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SPRING 2020 NEWSLETTER M i c h i g a n D e p a r t m e n t o f A g r i c u l t u r e a n d R u r a l D e v e l o p m e n t

P l a n t H e a l t h S e c t i o n

In this edition

Box Tree Moth Boxwood Blight in Michigan Sudden Oak Death Spotted Lanternfly Aquatic Plant Sales Industrial Hemp Ag Pilot Program Plant Health Section Contacts

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Box Tree Moth (Cydalima perspectalis) Mike Bryan, Export and Compliance Program Specialist

A new invasive species is threatening boxwood, a popular landscape plant. In 2018, Box Tree Moth (BTM) was detected for the first time in North America in Toronto, Canada. This pest can cause complete defoliation of Buxus spp., leading to death of the plant. BTM has multiple generations per year which increases the potential for damage. The species can survive temperatures as low as -30 degrees C (-22 degrees F).

Figure 1 Common color variant Ferenc Lakatos University of Sopron, Bugwood.org

Figure 1 BTM larvae Ferenc Lakatos University of Sopron, Bugwood.org

Figure 3 Less common color variant Szabolcs Sáfián University of West Hungary, Bugwood.org

Biology Adult female moths lay their eggs in clusters on branches and the underside of leaves of Buxus microphylla and B. sempervirens, including several varietal forms of both species. Larvae are greenish yellow with a noticeable pattern of thin black and white stripes that run along the length of their body (Figure 1). Mature larvae spin a cocoon of white silk among the leaves and twigs of the host plant, where they pass through the pupal stage. Adult BTM have a wingspan of about 4 cm (1.5 inches). There are two color variants: the more common, white variant has white wings with a dark brown border (Figure 2) and the rarer, melanic variant has brown wings with a white streak on the forewing (Figure 3).

Pest Distribution BTM is native to Asia and has spread throughout Europe. Since its detection in Toronto in 2018, BTM has not been found elsewhere in Canada or in the United States.

Pathways of Introduction and Spread In a 2015 New Pest Advisory Group report on BTM, the USDA determined movement of boxwood from infested areas is the most likely pathway of introduction of this pest. The report also noted this species had been encountered at a U.S. port on a single shipment of auto parts from China, indicating this species has the potential for hitchhiking on non-host items.

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Symptoms The adult BTM is easily recognizable due to its coloration and wing patterns and the fact that few other moths frequent Buxus species. Larval feeding damage on the host is the most recognizable symptom found, as evidenced by skeletonizing of the leaves or even complete defoliation (Figure 4). Webbing is another symptom of feeding by BTM (Figure 5).

What You Can Do Carefully inspect all new boxwood you purchase. Train staff to be familiar with symptoms of BTM and other problems such as boxwood blight and incorporate inspection for BTM into routine pest monitoring activities. If you find suspicious symptoms on boxwood, contact your MDARD inspector. If you can get good close-up photos, send those to MDARD for a diagnosis.

Boxwood Blight in Michigan Elizabeth Dorman, MDARD Plant Pathologist

The first confirmation of boxwood blight in Michigan was found in July 2018 at a nursery in Oakland County. Later that year, the disease was found in two other unrelated locations within the county: a homeowner’s yard and in holiday wreaths sold at a retail store. In 2019, four other counties (Ottawa, Mecosta, Washtenaw and Wayne) were added to the list of detections within the state. Boxwood blight was first identified in the U.S. in 2011 and is now present in 28 eastern states, three western states, and three Canadian providences.

What can you do? If you grow boxwood, consider enrolling in the nationally recognized Boxwood Blight Cleanliness Program. Boxwood, Pachysandra, and Sweetbox produced by enrolled nurseries are eligible for special certification allowing growers to meet requirements of boxwood blight quarantines in other states and the requirements by customers. Growers who want to participate can contact their MDARD inspector for more information, or contact Mike Bryan, MDARD’s Export and Compliance Specialist, at 517-284-5648 or email.

If you sell boxwood, follow Boxwood Blight Best Management Practices endorsed by AmericanHort, Horticultural Research Institute and the National Plant Board (version 2.0, revised September 2017).

