FAQ's about Invasive Species in California
What are invasive species?
Where do invasive species come from?
How do invasive species establish?
Why do some species become invasive but other species do not?
Invasive Citrus Pests
Asian Citrus Psyllid
Asian citrus psyllid is an efficient vector of the citrus disease huanglongbing (HLB), previously called citrus greening disease, which is one of the most destructive diseases of citrus worldwide. In North America, the psyllid vector...
Asiatic Citrus Canker
Asiatic citrus canker is a widespread bacterial disease in Asia and in certain other citrus-growing regions of the world, but it was eradicated from the U.S. after its introduction in the early part of this century. New infestations...
Black Scale
In California, black scale is a periodic pest of citrus in southern California and a consistent pest of olives in the San Joaquin Valley. It was introduced into the United States and California sometime before 1880. It now...
Brown Citrus Aphid
The brown citrus aphid is an insect pest of all citrus varieties. The brown citrus aphid infests the stems and new leaves of citrus trees and in addition to feeding damage, it is a highly efficient vector of citrus tristeza virus...
California Red Scale
California red scale was introduced into California between 1868 and 1875, apparently on citrus seedlings from Australia. The scale insect is native to Southeast Asia but has been transported on citrus seedlings to all...
Citricola Scale
In California, citricola scale is a serious pest in San Joaquin Valley citrus when broad-spectrum pesticide use is reduced. It was also a serious pest in the inland areas of southern California until 1935, when an...
Citrus Greening (Huanglongbing)
huanglongbing (HLB), previously called citrus greening disease, is one of the most destructive diseases of citrus worldwide. Originally thought to be caused by a virus, it is now known to be caused by unculturable...
Citrus Leafminer
Citrus Leaf Miner rapidly became a significant pest, with infestation rates of up to 90% in some areas in Florida being observed within the year of introduction. By 1995, the citrus leafminer was discovered in...
Glassy-Winged Sharpshooter
The Glassy-winged Sharpshooter (GWSS), likely introduced from the southeastern U.S. as eggs on nursery stock, was first observed in Orange and Ventura counties in 1989. It has a large plant-host range and is especially...