Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Spatial Population Dynamics and Overwintering Biology of the Glassy-Winged Sharpshooter in California's San Joaquin Valley.

Authors
item Johnson, Marshall - UNIV OF CALIF-RIVERSIDE
item Daane, Kent - UNIV OF CALIF-BERKELEY
item Groves, Russell
item Backus, Elaine

Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: October 5, 2005
Publication Date: December 5, 2005
Citation: Johnson, M., Daane, K., Groves, R.L., Backus, E.A. 2005. Spatial population dynamics and overwintering biology of the glassy-winged sharpshooter in California's San Joaquin Valley. Proceedings of the 2005 Pierce's Disease Research Symposium. p. 113-116.

Interpretive Summary: Climate appears to play a significant role in the geographic distribution of diseases caused by Xylella fastidiosa (Xf) as well as the establishment and distribution of the glassy-winged sharpshooter (GWSS). We determined the effects of constant temperatures for various exposure times on the survival of GWSS adults under three different conditions: water-only, no water or host plant, and host plant. Adults survived the longest at 15°C when provided water only, with the shortest longevities at 0 and 40°C. When adults were provided with a preferred host plant (‘Frost Eureka’ lemon), adult survival significantly decreased at low temperatures while survival between 15-30°C (average > 68%). These findings suggest that mortality at low temperatures could result from starvation or lack of feeding. Comparing host plant presence and absence, 100% mortality occurred at 3, 21, 24 days at 0, 5, and 10°C, respectively. This implies that GWSS adults cannot feed on a host plant at low temperatures (0-10°C), and further suggests that the threshold temperature for feeding is between 10 and 15°C. Results from these experiments will be coupled with weather data to help to define where GWSS can be expected to persist in non-infested areas of California and identify where continued management efforts can be directed to limit further introductions.

Technical Abstract: The purpose of this project is to define specific environmental constraints that influence GWSS population dynamics and overwintering success. Experiments were conducted to determine effects of constant temperatures on the survival of GWSS adults for various exposure times under three different conditions: water-only, no water or host plant, and host plant. When only provided water, adults survived the longest (16.3 ± 1.8 days) at 15°C, with the shortest longevities at 0 and 40°C (1.5 ± 0.1 and 2.5 ± 0.3 days, respectively). Overall, the longevity patterns implied that lack of a suitable host plant would result in greater reductions in survival at higher temperatures. When adults were provided with a preferred host plant (‘Frost Eureka’ lemon), percent adult survival was significantly influenced by temperature and exposure time with a significant interaction between time and treatment. Unlike the initial study where only water was provided, adult survival decreased drastically at low temperatures (0-10°C), while survival between 15-30°C averaged > 68%. Findings suggest that mortality at low temperatures could result from starvation or lack of feeding, and the critical threshold temperature required for ingestion lies between 10-15°C. In a third experiment comparing host plant presence and absence, 100% mortality occurred at 3, 21, 24 days exposure at 0, 5, and 10°C, respectively. This implies that GWSS adults cannot feed on a host plant at low temperatures (0-10°C), and further suggests that the threshold temperature for feeding falls between 10 and 15°C. These experiments along with additional ones on feeding activity are continuing (consider to omit). Results from these experiments will be coupled with climatological data to help to spatially define where GWSS can be expected to persist in the agricultural landscape and identify where continued management efforts can be directed to limit introductions into currently non-infested areas.

Last Modified: 10/20/2014
Footer Content Back to Top of Page