Western Plant Diagnostic Network1

First Detector News A Quarterly Pest Update for WPDN First Detectors Winter 2015 edition, volume 8, number 1

In this Issue Page 1: Editor’s Note Dear First Detectors, Where do insects go for the winter? Miami? Actually some insects move south for the winter, Pages 2 - 3: Insects in winter such as the famous migration of monarch butterflies to Pages 4 – 5: Mexico and dragon flies to warmer areas. An interview with tentaculata found in CA a specialist in insects at low temperature, Dr. Brent Sinclair, answers this question in the lead article. Two plant Pages 6 - 8: Swede Midge pathologists at the California Department of Food and Agriculture, Drs. Cheryl Blomquist and Suzanne Rooney- Page 8: NPDN online Latham, have identified a new nursery-associated Phytophthora species, P. tentaculata. A new invasive insect Pages 9 - 10: Pale cyst in Canada and the NE US, the swede midge, is a very small nematode spreads in ID and persistent pest of all Brassica crops. Cornell University Page 10: Red palm weevil has assembled a team to study the biology and control of eradicated in CA this midge: Cornell University SWEDE MIDGE Information Center for the U.S. Learn about it so you will be able to

Contact us at the WPDN Regional identify the symptoms if the swede midge keeps migrating Center at UC Davis: westwards. Finally, in Pest Updates there is some bad news Phone: 530 754 2255 and some good news. Email: [email protected] Web: https://wpdn.org Editor: Richard W. Hoenisch @Copyright Regents of the Please find the NPDN family of newsletters at: University of California All Rights Reserved Newsletters

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Photo courtesy of Flickr of courtesy Photo Altizer Sonia by Photo Photo courtesy of Flickr of courtesy Photo

Monarch butterflies migrating A wooly bear caterpillar Goldenrod gall flies Where do insects go in the winter? From an interview with Brent Sinclair, Ph.D., Western University, London, Ontario, by Business Insider When temperatures drop, icicles form, and parkas come out of storage, the bugs seem to vanish completely from the chilliest corners of the world — until months later, like some kind of magic trick... they reappear, as if they'd been there all along. One reason most people are mystified by the fate of insects in the winter is because there is not a simple answer. Some survive as eggs, larvae, or pupae, while others make it through the winter as fully-grown adults.

1. Avoid the cold The first strategy is perhaps the most straightforward. Many insects survive the cold winters by simply avoiding them, employing what Sinclair dubs "the snowbird approach. “ Some, like butterflies and dragonflies, migrate much like songbirds do, heading south en masse as soon as the cold sets in. (Researchers have actually attached tiny radio transmitters to dragonflies to track these

migration patterns.) North American monarch butterflies, the most famous migrating insects, make a long and somewhat miraculous journey to central Mexico each winter. (Swallowtail butterflies do no such thing, sticking out the winter safely encased as a chrysalis instead.) For other insects, avoiding sub-zero temperatures means a journey of inches, not miles. Many aquatic insects wait out the winter at the bottoms of ponds, where they can remain relatively comfortable even when the surface freezes.

Others do the same in the soil, burrowing deep below the frost. Different types of mosquitoes have different winter survival strategies, but some are able to survive cold temperatures by hiding out in sheltered places like "inside the envelope of a house or under a bridge," where they lay in wait in a state called "quiescence." Their next meal won't come till springtime. 2. Carry on as usual While insects seem scarce when December rolls around, some — a rare and hardy

few — continue doing their thing, just like those headstrong outdoorsmen who go camping in the dead of winter. "If you were to put a little trap underneath the snow, you would find some small primitive insects," Sinclair tells us. Some crawl within warm pockets carved out by grass and leaves, while others survive on the surface. 3. Freeze! It's called diapause a dormant, semi-frozen state some insects enter until they thaw out in the spring and crawl off as if nothing had happened. (Despite our fantasies of full-body cryogenics, humans definitely can't do that yet — though some mosquitoes pull off something a lot like it.) The emerald ash borer , a tree-killing invasive species in North America, enters diapause in the winter, which (unfortunately for the northern regions it's infested) means it can survive freezing temperatures. In this state of suspended animation, "they don’t do anything," Sinclair says, "They don’t develop. They just sit under the bark of trees where they’ve been feeding all summer."

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The environmentally damaging creatures are able to stay unfrozen and alive in the cold because a high concentration of their blood is made up of something called glycerol , which acts as an antifreeze. Woolly bear caterpillars, meanwhile, actually freeze into tiny statues but still live through the winter. "Ice forms inside their bodies — you tap them and they’re solid," Sinclair explains. "It's an amazing trick." They can

survive, Sinclair has found in his lab, at temperatures well below anything found on Earth. A lot of body processes shut down so they aren't injured in the meantime. (Goldenrod gall flies perform a similar stunt.)

