Mani Skaria, Ph.D.
Founder & CEO, US Citrus, LLC
Professor & Citrus Scientist (Retired), Texas A&M University-Kingsville
Name psyllid comes from the word psylla means plant lice. The Asian citrus psyllid (ACP), scientifically called Diaphorina citri is a pest and a vector that has caused a rapid decline of the citrus industry in the state of Florida.
Difference between a pest and a vector: A pest is a living organism that causes nuisance and competition for food and water. Insects, mites, weeds etc. are common pest found in your backyard. Pest can be numerously occupying a small area. A pest would be called a vector when it carries a harmful pathogen. For example, ACP is a pest when it has no harmful bacterium in it. Whereas, it is a vector also when it carries the bacterium that causes the greening disease (also, called huanglongbing or HLB.
The adult ACP (top figure)
- Three to four millimeter long
- With a brown, spotted body
- Feeding position on leaves at an angle
- White, waxy secretions of the nymph is an indicator of ACP
All pictures: Source University of Florida and USDA-ARS.
The Nymph undergo five instars or stages; sizes range from 0.25 mm (1st instar) to 1.7 mm (5th instar).
See figure bottom.
Eggs are 0.3 mm, elongate, almond-shaped
One adult female lay about 800 eggs during its life of several months. It will take 15 to 50 days for a cycle.
Control (Non-chemical approach for homeowners)
- Cut off infected branches, carefully place them in a plastic bag, tie it and dispose of it. This will physically remove a lot of future adults
- Contact your local university extension department for sources of natural enemies such as syrphids, chrysopids, coccinellids, parasitic wasps such as Tamarixia radiata.
- The author has successfully controlled ACP infestations on his backyard citrus by dusting diatomaceous earth. (short-term strategy needs to be repeated).
Why Should Psyllids be controlled?
Apart from being a pest, psyllid is a vector of citrus greening disease or huanglongbing (HLB). This disease can make your tree useless as a patio plant, if you do not take control measures – ACP control and proper nutrition program for the tree to resist infection
Halbert SE, Núñez CA. 2004. Distribution of the Asian citrus psyllid, Diaphorina citri Kuwayama (Rhynchota: Psyllidae), in the Caribbean basin. Florida Entomologist 87 (3).
Hall DG. 2006. A closer look at the vector: Controlling the Asian citrus psyllid is the key to managing citrus greening. Citrus & Vegetable Magazine 70 (5): 24-26.