Scab

      Just a few quick notes:

1) The current forecast (Thursday afternoon) suggests there may be a window of calm winds and a break in the rain late Friday – early Saturday.  After that, there is chance of more showers on Sunday into Monday. 

 

2) Many Maine orchards are in a situation where a post-infection scab fungicide is needed to suppress infections that may have begun after previous fungicide coverage was washed off May 22-23.  If the ground in the orchard is drained enough to allow travel spray equipment, it would advantageous in those orchards to apply a post-infection fungicide as soon as wind conditions allow good coverage and drying conditions will allow spray to dry and set before being re-wetted.

 

3)  Unless you have reason to suspect sterol inhibitor resistant scab in your orchard, one of the sterol inhibitor fungicides (Nova, Rubigan, Procure) would be a better choice for arresting developing scab lesions than one of the strobilurins (Sovran, Flint).  This is because the sterol inhibitors can reach back a greater number of hours for postinfection control under the temperature conditions we have had this week.

 

4) The new strobilurin fungicide Pristine is similar to Sovran and Flint with regards to postinfection scab control.  Pristine is best reserved for late summer use to take advantage of its prolonged efficacy for preharvest suppression of flyspeck and summer rot fungi.