By Clint Thompson
Warmer temperatures means San Jose scale populations will begin increasing in peach orchards. Brett Blaauw, assistant professor at the University of Georgia (UGA) College of Agricultural and Environmental Sciences, outlined in the UGA Peach Blog, there is still time to apply delayed-dormant sprays.
If growers are implementing delayed dormant sprays, apply a dormant horticultural oil at a rate of 1.5% to 2% oil to water. Producers should apply the oil:water mixture at high gallonage to maximize coverage. If growers are making such applications to pre-pruned trees, it is important to aim for 150 to 200 gallons per acre, especially in orchards with a history of scale pressure.
If trees have already been pruned, a rate reduction of 100 gallons per acre appears to be effective. Increasing the rate to 3% oil at 100 gallons per acre may achieve effective coverage.
Combining an insect growth regular, such as Centaur or Esteem with the oil can enhance the control of the scale. Combining Venerate with the delayed-dormant oil application has shown to suppress scale numbers compared to just oil alone.
Do not apply oil sprays within two weeks of making a spray that contains sulfur.
San Jose scale is a tiny insect that has a waxy coating that covers and protects the whole body of the insect. It protects them from the environment and from other insects that would eat them.