Citrus Pest Management

There is a wide range of pests and diseases that can damage citrus and threaten tree and crop health if not managed appropriately. Since the early 1900s, California citrus growers have used an Integrated Pest Management (IPM) approach to control pests in the grove.  IPM incorporates the use of beneficial insects, pesticides, and other management tools to effectively control pests in the most environmentally conscious way possible.

The University of California is a leading source of information about pests and diseases affecting California citrus and Integrated Pest Management.  Visit the UC IPM website to learn more.

 

Major Citrus Pests of Concern in California

Asian citrus psyllid – Diaphorina citri

The Asian citrus psyllid (ACP) is an invasive insect that can carry the lethal citrus plant bacteria Huanglongbing (HLB).

The Asian citrus psyllid only attacks citrus and closely related plants in the Rutaceae family. When the psyllid feeds, it injects a toxin that causes leaves to twist and die. More importantly, it is a vector of the bacterium Candidatus liberibacter asiaticus that causes Huanglongbing disease (HLB), a deadly and incurable citrus tree disease. Symptoms of HLB include yellowing of leaves and misshapen, discolored, and underdeveloped fruit.

The only defense against HLB is to control the Asian citrus psyllid. Citrus growers are highly encouraged to participate in localized area treatments to keep populations from spreading.

Regulations and quarantines are in place to restrict the movement of bulk citrus loads to prevent HLB from spreading.

Visit CitrusInsider.Org or the California Department of Food and Agriculture website for more information about ACP and HLB, treatment recommendations, and applicable regulations.

Resources
University of California KAC Citrus Entomology
Asian Citrus Psyllid Distribution and Management
UC Pest Management Guidelines – Controlling the Asian citrus psyllid
For more information on the biology of the psyllid, see ANR Publication Asian Citrus Psyllid and Huanglongbing.

Fuller Rose Beetle – Naupactus (Asynonychus) godmani

Fuller rose beetle adult females emerge from the ground year round, but the heaviest emergence is from July to October. There are no males. Female beetles lay eggs under the calyx of citrus fruit and other cracks and crevices. The neonate larvae drop to the ground and feed on roots for 6-8 months, after which they pupate and then emerge as adults the following year.

Resources
University of California KAC Citrus Entomology
UC Pest Management Guidelines – Controlling Fuller Rose Beetle

California red scale – Aonidiella aurantii

California red scale starts its life cycle as a crawler that emerges from a female scale. The crawler finds a leaf, twig or fruit to settle down on and inserts its threadlike mouthpart. If female, the scale molts twice and matures through 2 nymphal instars into the virgin female stage that is receptive to mating with a male. If male, the scale molts from 1st to 2nd instar, then prepupa, pupa, and finally becomes a winged adult. The entire lifecycle takes six weeks to complete.

Resources
University of California KAC Citrus Entomology
UC Pest Management Guidelines – Controlling California Red Scale
For more information on the lifecycle, see ANR publication 21529 CRS lifecycle Pub 21529.

Bean thrips – Caliothrips fasciatus

Bean thrips lays its eggs and completes its lifecycle in weeds and other plants near citrus orchards. The adult bean thrips migrate into citrus orchards in October-November, when the weed hosts die or the field crops it infests are harvested. Bean thrips seek out well-protected areas to overwinter, such as the navel of oranges where they contaminate harvested fruit. Bean thrips is not considered a pest of citrus in California. However, other countries such as Australia that do not have this pest consider it a quarantine pest of significance, requiring a preclearance program and fumigation of infested loads. Bean thrips are found throughout California citrus.

Resources
UC Pest Management Guidelines – Controlling Bean Thrips

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