An insect responsible for spreading a plant disease that has decimated crops in Brazil and Florida and threatens the industry in California has been discovered for the first time in Marin County.
A single Asian citrus psyllid (ACP) was captured in a Marin County Department of Agriculture trap in Novato on Nov. 22. The insect, originally found in Asia, is about one-eighth of an inch long when in its adult stage, similar in size to the aphid, and has a brown mottled body. Young ACPs are yellowish orange, produce a white waxy substance and are usually found on new plant growth.
The insects spread the deadly plant disease Huanglongbing, better known as citrus greening. The disease, for which there is no cure, is considered the most serious threat to citrus trees worldwide. Florida’s orange production dropped to 68.8 million boxes in the 2016-2017 growing season from 149.8 million boxes in the 2004-2005 growing season, due largely to the disease. Orange production in Brazil has also been hit hard.
“The Asian citrus psyllid has put at risk the viability of the citrus industry in California, and we must take steps to protect it,” said Marin Agricultural Commissioner Stacy Carlsen in a statement.
There are no commercial citrus operations in Marin; however, an estimated 60 percent of California homeowners have a citrus plant on their property.
Carlsen said, “Our mature backyard lemon, orange, mandarin, lime and other fruit-producing citrus trees are grown at family homes throughout the region.”
Carlsen said members of his department have increased the number of insect detection traps deployed within a 50 meter radius of where the ACP was found to determine if there are more such insects present.
Carlsen said he plans to spray citrus plants within the 50 meter radius with a pyrethroid insecticide, which he says has a relatively low toxicity. Although a man-made pesticide, pyrethroids are similar to the natural pesticide pyrethrum, which is produced by chrysanthemum flowers.
Carlsen said before any spraying is done community meetings will be held with affected homeowners. He estimated that at least 17 properties could be directly affected.
To prevent further spread of the disease, the state is establishing a quarantine to regulate the transport of all citrus trees and citrus plant material. This applies mainly to plant nurseries.
In addition, Carlsen said homeowners within the 50 meter radius of the ACP detection are instructed not to move citrus trees, citrus plant parts or foliage of citrus trees.
Marin County Department of Agriculture inspectors will be checking trees in and around the zone where the ACP was detected for signs of infection. Diseased trees must be removed to protect other citrus trees nearby.
ACPs and their eggs are typically found on tender, new leaves. Infected plants have blotchy or yellowing leaves and produce bitter fruit. Citrus fruit from infected trees is safe to eat, although unappetizing.
The disease begins by killing trees’ root system then makes its way up to leaves and fruit. Infected trees have usually lost 30 to 40 percent of their root system by the time owners notice discolored leaves.
Marin residents are urged to be alert for suspected symptoms while tending gardens. Suspicious symptoms can be reported by calling 800-491-1899. For additional information go to CaliforniaCitrusThreat.org.
