Late blight has been confirmed in SWFL
Glades Crop Care reports their first confirmed detection of late blight on tomatoes. Race identification is ongoing.
Late blight is caused by the fungus-like 'oomycete' Phytophthora infestans, which is a pathogen of potato and tomato. This disease can spread quickly and devastate a tomato or potato field within a few weeks, if not properly controlled.
The disease thrives under cool and wet conditions. Temperatures between 50 and 80 °F combined with moist conditions such as rain, fog, heavy dews, or relative humidity above 90 percent are conducive for disease development. Night temperatures in the mid-fifties with daytime temperatures from the mid-fifties to mid-seventies are ideal for this disease.
Since the disease can spread rapidly, growers should scout their fields thoroughly each day, especially when these conditions conducive to disease development prevail.
Timing is critical! Begin a spray program with fungicides if late blight is in your area or weather conditions are suitable for late blight development.
Identification, pictures, and management information from the South Florida Pest and Disease Hotline can be found here: https://mailchi.mp/f49bebfe1e47/late-blight. Special thanks to Gene McAvoy for the summary information that continues to be relevant.
Additional pictures for identification can be found here: https://plantpath.ifas.ufl.edu/u-scout/tomato/late-blight.html.