SUBJECT: PRELIMINARY MONITORING RESULTS OF THE EIGHTH AND NINTH SPINOSAD AERIAL APPLICATIONS FOR MEXICAN FRUIT FLY ERADICATION IN VALLEY CENTER, SAN DIEGO COUNTY (STUDY 216)

quantifiable at both sites, 1.59 and 0.41 µg/ft 2 , comparing to the 0.12 µg/ft 2 average of previous applications. None of the surface water contained detectable spinosad residues. Six tank mix samples were collected during the eighth application and spinosad concentrations ranged 0.0084% to 0.0098% with average of 0.0088%. Three tank mix samples were collected for the ninth application and concentrations ranged 0.0095% to 0.0099% with average 0.0096%. These averages were 110% and 120% of the target concentration (0.0080%). No organophosphates, carbamates, and chlorinated hydrocarbons were detected in all the tank mix samples.