Asian Citrus Psyllid

The tiny Asian citrus psyllid is costing orange growers billions of dollars in losses, and it might be on your trees!

Symptoms of citrus greening disease carried by Asian citrus psyllids (Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, bugwood.org) CC BY 3.0

The Asian citrus psyllid (Diaphorina citri) arrived in North America from Asia or India in 1998. The insect feeds on the sap found in leaves and stems of citrus trees. As they feed, they produce large amounts of honeydew (sugary bug poop). This honeydew is a popular food of ants and the sooty mold fungus. That wouldn’t be a serious problem, by itself. The situation is made far worse because the Asian citrus psyllid carries a bacteria that causes a devastating disease called huanglongbing (HLB). Also known as citrus greening, HLB is a vascular disease that kills trees and there is no cure. Trees infected with citrus greening must be destroyed.

Asian citrus psyllid identification

This pest is about the size of a grain of rice. It is a mottled brown color with a light brown head. The wings have a dark brown band around the outer edge and look as though they are being held up and behind the insect when at rest. Most adults have a dusty appearance. Nymphs are yellowish orange with long, white waxy secretions, called tubules. Tiny, almond-shaped eggs start out pale, turn yellow, and then orange just before hatching. [I couldn't find a photo I could use, so Google it.]

​Asian citrus psyllid lifecycle

Adult females lay between 300 and 800 eggs. These eggs are laid on new growth, on shoot tips and between unfurling leaves. Nymphs go through five instars. The entire lifecycle takes from 15 to 47 days, depending on conditions. There can be up to 10 generations a year. [I don’t know about you, but that’s some crazy math. If there are any mathematicians reading this post, I would love to read in the comments just how many offspring that can mean!]

Host plants and signs of infestation

You can tell by the name that these pests feed on oranges, lemons, limes, and grapefruit. They have also been found feeding on kumquat (Fortunella sp.), Indian wood apple (Limonia polyandra), jasmine, citron (Citrus medica), pummelo (Citrus x maxima), mock orange, Cape chestnut, Bengal quince (Aegle marmelos), and others.

There are several signs of infestation that all citrus tree owners should watch for on a frequent basis:

• tiny yellow eggs tucked into new leaf growth
• deformed or blotchy new leaves
• new shoots look burned
• thin, white waxy tubes on new leaf growth
• actually seeing the insect
• leaf mottling
• yellow shoots
• misshapen internal fruit structure
• corky leaf veins
• twig dieback
• small, hard fruit, with a bitter taste

Financial impact of Asian citrus psyllids

Some pests are more costly than others. This one tops the list. Infection of citrus trees around the world is wiping out entire regions of citrus growers. Companies that sell citrus products are paying more for domestic citrus, and they must also buy citrus products from other countries, causing the loss of local jobs. Also, over $1 million a year is being spent on public education, to slow the spread of this problem. This means even higher prices. The reason for this educational investment is that there are more citrus trees in backyards than in commercial orchards. Uninformed homeowners are far more likely to allow this pest to expand its range even further.

Halting the spread of citrus greening

Learning what to look for is one of the best ways to help slow this threat to citrus. These tips will go a long way toward preventing the spread of this disease:

• Do not accept tree cuttings from uncertified sources.
• If asked, allow the State Dept. of Food & Agriculture to hang a trap on your property.
• Do not transport leaves or stems out of the quarantine area.
• Scrub fruit thoroughly, especially around the stem base, before removing it from a quarantine area.

Please read my post on huanglongbing disease and find out if you are in or near a quarantine zone. It is up to citrus tree growers everywhere to help combat this devastating pest.

​If you suspect or see signs of the Asian citrus psyllid or huanglongbing disease, immediately contact the CALIFORNIA DEPARTMENT OF FOOD AND AGRICULTURE HOTLINE: 1‐800‐491‐1899, or your local Department of Agriculture.