Recent extended wetting periods

This past week we had three extended wetting periods and more than 2.5 in. of rain (as of 4 PM today, but we are really not complaining about the rainfall): Jul 15-16, 10 hr wet at 70°; Jul 18-19, 8 hr wet at 71°; Jul 19-20, 17 hr wet at 72°. In the past two weeks we have gotten more than 4 inches of rain, which would have eroded most protective fungicide residues, adding considerable rot pressure on apples and other fruits. Cumulative wetting hours now stand at 572, the highest total for this time of the year since 2003, and the fourth highest total since 1994.


There have been several reports of rots appearing where was earlier fire blight infection. This should be expected because any dead twigs can be quickly colonized by several rot fungi, leading to a build-up of inoculum and subsequent infection under the warm and wet conditions such as have occurred recently.


Scout for sooty blotch and flyspeck in lower elevation areas where you typically see these problems first, and make appropriate management adjustments as needed.