RELATIONSHIP BETWEEN TOTAL POPULATION COUNTS OF GLASSY-WINGED SHARPSHOOTER AND NUMBERS OBTAINED FROM VARIOUS SAMPLING METHODS

• Author(s): Akey, David; Blua, Rick;
• Abstract: Most of our knowledge of the dispersion of Homalodisca coagulata (glassy-winged sharpshooter, GWSS) has been obtained with relative sampling methods in vineyards and citrus orchards (Blackmer et al. 2001, Blua et al 2001, Puterka 2001). Currently, sampling methods are being used to determine timing of pesticide treatments and to judge their efficacy (Blua and Redak 2001, Henneberry et al. 2001). This use implies that the sampling method used relates in a known way to population density. Unfortunately, this is not the case, and some important questions are raised. If a given treatment against GWSS results in zero counts by beat sampling, does that necessarily indicate that there are no GWSS in the area due to the treatments, or could some GWSS be left alive but at density below the detection threshold of the monitoring tool? Could an unknown low density of GWSS be enough to vector PD within or between treated areas? Does the relationship between population sampling precision and accuracy change seasonally? To answer these questions it is imperative to develop a fundamental understanding between actual (=absolute) GWSS density in the field and any relative density estimates derived from various sampling procedures.
• Publication Date: Dec 2002
• Journal: 2002 Pierce's Disease Research Symposium