Figure 4 Larval feeding

Ferenc Lakatos University of Sopron, Bugwood.org

Figure 5 Larval feeding

Ferenc Lakatos University of Sopron, Bugwood.org

For additional information, contact your MDARD inspector or contact Mike Bryan, MDARD Plant Health Specialist at 517-284-5648 or email.

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If you suspect you’ve received infected boxwoods or Pachysandra from another nursery, contact your local MDARD inspector to evaluate if a sample is needed. If boxwood blight is confirmed, infected plants and plant debris will need to be removed and destroyed by double-bagging the diseased material and disposing of it in a landfill or by burning it on site.

If you suspect boxwood blight on a customer’s property, send samples to MSU Plant & Pest Diagnostics.

Leaf drop due to boxwood blight in a boxwood hedge is typically on lower branches and where infected plants meet. Photo by Amy Kennedy, MDARD

Characteristic black stem lesions of boxwood blight on boxwood stem. Photo by Amy Kennedy, MDARD

For more information on boxwood blight, visit www.michigan.gov/invasives, click on “Species Profiles & Reporting Information” and then select “Disease”. Information about boxwood blight is near the top of the page.

Additional information from MSU Extension is also available here.

Sudden Oak Death (Phytophthora ramorum) Mike Bryan, MDARD Export and Compliance Program Specialist

Sudden Oak Death is a tree disease caused by the fungus-like plant pathogen Phytophthora ramorum. The pathogen is considered especially dangerous because it affects a wide variety of trees, shrubs (e.g. Rhododendrons and Camellias) and other common horticultural plants, and there is no known cure. The pathogen has killed millions of live oak (Quercus agrifolia), and an oak relative, tanoak (Notholithocarpus densiflorus) in California and Oregon. To date, Phytophthora ramorum has not been established in the Midwest.

Over 100 plant species and cultivars representing more than 70 genera are susceptible to P. ramorum or

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facilitate its spread. Some of the plants important to Michigan’s nursery and landscape industries include Douglas-fir, rhododendron, lilac, oak, pieris, and viburnum.

Phytophthora ramorum is known to spread through infected plants and wind-blown rain, as well as contaminated irrigation water, soil, or gravel substrates. The fungus can also be moved unknowingly in used pots or contaminated potting mix.

Depending on the plant species, P. ramorum infections may have symptoms ranging from leaf spots to twig dieback, but these hosts rarely die from the infection. Other plant pathogens (e.g., native Phytophthora spp.) and environmental stresses can produce similar symptoms and positive diagnosis is possible only via laboratory testing.

Because this pathogen is a federally regulated organism in the United States, detection of infected plants will result in eradication efforts. USDA-APHIS works with other federal agencies, states, conservationists, and the nursery industry to limit the human-assisted spread of P. ramorum in the United States through regulations, survey and public outreach programs. Regulatory measures may include restricting importation, shipments and sales of potential host plants, and eradicating the pathogen by destroying infected and suspicious nursery plants and disinfecting nursery facilities.

Since 2006, MDARD has participated in federally funded surveys for P. ramorum that involve visual inspection and laboratory testing of disease symptoms on susceptible hosts at target sites such as nurseries, garden centers and waterways. All survey samples have been negative for P. ramorum thus far.

In July 2019, USDA-APHIS notified MDARD that shipments of potentially infected plants, originating from nurseries in Washington State and Canada, were delivered to several eastern and midwestern states, including Michigan. MDARD conducted multiple trace-forward investigations including sampling from this event and found that one nursery received plants which tested positive for P. ramorum. The positive plants were destroyed, and samples were collected from host material at the nursery over a 90-day period. All the subsequent samples tested negative for P. ramorum. The nursery will be monitored and inspected for the next two years.

Introduction of P. ramorum to forests has Phytophthora ramorum on a Rhododendron leaf Photo by: Joseph O Brien, USDA Forest Service, potential to destroy native oaks. The

Bugwood.org pathogen poses a serious impact on Michigan’s nursery and landscape industries since it can infect a wide range of ornamental woody plants, and it can spread to nurseries, homes, gardens, parks and natural vegetations via movement of infected plant materials. MDARD will continue to conduct surveys to monitor new introductions of P. ramorum and work with USDA-APHIS to respond to trace-forward investigations involving infected nursery stock originating from the western states.

