- Author: Sandipa Gautam
USDA-APHIS Approves New Fuller Rose Beetle Mitigation – a Voluntary Option to Reduce Pesticide Applications
By
Sandipa Gautam, Area Citrus IPM Advisor UCCE
James R Cranney, President CCQC
At the request of the California Citrus Quality Council (CCQC) USDA's Animal and Plant Health Inspection Service (APHIS) has approved a new sampling protocol that growers can use to reduce pesticide applications for control of Fuller rose beetle (FRB), a quarantine pest in South Korea.
Fuller rose beetles are brown, flightless, snout beetles that have one generation in a year (Figure 1). Three-fourths of their life cycle is spent under the ground where they feed on roots and go through development. Adults emerge from the ground year-round, but the major emergence in the San Joaquin Valley occurs July-September, with 53% of beetles emerging in August. All beetles are females and adult females do not require mating to begin reproduction. Beetles climb to the tree canopy and feed on citrus leaves and lay eggs on cracks and crevices including the under the sepal (Figure 2). Eggs can be present at the time of harvest, thereby making this beetle a quarantine concern for Korea's Animal and Plant Quarantine Agency.
Figure. 1. Fuller rose beetle adult (right there, centered in the triangle).
Figure 2. Fuller rose beetle egg masses, live eggs (A) – note yellowish and plump eggs; dead or hatched eggs (B) – dried out egg mass.
Current Practices for FRB Management
Growers have been using a system's approach which combines cultural and chemical methods to target FRB, since 2010. The goal of FRB management is to reduce the beetle population and egg laying. Current regulatory requirements for managing FRB are
a) Skirt Pruning sufficient to prevent tree skirts from contacting the ground
b) Weed control sufficient to prevent forming a bridge from ground to tree skirt
c) Two insecticide treatments to control Fuller rose beetle using only University of California recommended pesticides from the UCANR IPM Guidelines web page at http://ipm.ucanr.edu/PMG/r107300311.html
In recent years, most growers and pest control advisors have reported that they no longer detect beetles in most citrus groves. Furthermore, the USDA APHIS interception rate from phytosanitary inspections, where 600 fruits per container are sampled for FRB egg masses, FRB was found in only 0.05 percent of all containers. This indicates that FRB populations are very low in citrus groves.
Since FRB populations in citrus groves are historically low, CCQC has proposed an additional voluntary option for the Korea FRB Protocol to reduce pesticide use:
- Trees must be skirt pruned to minimize branches touching the ground.
- Herbicide treatments should be made to eliminate weeds that could be a pathway into the tree.
- Either option a or option b
a) Growers must make two pesticide applications to control FRB using pesticides recommended on the University of California Citrus IPM website https://ipm.ucanr.edu/agriculture/citrus/fuller-rose-beetle/
b) Growers must use the FRB sampling protocol (below), keep records and if no more than two FRB-infested trees per sample are detected they may eliminate the first application and make one application, preferably before October 31 with pesticides recommended on the citrus IPM website.
Fuller Rose Beetle Sampling Protocol:
- Growers should conduct Fuller rose beetle (FRB) sampling from Aug. 7 – Aug. 31 since that is the peak period of emergence.
- Conduct a random sample in each citrus block.
- Divide the block into four quadrants and sample 18 trees that are spread equally apart in each quadrant. A total number of trees sampled is 72 trees.
- Growers or Pest Control Advisors (PCA) should:
i. Check suckers inside the tree for signs of FRB leaf chewing and if beetles are detected the tree is considered infested.
ii. If no beetles are found in the interior, shake two large outside branches over a light cloth and inspect for FRB. If beetles are found, the tree is considered infested.
- Growers must keep records on the results of the sampling including (i) block identification, (ii) inspection date, (iii) name of inspector, and (iv) number of trees infested with beetles out of 72 trees inspected.
- If no more than two infested trees are found, growers may eliminate the first FRB pesticide application. If two infested trees are found, growers must make a pesticide application in August or early September.
- If no more than two infested trees are found, growers are still required to make one pesticide application to control FRB, preferably before October 31.
How will the new protocol help?
- Reduced pesticide use could reduce grower costs to manage FRB.
