By Clint Thompson
Blueberry growers need a more sustainable way of managing diseases. A calendar-based method requires fungicide applications that may not be necessary. The Blueberry Advisory System allows producers to be more efficient in how they manage anthracnose, a key disease growers have to manage every year.
Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist, discussed the system which can be accessed through AgroClimate at http://agroclimate.org.
“Fruit are vulnerable from the time of bloom all the way until they turn blue. Predictive models can be helpful because other than continuing to put out fungicides every week or two throughout that period of time, really, we don’t have a way to know when the fruit are likely to get infected,” Oliver said.
“The predictive model for anthracnose is a way to predict when infections are more likely to occur. Maybe we can target some of our applications of chemicals to those times when the fruit are more vulnerable to infection. We can limit our overall number of applications, maybe save some money and also reduce some resistance development. That’s the goal.”
System Background
A total of 19 UGA weather stations have been incorporated into the Blueberry Advisory System. The system was adapted from the Strawberry Advisory System to predict the risk of infection of blueberry with anthracnose. It is based on weather parameters, mainly leaf wetness and temperature.
Model information will help blueberry producers extend spray intervals in some years. The calendar system means growers spray for anthracnose every 10 to 14 days from bloom to harvest. The model system delays additional sprays until moderate or high risk conditions are present.
It also targets the use of the most effective chemistries to the highest infection risk periods. The current practice means growers use the most effective chemistries whenever possible. The model information uses excellent or very good materials when only high or moderate risk conditions are present.
“In some years when the conditions are just right for the disease, there’s not going to be a major gain from these, but in years where maybe it’s drier and there’s lower risk of infection, when weather parameters aren’t good for the pathogen, we can learn that from using the tool,” Oliver said. “We can say we’re going to delay our sprays or take longer intervals between our sprays. We can get by with less and have just as good of control.”