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The recommended Best Management Practices (BMPs) consist of biosecurity guidelines created to assist nursery crop producers in developing an effective monitoring and action plan to reduce the risks associated with P. ramorum. The control of P. ramorum is based on minimizing the risk of introduction and preventing the establishment of the pathogen within the nursery.

Individual nurseries are encouraged to review the BMPs and voluntarily apply some or all of them, depending upon their production systems, physical location, nursery type, regional climatic conditions, geographical location and the plants they grown.

If you find something suspicious on a susceptible host plant, please contact your local MDARD inspector or contact MDARD at 800-292-3939.

Pest Prevention/Management Training Internal/External Audits Records/Traceability Documentation

Best Management Practices are divided into five management categories:

Spotted Lanternfly Robert Miller, MDARD Invasive Species Prevention and Response Specialist

Spotted lanternfly (SLF) is an invasive planthopper posing a serious threat to the nursery, landscape, fruit, hops, and logging industries. Hosts include apple, cherry, grape, maple, plum, oak, sycamore, and willow.

SLF damages host plants directly by sucking sap, and it damages them indirectly due to mold that grows on its honeydew excretions. Large infestations of SLF stress plants by depriving them of nutrients they need for growth and maintenance, weakening them, and eventually contributing to their death.

SLF is native to eastern Asia. It was detected in Pennsylvania in 2014 and is now found in several neighboring states. Egg masses are difficult to identify and can be transported to new areas on nursery stock, vehicles, and other infested objects.

If you see adults or immature stages, take pictures, record the location, and collect specimens in a rigid container. If you see signs and symptoms, take pictures and note the location. In either case, contact MDARD at 1-800-292-3939.

Adult spotted lanternfly Photo by: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org

Larval spotted lanternfly. Photo by: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org

Adult spotted lanternfly Photo by: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org

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Aquatic Plant Sales Mike Bryan, MDARD Export and Compliance Program Specialist

As of March 21, 2019, anyone selling a live, non-native aquatic species is required to register with the Michigan Department of Natural Resources (DNR). In late 2018, the Michigan Legislature amended the Natural Resources and Environmental Protection Act (Act 451 of 1994, Section 41335) to require all retailers of live, non-native aquatic species to register with MDNR every calendar year. The new law amendment applies to people selling live, non-native aquatic plants in Michigan, as well people selling crayfish, snails, mussels, turtles, amphibians and other aquatic organisms in the state.

Sellers of non-native species can register online at Michigan.gov/SellAquatics. The registrant receives a confirmation number that must be clearly posted at the selling location on a registration certificate.

A downloadable certificate form is available through the a MDNR. Sellers can print and add their registration number

Learn more registration for easier posting. The certificate must be posted at each sales requirements: location. Offsite sales at auctions or tradeshows also require a separate registration and certificate. The online tool DNR news release collects information regarding name, address, business or DNR: Frequently Asked Questions: sale location, and aquatic organism type. The new law Registering to Sell Aquatic Organisms amendment defines “aquatic plant” as a “submergent, MSU Extension article, Registration emergent, obligate wetland, facultative wetland, or floating- now required to sell non native leaf plant or a fragment thereof, including a seed or other aquatic plants propagule.”

According to the MDNR March 11, 2019 news digest, annual registration will give MDNR a clear picture of the types of live aquatic species being sold in Michigan. This will help identify potential invasive species threats that could result from releasing unwanted aquatic organisms available in trade into Michigan's waters.

To learn more about registration requirements, visit the MDNR website or see the MDNR document: Frequently Asked Questions (FAQ): Registering to Sell Aquatic Organisms. The FAQ document identifies exemptions to the requirement such as species that cannot survive in Michigan’s climate. Also see the related MSU Extension article, registration now required to sell non-native aquatic plants.

Aquatic organism sellers should also note that the new amendment requires sellers to submit information each year on quantity of non-native aquatic species sold. Additional information on the reporting process will come from MDNR.

Industrial Hemp AG Pilot Program Gina Alessandri, MDARD Industrial Hemp Program Director

In April 2019, MDARD launched the state’s first industrial hemp program, adding a new crop to the state’s farming community.

