The state Department of Agriculture announced Thursday that the quarantine area now includes more of Maricopa County and a sliver of southwestern Yavapai County northwest of metro Phoenix.
Quarantine areas already included much of western Arizona as well as a small part of Santa Cruz County.
The Asian Citrus Psyllid can carry citrus greening disease. The insect was first detected in southern Yuma County in 2009, but Arizona officials say they haven't yet detected the disease itself.
The quarantine prohibits movement of untreated fruit and plants that don't have all greenery and stems removed.
Copyright 2015 The Associated Press modified.