The Economic Effects of Pierce’s Disease in California: Preliminary Indications. By Karen M. Jetter, UC Agricultural Issues Center Joseph Morse, UCR Dept. of Entomology Presented at the Pierce’s Disease Symposium San Diego, CA December 15, 2008
Grape growers are now able to treat with chemical pesticides to reduce infestations of GWSS. This has reduced the economic effect of GWSS and PD for grape growers as treatment costs are less than vine death.
Treatment involves an annual soil application of imidcloprid and, when needed spray applications with danitol.
Current Economic Effects Grape Growers – SJV vs Tem
In the San Joaquin Valley imidacloprid is applied during normal irrigations. No separate irrigation is needed.
In the Temecula Valley about 50% of the time a separate irrigation is needed in order to apply imidacloprid when it will be most effective.
As part of the containment program citrus growers voluntarily treat their own groves for GWSS.
In the San Joaquin Valley groves are typically treated once every three years with a fall treatment of Assail and a spring treatment of imidacloprid. Treatments are coordinated by a central agency so that a large continguous entire area can be treated during the same years.