Florida has nearly 70 million citrus trees on more than 531,500 acres. Now imagine trying to figure out what pesticide to spray on each of those trees to keep them safe from citrus greening.
University of Florida researcher James Tansey says the answer is as close as your Android smartphone with a new app developed with ZedX, an information technologies company based in Pennsylvania. The free phone program allows citrus farmers to enter in about a dozen variables — like the type of crop, insect pressure, harvest date, previous spray history, and whether the crop will be for fresh fruit or juice and for export or domestic markets — to determine the best pesticide to use. There are also record-keeping options, and the app keeps track of sites with gps.
“It’s free and available now,” said Tansey, who is a post-doctoral researcher at UF’s Institute of Food and Agricultural Sciences Southwest Florida Research and Education Center. He added that the app is currently in the testing phase and UF/IFAS needs growers to give them feedback. “It lets the grower do site-by-site evaluation. Once this testing phase is done and we incorporate feedback, it’ll be available for Apple phones.”
After entering in all the factors, farmers can choose from about 150 different products to kill the Asian citrus psyllid, the tiny insect that carries citrus greening, which is devastating Florida $10.7 billion a year citrus industry. Products are added as they are approved. Farmers can narrow down their product search by cost and effects on beneficial insects (like bees), among other factors.
“The app’s decision-making algorithm will let us apply it to other citrus pests, as well,” Tansey said.
Citrus greening first enters a tree via the tiny bug, which sucks on leaf sap and leaves behind the greening bacteria. The bacteria then move through the tree via the phloem – the veins of the tree. The disease starves the tree of nutrients, damages its roots, and the tree produces fruit that is green, misshapen and unsuitable for sale as fresh fruit. Infected trees can die within a few years; the disease has already affected millions of citrus trees in North America.
When citrus greening disease was first found in Florida in 2005, management programs were adopted by growers to slow the spread of the disease until a sustainable long-term solution could be developed. The approach implemented use of insecticides to control the psyllid, removing infected trees from groves because they served as a source for continued spread of the bacteria, and where trees were removed, replanting with trees grown in certified disease-free nurseries, according to Michael Rogers, interim center director of the UF/IFAS Citrus Research and Education Center.
Adoption of these practices increased the production costs for Florida citrus growers from $800 per acre to more than $2,000 per acre, Rogers said. By August 2008, citrus greening disease was confirmed to be present in every county located within the primary citrus growing region of Florida. Since that time, the disease has spread to every commercial citrus grove in the state, infecting most, if not all, of the fruit-bearing trees at present, Rogers said.
As a direct result of greening disease, the 2015 all orange harvest is predicted to be 96.4 million boxes of fruit. This is down from 240 million in 2003 and is the smallest Florida orange crop since 1966, according to Florida Citrus Mutual, the state’s largest citrus grower organization.