Asian Citrus Psyllid

First spotted in Palm Beach County, Florida in 1998, the Asian citrus psyllid is rapidly becoming a threat to citrus and other close relatives throughout select regions of the United States. Its movement is being closely tracked by the USDA and Cooperative Extension offices as a result. First signs of the psyllid and/or Citrus Greening Disease (Huanglongbing) should be reported to your local county extension service. Much of the spread of the Asian citrus psyllid is attributed to the transportation of infested nursery plants, so close inspection of desirable plants should be done before purchase and transport. Quarantines have been and continue to be put in place where the pests are identified. While the psyllid can cause significant cosmetic damage to plants, it is the disease the psyllid vectors, called Citrus Greening, that is most threatening to orchards, nurseries and home growers alike.

Asian Citrus Psyllid Life Cycle:

Eggs are identified by their bright yellow-orange color and almond shape. They are often found in the creases of feather flush leaves or on the tips of growing shoots; however, the number of eggs laid depends on the host plant and seasonality as ample new growth is needed for nymphs to feed and mature. Eggs hatch in as little as 4 days varying with warmer or cooler temperatures. Asian citrus psyllids mature through five nymph stages before reaching adulthood and will be concentrated on or near new growth sites. Nymphal stages share similar coloring to the eggs and feed exclusively on new growth as mature leaves harden to the point feeding is impossible. Once they reach adulthood, Asian citrus psyllids are brownish in color and feed on young and old foliage. Adult life spans range from 1-2 months and are heavily influenced by temperature and host due to the fluctuations in flush timing and frequency. Under optimal conditions, the Asian citrus psyllid can complete 30 generations per year.

Damage Symptoms & Identification:

Asian citrus psyllids damage resembles that of other psyllid species with leaf curling/twisting and reduced plant vigor common; however, the paramount concerns surrounding the Asian citrus psyllid are the transmission of Huanglongbing disease (Citrus Greening disease) and the stunting of new growth due to the damage inflicted by nymphs. The nymphs inject a toxin into the leaf tissue as they feed causing leaf curl. In high population areas, the injected toxin burns new growth and can kill new shoots. Huanglongbing disease shows up as asymmetrical yellowing of leaves in a section of the canopy, which differs from the more symmetrical yellowing along veins caused by nutrient deficiencies.

Asian citrus psyllid nymphs excrete honeydew while feeding like aphids, whiteflies and some species of scale. This sticky substance accumulates on leaves and promotes the growth of fungal diseases like sooty mold. The high sugar content of the honeydew often draws the attention of ants that will protect pest colonies that produce it.

Monitoring & Controlling Asian Citrus Psyllid:

Notify your local county extension service immediately if Asian citrus psyllids are detected. The following control measures are for the Asian citrus psyllid only. Once a tree is infected with Huanlongbing disease, there is no cure.

  • If you are in a region where the Asian citrus psyllid is a known pest or is being monitored by authorities, do your part and set up traps in your growing space. There are specialized Asian Citrus Psyllid Traps that come with a pheromone lure and are useful in a backyard or orchard setting.
  • Inspect the new growth of any citrus you have for signs of psyllid damage: waxy deposits, honeydew, sooty mold, ant activity and twisted leaves. The presence of adults and/or egg masses indicates a need for active control needs to be taken.
  • Apply Grandevo and/or Venerate XC starting early in the growing season to kill nymph and adult psyllids. Both of these OMRI listed biopesticides limit impacts on beneficial insects in the growing area.
  • If Huanglongbing disease is identified, chemical control should be taken in addition to quarantine measures as beneficial insects do not provide adequate control to halt the spread of the disease.

    • Horticultural Oils will suppress psyllid feeding by making it more difficult to pierce the leaf surface and coating psyllids they come in contact with. Use JMS Stylet Oil to limit risk of phytotoxicity.
    • Neem Oil is a contact insecticide and acts as a feeding/growth inhibitor to all stages of psyllids. In addition, neem helps to control fungal diseases.
    • In the case of severe infestation, consider Pyrethrin and/or Azadirachtin insecticides. They can be used as standalone sprays or in an alternating spray program depending on your needs.
  • Inspect all plants and fruit before transporting them. If pests or disease symptoms are found, dispose of the affected material immediately.