Determining latent brown rot infection
Growers can now use a simple freezing technique to determine if they have latent brown rot infections in their orchards.
The University of California’s Dr. Themis Michailides, who helped develop the Overnight Freezing Incubation Technique, said that growers can perform the test by collecting a representative sample of immature fruit from the orchard and surface sterilizing them in a chlorine solution for 20 minutes. The fruit is then washed with sterile distilled water, placed on a sterilized plastic screen in a container with water at the bottom, and frozen for ten hours. The container of fruit is then placed at room temperature for five days. After five days, fruit covered with brown rot spores can be recorded and the incidence calculated as a percentage of the fruit in the sample.
In the future, he believes that portable molecular instruments will be affordable and simple protocols will be available for in-field diagnosis by growers and pest control consultants.
Michailides and his colleagues are working to develop a number of molecular methods that would be faster, more reliable, and more efficient than conventional disease management techniques—some of which take up to 21 days before results are known.