Recent infection periods

Cedar-apple rust galls are still actively supplying inoculum for foliar infection, but most fruits should now be resistant to quince rust. Apple scab and cedar-apple rust infection periods were recorded at our AREC May 18-19 (16 hours wetting with only 0.01 inches of drizzle at 56-64°), May 19-20 (10 hours wetting with 0.09 inches of rain at 63-67°), and last night, May 22-23 (18 hours wetting with 0.94 inches of rain at 62-70°). Secondary "sheet" scab is now common on trees that were not protected two weeks ago, May 6-11. 

As of today, May 23, we have had 29 dry weather apple powdery mildew days since spores were first released Apr 11.

For purposes of predicting the development of the sooty blotch and flyspeck (SBFS) fungal complex, we record accumulated wetting hours, starting 10 days after petal fall. With the extended bloom period this year, the petal fall date was somewhat subjective, but we have settled on May 3 as our petal fall start date. So the start of wetting hour accumulation will be from May 13, 25 days later than last year. As of Monday morning, May 20, we had accumulated 26 wetting hours toward the 250 wetting hour threshold for specific treatment against the SBFS fungal complex. Last year we reached the 250-hr threshold May 25.