This information is outdated, since new cultivars have been developed and the disease itself has changed since then. Smith has found the most effective way to control rosette is to apply four fungicide applications at a 10-14 day interval beginning about six weeks before berries ripen and continuing until three days before harvest. She also recommends a fifth application immediately after harvest. Many farmers have been disappointed with fungicidal control of rosette, because they thought spraying would control the disease in that year's crop. The most effective fungicide tested for controlling rosette, caused by the fungus Cercosporella rubi , is benomyl.
Few fungicides are registered and available for controlling blackberry diseases.
Smith plans to evaluate some new fungicides and is also looking more closely at the pathogen and how it infects the fruit. Overcoming this disease offers a high- value crop that costs less to establish than strawberries and blueberries.