ps ▁to ▁attract ▁and ▁capture ▁the ▁med f lies ▁to ▁help ▁measure ▁the ▁estimated ▁population . ▁In ▁ 1 9 8 9 , ▁as ▁many ▁f lies ▁were ▁captured ▁as ▁had ▁been ▁captured ▁in ▁the ▁previous ▁fifteen ▁years ▁combined . ▁The ▁greatest ▁concentration ▁of ▁med f lies ▁were ▁found ▁in ▁Orange ▁County ▁and ▁within ▁a ▁triangle ▁linking ▁the ▁eastern ▁edge ▁of ▁the ▁Los ▁Angeles ▁Bas in ▁with ▁San ▁Bernard ino ▁and ▁R ivers ide ▁County . ▁ ▁On ▁December ▁ 8 , ▁ 1 9 8 9 , ▁the ▁state ▁retre ated ▁from ▁its ▁position ▁that ▁the ▁ 1 2 ▁out break s ▁since ▁August ▁each ▁represented ▁" is ol ated ▁inf est ations " ▁that ▁could ▁be ▁easily ▁er adic ated ▁after ▁a ▁panel ▁of ▁scientific ▁advis ers ▁suggested ▁it ▁was ▁not ▁possible . ▁It ▁was ▁instead ▁ordered ▁that , ▁rather ▁than ▁ 1 - 2 ▁aer ial ▁sp ray ings ▁of ▁the ▁inf ected ▁communities , ▁more ▁than ▁a ▁dozen ▁sp ray ings ▁would ▁be ▁necessary ▁over ▁a ▁period ▁of ▁months . ▁In ▁addition , ▁Mal ath ion ▁was ▁no ▁longer ▁used ▁alone , ▁but ▁mixed ▁in ▁a ▁ 4 : 1 ▁ratio ▁with ▁Nu - L ure 0 ▁b ait ▁to ▁attract ▁insect s ▁to ▁the ▁area . ▁ ▁The ▁period ▁of ▁inf est ation ▁stretch ed ▁from ▁July ▁ 1 9 8 9 ▁through ▁November ▁ 1 9 9 0 . ▁In ▁the ▁years ▁since ▁med f lies ▁were ▁discovered ▁in ▁California , ▁an ▁average ▁of ▁$ 2 6