FORECAST DISCUSSION: Thursday, September 28:
*** September 27 Disease Update: First reports of downy mildew from Wisconsin and Illinois. *** Our thanks to Dan Egel in Indiana.... who confirms outbreaks of downy mildew in Walworth County, WI and McHenry County, IL. These counties are adjacent to each other in the southeast WI / northeast IL region. Other information indicates that many other growers in this area have downy mildew, and disease has been present since the beginning of September. As with the recent NJ report..... since disease has been present for several weeks, it is likely that other growers in the region have downy mildew. Since these new outbreaks are only 25 miles apart and disease is present elsewhere in the area, we have selected Lake Geneva as a central location from which to launch the forecast trajectories.
*** September 20 Disease Update: We have our first reports of downy mildew from Virginia and New Jersey *** Steve Johnston in NJ informs us of a serious outbreak of downy mildew in the southern part of the state. Disease was first observed on August 21 on summer squash. During the past month, downy mildew has spread across Salem, Cumberland, and Gloucester counties in southern NJ. It has appeared on the majority of cucurbits grown in that area, primarily pumpkins and muskmelons. Sam Alexander in VA reports that downy mildew has been discovered in Accomack County. This county lies adjacent to Wicomico County, MD in the southern end of the DelMarVa peninsula. Given the proximity of these new reports to the current known source in Wicomico County (Salisbury, MD), they will be included in the forecasts for that general area. A trajectory from Bridgeton, NJ will be included in the forecasts in order to bracket the DelMarVa/southern NJ region. PLEASE NOTE: With disease having been present for at least one month in this region, it is likely that downy mildew is present in other nearby areas, particularly to the north and east of these known sources. Growers concerned about downy mildew should check their plants for signs of disease as soon as possible.
*** Mostly benign weather for this weekend. *** Strong high pressure will govern the weather over much of the eastern U.S. for the next few days. Other than a chance of showers near FL or the Southeast coast on some days, dry, unfavorable weather is expected. A system that may develop near the Bahamas and pass close to the Southeast coast later in the weekend will be watched closely, with updated forecasts posted if needed. Low Risk for growers near all the known sources through Sunday, with the exception of central FL where there is Moderate Risk of disease development each day.
TK
Images courtesy of Tom Isakeit
Current Sources:
Previous Sources:
Ciudad Mante, Mexico
Colima, Mexico
Houston, Texas
This service is provided by the North Carolina State University departments of Plant Pathology and Marine, Earth, and Atmospheric Sciences.