead of wet infection periods.
-Frost can dramatically increase the susceptibility of buds
to Monilinia infection. This increase in susceptibility can last up to 4
days after a frost. Farm Data Tools weather days shows a frost
in many locations on April 29.
-Infection can occur much more quickly at warmer temperatures. For interest see the table below.
