Kearney Agricultural Research and Extension Center
University of California
Kearney Agricultural Research and Extension Center

Homeowner Information

Residential ACP Management Strategy

The Asian citrus psyllid is widely established in urban and suburban areas throughout Southern California (Asian Citrus Psyilld Risk Map). Large-scale eradication of ACP in these environments is not feasible. Rather, the goal is to reduce psyllid populations enough to slow the establishment and spread of Huanglongbing disease in the region.

 

ACP management for residential citrus includes:  

1. Natural enemies.  Releases of a parasitoid wasp, Tamarixia radiata, in urban and suburban areas of Southern California are ongoing. This wasp, which poses no threat to people, attacks young stages of only ACP. Under ideal conditions it can reduce ACP populations. So far more than 50,000 wasps have been released at more than 300 sites throughout the region. Although it is too early to know how effective the wasp will be, the hope is that it will at least partially help control psyllid populations.    

2. Insecticide treatments.  Because Tamarixia is not yet widely established and is unlikely to provide control of the HLB disease, robust protection of citrus trees will require some form of chemical control. The most effective treatment for ACP is a combination of Tempo spray followed by a soil drench of systemic imidacloprid (Merit) applied by a licensed applicator. Homeowners can purchase their own foliar sprays (Sevin, Malathion) and imidacloprid (Bayer Advanced Fruit, Citrus & Vegetable or Monterey Fruit Tree & Vegetable Soil Drench).  Sevin or Malathion should be applied when psyllids are observed. The imidacloprid soil drench should be made during summer or fall when roots are active, but since it lasts 1-2 months it need not be applied more than 2-3 times a year.  Softer options include horticultural oils and insecticidal soaps. However, these products only kill psyllids on direct contact and the residues are short lived, so they must be applied frequently (every 7-10 days) if psyllids are present. Approximate costs of treatments can be found here (link economic section).

Asian Citrus Psyllid Risk Map

Click map for Interactive Mapping Website
Click map for Interactive Mapping Website

Treatment Considerations

-only apply pesticides if psyllids have been observed

-only apply insecticides to host plants of psyllids (citrus and closely related hosts)

-always follow label instructions for the safe and effective use of the product

-avoid using insecticides during blooming periods to limit impacts on pollinators

-good coverage, including undersides of leaves, is important for foliar sprays

Asian citrus psyllid nymphs and adult (inset) on citrus shoot. Photo: M. Lewis, UC Riverside
Asian citrus psyllid nymphs and adult (inset) on citrus shoot. Photo: M. Lewis, UC Riverside
Tiny stingless wasp Tamarixia.  Photo: M. Lewis, UC Riverside
Tiny stingless wasp Tamarixia. Photo: M. Lewis, UC Riverside
When leaves are first forming they are very attractive to psyllids. This is the best time to check for psyllids, and apply foliar insecticides.
When leaves are first forming they are very attractive to psyllids. This is the best time to check for psyllids, and apply foliar insecticides.

Type of treatment Pesticide Name

Effectiveness against ACP 

Duration of control

Application timing
Professional treatment Tempo & Merit High Months

Foliar: when psyllids are present on flush

Systemic: summer or fall
Homeowner-applied broad-spectrum foliar insecticides Sevin, Malathion Moderate Weeks  When psyllids are observed
Homeowner-applied systemic insecticides Bayer Advanced Fruit, Citrus & Vegetable or Monterey Fruit, Tree & Vegetable Moderate Months When psyllids are observed in summer or fall
Homeowner-applied soft insecticides Insecticidal soaps, oils and pyrethrins Low to moderate Days Every 7-10 days during *leaf flushing
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