- Fewer pesticide applications should improve biological control in citrus groves by preserving beneficial insects. Many PCAs and growers attribute severe mealy bug outbreaks to increased pesticide use to control FRB and Asian citrus psyllid.
- Reducing pesticide use to control FRB will help California citrus growers adopt more sustainable production practices and align the industry with the California Department of Pesticide Regulation's Sustainable Pest Management Roadmap.
References:
UCIPM 2017. Citrus Pest Management Guidelines: Fuller Rose Beetle. https://ipm.ucanr.edu/agriculture/citrus/fuller-rose-beetle/
- Author: Ben Faber
The Argentine ant is the most widespread species of invasive ant, thriving in urban areas, agricultural settings and nature parks on every continent except Antarctica. The species can form "supercolonies" that link hundreds of nests and millions of workers. While Argentine ants do not bite or sting humans, they can be a nuisance in buildings and cause economic and ecological damage to agricultural businesses and natural areas where they outcompete native ant species.
In orchards and vineyards, the Argentine ant is a stalwart defender of aphids, scale, and mealy bug, which excrete a sweet honeydew that the ants drink. The ants protect the pests from parasites, predators and parasitoids, allowing them to flourish and cause other problems such as sooty black mold, a dark fungus that can block leaves' access to sunlight, scaring fruit and reducing yield. The ant is a major problem in such crops as cherimoya, pitahaya and passion fruit which have few registered chemicals for use commercially. They are the major cause for use of pesticides in coastal lemon orchards.
A new technique for controlling Argentine ants has been developed using hydrogels, allowing for precise control of this pest with little impact on other species. The hydrogels have a sugar solution for attracting the ant and can be laced with a variety of pesticides, both conventional and organically-approved. The baits, though, have a fraction of the normal amounts of pesticides that are registered for foliar or ground applications, reducing pesticide load on the environment and disruption of biological control. And they can be registered on some of these orphan crops like sapote. And in one case, the hydrogels are made of biodegradable algae.
Argentine Ants Feeding on Sugar-infused Hydrogels
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=27502
https://www.universityofcalifornia.edu/news/using-seaweed-kill-californias-least-favorite-ant
- Author: Ben Faber
Avocado Irrigation Workshop
August 10 (Thursday), 2023
1:00 – 4:00 P.M.
San Diego Farm Bureau
420 S Broadway, Escondido, CA 92025
Workshop registration link:
https://surveys.ucanr.edu/survey.cfm?surveynumber=40798
1:00 - 3:30 p.m. Agenda
1:00 Welcome
1:05 Challenges Due to Climate Change and Tools and Resources to Manage Risks - Dr. Tapan
Pathak, CE Specialist in Climate Adaptation in Agriculture, University of California, Merced
1:35 Interpreting Your Water and Soil Analysis Reports to Manage Your Avocado Grove – Dr.
Ben Faber, UCCE Subtropical Crops Advisor, Ventura and Santa Barbara Counties
2:05 Cost-effective Irrigation Tools for Efficient Water Management of California Avocados – Dr.
Ali Montazar, UCCE Irrigation and Water Management Advisor, San Diego, Imperial, and
Riverside Counties
2:35 Considerations about the Use of Plant-Based Sensors for Avocado Irrigation Scheduling –
Dr. Jochen Schenk, Professor of Department of Biological Science, California State University,
Fullerton
3:05 Development and Evaluation of Pathogen and Salinity Resistant Avocado Rootstocks – Dr.
Patricia Manosalva, Professor of Plant Pathology and Microbiology Department, University of
California, Riverside
3:35 RCD of Greater San Diego County Irrigation Management Programs and Projects – Joel
Kramer, Resource Conservation District of Greater San Diego County, Lakeside
4:00 ADJOURN
For more information about the workshop, please contact Ali Montazar, amontazar@ucanr.edu.
PENDING CEU CREDITS: CCA (3.0 hrs.)
SDRILG (3.0 hrs.)
- Author: Ben Faber
Invasive species are arriving in California with increasing frequency. The best time to stop them is before they arrive, and federal, state and local agencies are keeping their eyes out for new arrivals and threats on the horizon. When they do arrive, Early Detection and Rapid Response is critical to their management. Many detections are made by individuals not associated with any agency or university, and through community/participatory science programs, almost anyone can help to spot the next invasive.
