Published: February 14, 2011
CLEMSON — A Clemson University plant disease scientist received $850,000 to help growers deal with strawberry diseases. Guido Schnabel, an Extension Service plant pathologist and state specialist for fruit diseases, is participating in a regional project based at the University of Florida.
A four-year, $2.9 million USDA National Institute of Food and Agriculture grant supports efforts to forecast outbreaks of two fungal diseases threatening the nation’s $2.1 billion strawberry crop. The funds will help the multi-university team expand its program to fight Anthracnose fruit rot and Botrytis fruit rot.
It was Schnabel’s work with another South Carolina crop that made his participation in the strawberry project useful. His research on peaches and brown rot disease contributed to the development of a way for growers to rapidly detect and manage fungicide resistance. Working with University of Georgia plant specialists, he developed a diagnostic toolkit now used by county agents to help growers select the most effective fungicides for sustained disease control.
“We’ve developed a kit that will enable growers to determine the fungicide resistance profile in their respective areas,” Schnabel said. “We collect diseased fruit, conduct a sensitivity test, and within three days, using that kit, we can determine what works and what doesn't. This information allows science-based, location-specific disease management.”
But managing emerging fungicide resistance in strawberries is just one aspect of the proposed research. Florida growers often spray fungicides on their plants weekly as a preventive measure, according to researchers. With the help of a disease forecast system to predict high risk of infection by analyzing air temperature and plant leaf wetness, the number of total applications can be drastically reduced, said University of Florida plant pathologist Natália Peres, the project leader. Experiments so far have shown that growers can potentially reduce fungicide use by half without compromising disease control.
The grant will enable the team test the system in other strawberry-producing states, including South Carolina, with the added component of monitoring fungicide resistance and advise growers of alternative fungicide options.
Florida is second to California in strawberry production. Oregon and North Carolina growers also have substantial acres planted in the fruit. In South Carolina, strawberries are a small specialty crop totaling about 700 acres.
Botrytis fruit rot is a widespread fruit disease. Affected fruit becomes light brown. The disease germinates in the spring and infects bloom parts, then moves into the fruit and may rot it immediately or be dormant until the fruit ripens. The disease is most severe in wet weather.
The Anthracnose fungus causes round, brown, firm sunken spots on the fruit. Once the disease is present, removal of diseased plant material is essential. Mulching and spraying fungicides every five to seven days can save 50 to 70 percent of the harvest.
The Specialty Crops Research Initiative was established by the 2008 federal farm bill. It provides funding for research and extension on fruits and vegetables, tree nuts and horticultural and nursery crops. Nationwide, the specialty crops industry is valued at about $50 billion annually, according to the USDA.