A successful first year improves pest exclusion at the California state level

IN BRIEF:
    • Invasive pests are a major concern in California. They harm crops, our natural areas, and public health.
    • McRoberts and McGuire are managing a research grants program to help improve the detection of invasive and potentially invasive pests.
    • Research and extension are ongoing for these invasive pests: spotted lanternfly, pink hibiscus mealybug, curly top disease, and Asian citrus psyllid.

A successful first year improves pest exclusion at the California state level

Invasive pests are a major concern in California. Historically, people have brought plants and animals with them from their native lands to California, either accidentally or intentionally. Some introductions resulted in unexpected damage while others had positive outcomes (food and horticultural crops). Many invasive plant problems began as ornamental plants for sale by nurseries and garden centers. Other invasive species arrive in products brought into California by travelers or shipped in commercial trade.

Invasive pests harm crops grown for food and fiber. Aquatic weeds clog waterways and cause substantial changes to California’s wildlands. Insect-carried diseases threaten public health and also affect domesticated and wild animals.

Securing a contract with California Department of Food and Agriculture (CDFA), UC Davis Plant Pathology Professor Neil McRoberts and Project Coordinator Brianna McGuire are managing a research grants program to help improve the detection of invasive and potentially invasive pests. Several projects have successfully completed their first year of work.

Invasive pests harm crops grown for food and fiber. Aquatic weeds clog waterways and cause substantial changes to California’s wildlands. Insect-carried diseases threaten public health and also affect domesticated and wild animals.

Spotted lanternfly

Researchers from Temple University are assessing suitable spotted lanternfly habitat and host plants in California and developing risk-based maps and models to forecast the establishment of spotted lanternfly. The maps and models will also be used as part of a pathway analysis to determine the highest risk points of entry into California by spotted lanternfly from out of state.

Researchers from Penn State are looking at host plant preferences, feeding damage, and survivability of spotted lanternfly on important California crops such as almond, avocado, citrus, fig, grape, hops, kiwi, olive, peach, and raspberry. The research will help elucidate the potential risk of harm to these crops in California in case spotted lanternfly becomes established here.

Master Gardeners as early detectors of invasive pests

Researchers from the University of California are training UC Master Gardener volunteers to be early detectors of spotted lanternfly and pink hibiscus mealybug. Online courses will be created on the identification and biology of the spotted lanternfly, how to scout for and report invasive pests, and the identification and biology of the pink hibiscus mealybug. A reporting tool will be identified for volunteers to use when scouting to report any finds. Evaluation of the online courses and volunteer scouting efforts will inform future training and similar efforts in other locations and with other invasive pests. 

Curly top disease

Researchers from the University of California are validating the use of a loop-mediated amplification (LAMP) assay to detect beet curly top virus in plants and the insect vector, beet leafhopper. Initial work expanded the detection of the LAMP assay for a new beet curly top virus strain that was found in California processing tomato in 2021. Testing changes to the assay components have reduced the levels of false positives. In addition to improving the assay procedures, researchers are assisting growers to identify infected plants in their fields.

Asian citrus psyllid

Researchers from the University of California are assessing the use of two pesticides to manage Asian citrus psyllid on citrus trees in yards. In addition to testing if these pesticides kill Asian citrus psyllid, they are testing how long the pesticide residue remains toxic to the pest and when is the best time to make a pesticide application, Spring or Summer/Fall. This research will provide more tools to protect citrus trees in urban areas from Asian citrus psyllid and the disease it vectors, Huanglongbing.

The five projects funded by California Department of Food and Agriculture will continue for several more years. It is anticipated that the results from these projects will aid Californians in their ability to prevent invasive pests from harming crops and plants grown at home.

Learn more about spotted lanternfly

Learn more about pink hibiscus mealybug

Learn more about curly top in processing tomato

Learn more about Asian citrus psyllid and Huanglongbing

Long-Term Impacts

  • Increased agriculture and forestry efficiency and profitability: Promoting economic prosperity in California
  • Increased ecological sustainability of agriculture, landscapes, and forestry: Protecting California’s natural resources
 

 

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The spotted lanternfly is not in California but would become a major pest in agricultural crops grown here if it became established. Credit: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org. Licensed under a Creative Commons Attribution 3.0 License.
The spotted lanternfly is not in California but would become a major pest in agricultural crops grown here if it became established. Credit: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org. Licensed under a Creative Commons Attribution 3.0 License.
Cottony masses of pink hibiscus mealybug eggs on a silver oak branch. Credit: Jack Kelly Clark, UC IPM. Copyright 2000 Regents of the University of California.
Cottony masses of pink hibiscus mealybug eggs on a silver oak branch. Credit: Jack Kelly Clark, UC IPM. Copyright 2000 Regents of the University of California.
Tomato fruit with curly top disease ripen prematurely. Curly top’s pathogen is carried and moved from plant to plant by the insect, beet leafhopper. Credit: Jack Kelly Clark, UC IPM. Copyright 1987 Regents of the University of California.
Tomato fruit with curly top disease ripen prematurely. Curly top’s pathogen is carried and moved from plant to plant by the insect, beet leafhopper. Credit: Jack Kelly Clark, UC IPM. Copyright 1987 Regents of the University of California.
Asian citrus psyllid feeds and damages new leaves on citrus and ornamental plants in the Rutaceae family. In addition to this damage, Asian citrus psyllid vectors the pathogen that causes Huanglongbing. Citrus trees with Huanglongbing have yellow leaves and bitter fruit. Credit: Mike Lewis, UC Riverside Center for Invasive Species Research.
Asian citrus psyllid feeds and damages new leaves on citrus and ornamental plants in the Rutaceae family. In addition to this damage, Asian citrus psyllid vectors the pathogen that causes Huanglongbing. Citrus trees with Huanglongbing have yellow leaves and bitter fruit. Credit: Mike Lewis, UC Riverside Center for Invasive Species Research.
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