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The 2018 U.S. Farm Bill authorized the commercial production and processing of hemp, also known as industrial hemp, in the United States. Hemp is cannabis (Cannabis sativa L.) with less than 0.3% tetrahydrocannabinol (THC), the psychoactive component found in marijuana. Hemp is cultivated to produce fiber, grain, biomass or non-intoxicating, therapeutic compounds such as cannabidiol (CBD).

As one of the nation’s most agriculturally diverse states, Michigan is uniquely positioned to grow, process, and manufacture industrial hemp. This emerging crop not only creates new opportunity for our farming community, but also offers an avenue for new businesses to develop across the state.

The United States Department of Agriculture (USDA) published its Interim Final Rules on the establishment of a domestic hemp program and is seeking public comments before finalizing a national program. In the meantime, MDARD is utilizing authority from the 2014 Farm Bill for an Industrial Hemp Ag Pilot Program and will continue it into 2020.

The USDA Interim Final Rules provide guidance on federal requirements as states across the nation draft state hemp plans for approval. MDARD is currently reviewing the rules to identify needed changes to our state law. Once statue changes are made and approved, MDARD will provide oversight of the commercial hemp program.

Prohibits a person from growing hemp in Michigan unless registered with MDARD as a grower.Requires growers to identify all growing locations on their grower application. Prohibits a person from processing, handling, brokering or marketing hemp unless licensed as aprocessor-handler.Requires signage to be placed at the boundaries of each growing area. Requires growers to have their crops tested for THC content prior to harvest.Requires individuals to show proof of registration and licensing upon request by law enforcement. Pre-empts local units of government from adopting any rule, regulation code or ordinance to restrictor limit any hemp cultivation or processing.

The Michigan Industrial Hemp Research and Development Act of 2018:

While there is excitement around the state’s newest crop, many questions remain on the long-term regulation of hemp, CBD and hemp products. There is a learning curve for everyone involved in this budding commodity – farmers, federal and state regulators and local authorities. The 2019 and 2020 Industrial Hemp Ag Pilot programs have and will continue to provide an opportunity for all to learn.

Michigan’s Public Act 641 of 2018 authorizes the growing and cultivating of hemp and requires the registration and licensing of persons who are interested in growing, processing, and handling hemp.

People growing or processing hemp in the state must have a valid license from MDARD. Licenses to grow or process hemp in Michigan are available at any time. Those interested can download and complete the Hemp Grower Registration Application and the Hemp Processor-Handler Application on Michigan’s Hemp website. The cost for grower registration is $100 and the processer-handler license is $1,350.MDARD is currently issuing licenses for the 2020 Hemp Ag Pilot program as licenses expire annually on November 30.

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Hemp field in Michigan Photo by Gina Alessandri, MDARD PPPM

Hemp field in Michigan Photo by Gina Alessandri, MDARD PPPM

For additional information on Michigan's industrial hemp ag pilot program, visit www.michigan.gov/industrialhemp.

Lansing Office Contacts If your organization would like an inspector to give a talk about invasive forest pests, please contact Robert Miller, MDARD Invasive Species Prevention and Response Specialist, at 517-284-5650 or email.

Please visit our websites: Nursery Licensing and Inspection Quarantine Compliance Invasive Species

Program Area Staff and Position Contact Information

Nursery grower and dealer Andria McCubbin Green, mccubbingreena@michigan.gov licensing and inspection Acting Nursery Specialist 517 599 5748

Nursery license application Lisa Leibrand, leibrandl@michigan.gov processing and issuance Licensing Technician 517 284 5656

Certification to meet other states Mike Bryan, bryanm@michigan.gov requirements § Foreign Export § Export and Compliance 517 284 5648 Quarantine Compliance Specialist

Christmas tree inspection Josh Grant, grantj5@michigan.gov scheduling Plant Health Section Technician 517 284 5651

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Program Area Staff and Position Contact Information

Exotic pest outreach and Rob Miller, millerr35@michigan.gov education § Asian Longhorned Pest Response Specialist 517 284 5650 beetle & hemlock woolly adelgid

Terrestrial species state Susannah Iott, Iotts@michigan.gov management plan Quality of Life Invasive Species 517 420 0473 § Firewood certification

State Plant Regulatory Official Robin Rosenbaum, rosenbaumr@michigan.gov Plant Health Section Manager 517 284 5646

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