The 2023 Invasive Species Lunchtime Talks all took place via Zoom Webinar from noon to 1:00 p.m. from Monday, June 5 through Friday, June 9. All of the sessions were recorded and can be viewed at https://ucanr.edu/sites/invasivelunch/2023.
- Author: Greg Douhan and Georgios Vidalakis
The California Department of Food and Agriculture (CDFA) regularly performs surveys across the San Joaquin Valley (SJV) to monitor for potential insect and pathogen issues for California agricultural producers. In October of 2021, CDFA inspectors began performing a multi pest survey for citrus in addition to the routine inspections for the Asian citrus psyllid and Huanglongbing in residential properties. In March of 2022, a surveyor came across some unique leaf symptoms on a residential lemon tree in the city of Tulare, CA. Samples from the initial find in Tulare County were sent to CDFA's Plant Pest Diagnostic Center in Sacramento, California (https://www.cdfa.ca.gov/plant/PPD/) and tested positive for the citrus yellow vein clearing virus (CYVCV), a putative new member of the genus Mandarivirus associated with the yellow vein clearing disease of citrus. This result was subsequently confirmed by the United States Department of Agriculture, Plant Pathogen Confirmatory Diagnostics Laboratory (https://www.aphis.usda.gov/aphis/ourfocus/planthealth/ppq-program-overview/science-technology/plant-pathogen-confirmatory-diagnostics-laboratory).
After consulting with the United States Department of Agriculture regarding sampling strategies, delimitation surveys are continuing to determine the extent and distribution of CYVCV in California. Once a positive tree has been identified, CDFA returns to the property and surveys all citrus trees within a 1-mile delimitation radius around the detection, additionally CDFA conducts delimitation surveys in arcs around the delimitation core. Around the initial detection core in the city of Tulare, CDFA has already conducted 7-mile and 6-mile arcs and around the new core CDFA is conducting a 4-mile arc delimitation survey. All samples are sent to CDFA's Plant Pest Diagnostic Center for molecular testing. A total of 578 trees have tested positive so far for CYVCV in the city of Tulare and recently two trees tested positive in the city of Visalia, but no findings in commercial citrus groves in the SJV have been reported thus far.
Symptoms of CYVCV disease include vein clearing when viewed from the top of the leaves and water soaking when viewed from the bottom of the leaves. Symptomatic leaves may also be curly or have some crinkling. Researchers from other parts of the world have reported that the virus is vectored by the citrus white fly (Dialeurodes citris) and several aphid species (Aphis spiraecola, A. craccivora, and A. gossypii.), all of which occur in California. Currently scientists are performing experiments to determine vector transmission under California conditions. There have also been single reports of virus detection on some weed species and CYVCV can also spread by grafting techniques as well as by pruning tools.
The disease was first identified in Pakistan in 1988 on lemon and sour orange trees. The virus disease was then found in India on ‘Etrog' citron, ‘Rangpur' lime, sour orange, and lemon trees in India in 2003. The disease was subsequently found in Turkey, Iran, and China. Lemons and sour orange seem to be the most susceptible types to this disease, but most citrus species, varieties, and hybrids tested thus far developed the disease with varying symptomatology. Finally, there has also been one report of CYVCV infecting wild grapes in Turkey in 2020. In the study from Turkey, the infected wild grapevine was climbing on an infected citrus tree. There was no evidence of serious impacts on the wild grapevine.
It is also important to note here that the citrus yellow vein clearing virus (CYVCV) is not related to and should not be confused with the citrus yellow-vein associated virus-like RNA (CYVaV). CYVaV was recently identified to be associated with the citrus yellow-vein disease reported once in California in the 1950s in a few limequat trees, but since then, it has not been reported again in California.
The report of CYVCV from the city of Tulare, California was the first account of this virus in North America, and the impacts of this disease on the citrus economy are not clearly known at this time. Researchers in China have reported up to 80% loss in production in some lemon groves but the losses are usually less in most instances. CDFA continues with delimitation surveys around the positive finds to define the extend of the infestation and if any commercial citrus operations, groves or nurseries, are infected or are at risk. For updates on this and other citrus pests in California visit ‘Citrus Insider' at https://citrusinsider.org/.
