There are many diseases that can threaten the survival of a potato crop. A prime example is early blight. Research completed in 2013 by University of Idaho Extension showed that crop losses due to early blight can exceed 20 percent if left uncontrolled. The same research showed that in potato-growing regions, the use of fungicides can help decrease these crop losses to less than 5 percent.
When determining how to control diseases like early blight, growers should plan early and consider fungicides as a part of their disease management plan.
“To best prepare for any diseases that may affect their crop, potato growers should develop a fungicide plan prior to the season, so that they are prepared to make timely applications,” says Curtis Rainbolt, a BASF technical service representative based in Idaho. “Endura fungicide is a product we recommend growers use for control of early blight and ultimately to help prevent crop losses.”
When such a high risk is associated with uncontrolled early blight, growers should carefully monitor their crop for signs of this and other diseases.
Timing It Right
Although its name would imply that early blight appears early on in the growing season, it rarely does and often appears on mature foliage. Growers should keep this in mind and try to time applications of fungicides to their crop carefully.
During the vegetative stage, application of foliar fungicides for early blight control is typically not necessary, as plants are still relatively resistant. Fungicide application that occurs too early could have minimal to no effect on the spread of early blight. Instead, growers should wait for the optimal time to apply fungicides.
While growers should continually monitor their fields for signs of disease, fungicides should be applied preventively to avoid disease development. Rainbolt recommends applying fungicides on a tight spray schedule of five to 14 days depending on the location and disease pressure, in accordance with the label. This is especially important in weather conditions that can be breeding grounds for disease-causing fungi. In the case of early blight, alternating wet and dry periods favor disease production.
“A potato crop can face a variety of issues each year that threaten its health and yield potential, including diseases brought on by adverse weather conditions,” says Rainbolt. “Growers should control what they can and protect against what they cannot. Growers can help manage these issues by controlling yield-robbing diseases through fungicides.”
Managing Resistance
While using fungicides to control early blight in a potato crop, growers should be mindful of the products they choose and the management techniques they implement to fight fungicide resistance.
“One practice we recommend growers follow to fight resistance is beginning their spray programs with the most effective fungicides,” says Rainbolt. “Growers should use tank mixes of protectants like chlorothalonil or mancozeb-based fungicides with Endura fungicide.”
Endura has a single mode of action that allows for tank-mixing flexibility to further manage fungicide resistance development.
Other practices Rainbolt recommends growers follow to manage fungicide resistance include limiting the number of sprays with the same mode of actions and rotating different modes of action in spray programs.
Determining the Best Plan
Use of fungicides to control early blight should exist within a comprehensive integrated disease management plan. Practices such as rotation with non-host crops, avoiding irrigation in cool, cloudy weather, and the removal of infected plant debris all help reduce the risk of early blight inflicting a grower’s potato crop.
“Growers can work with their local chemical representative to determine how fungicides can work within their integrated disease control plan,” says Rainbolt. “Our reps recommend Endura fungicide to be included in a grower’s disease management plan so they can get ahead of early blight while preserving their crop’s yield.”
For more information, contact a BASF representative or visit www.GrowSmartPotatoes.com. Always read and follow label directions.
Endura is a registered trademark of BASF.