4. The undead invasion Many insects actually do die in the winter, leaving nothing but eggs behind. That means they are replaced by an entirely new generation in the spring. "You know the crickets that you hear singing in the fall? Those adults that are singing are all going to die in the winter," Sinclair explains. "They lay eggs in the soil, and those hatch in the spring." One problem with our warming winters — yes, parts of

the US are experiencing a cold snap, but nationally it's one of the warmest winters ever recorded — is that insects that are supposed to die off don't, and those that normally can't survive in the coldest areas are moving in and setting up shop. "If you have more and more warm winters, you can get invasive species moving further up and into cold areas," Sinclair says. And all that's stopping non-invasive species, like the mountain pine beetle, "from eating eastern North America," is the blistering cold of the Rockies —

something we may not be able to rely on for long. "Elevated temperatures at high elevations across western North America have allowed mountain pine beetle populations to develop in a single year in areas where two or more years were previously required," noted a report from the US Forest Service.

Photo courtesy of Growing with Science

PhotoDean by Photo by

RobertGorman

Stables

A praying mantis egg case 1.

1. Ladybugs overwintering Photo from Anise swallowtail in a seed pod chrysalis

the A complimentary article to the Dr. Sinclair’s is

MinitabBlog Insect Winter Ecology. His full interview with Business Insider can be found at: What

happens to insects in winter?

Caddisfly larva with portable case of rock fragments

Dr. Brent Sinclair is an associate professor in Western Plant Diagnostic Network News the Department of Biology at Western University in London, Ontario. His research focus is “Insects at Low Temperatures.”

New Species of Phytophthora found in California 4 Phytophthora tentaculata, Kröber & Marwitz (1993)

Twenty years ago, scores of trees began visibly dying off around the San Francisco Bay Area, in what turned out to be the advent of Sudden Oak Death. The cause was a microscopic parasite, Phytophthora ramorum . Phytophthora comes from Greek and means “plant destroyer.” Whereas fungal cell walls are made primarily of chitin, Phytophthora cell walls are constructed mostly of cellulose. Of its many relatives, perhaps the best known is Phytophthora infestans , noted for causing the Irish Potato Famine. It is a genus of plant-damaging (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. An extensive USDA study on the many species of pathogenic Phytophthora species can be found at Emergency Manual of Phytophthora species. As you page down in the document, there are excellent photos and descriptions of the many plant pathogenic Phytophthora species, including P. tentaculata. The species name, tentaculata (tentacle like), perhaps comes from the spider-like mycelium when grown in culture (1).

Phytophthora tentaculata has been detected in several California native plant nurseries and restoration sites. These are the first detections of P. tentaculata in the U.S. It was known previously in China, Germany, Italy, the Netherlands, and Spain. It was first isolated in 1993 in a nursery in Germany infecting , , and Delphinium ajacis. P. tentaculata was initially noticed in a native plant nursery causing a severe root and crown rot in sticky monkey flower, Diplacus aurantiacus subsp. aurantiacus (family Scrophulariaceae ) in Monterey County, CA, in October 2012. Nearly all the M. aurantiacus plants grown in a nursery for a restoration project were stunted and had dull, yellowish leaves. Roots and stem collars had necrotic, sunken lesions with few feeder roots. Thirty percent of the plants had died. Since then it has been detected in four additional nurseries in three counties in CA in addition to three restoration sites where out planted stock was found to be infected. Other plant species known to be susceptible are, Chrysanthemum spp., rocket larkspur (Delphinium ajacis), African daisy ( ), oregano, Verbena, and lavender cotton (Santolina chamaecyparissus ). The California Department of Food and Agriculture (CDFA) just issued a pest alert: CDFA Pest Alert Phytophthora tentaculata . The presence of P. tentaculata in California nurseries could have serious economic impacts on the nursery industry and environmental impacts on susceptible native hosts, if spread into the wildlands. Please see the First Report of this disease by CDFA plant pathologists, Drs. Suzanne Rooney- Latham and Cheryl Blomquist, in the journal Plant Disease.

Photo by David Chesluk by David Photo Dr. Suzanne Rooney-Latham Dr. Cheryl Blomquist

Sticky monkey flower, Diplacus aurantiacus subsp. aurantiacus See the article about P. tentaculata: Tiny Parasite Threatens Native Plants Western Plant Diagnostic Network News by Daniel Potter of KQED

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Zoospores

Sporangia

Chlamydospore

A Generic life cycle of a typical plant pathogenic Phytophthora (Click on the links for the phases of the life cycle)

Latham - 1.

by Suzanne Rooney Suzanne by 2.

Photos Photos

Nursery grown sticky monkey flower Phythophthora tentaculata chlamydospore (1) and plants. Right: healthy. Left: Infected sporangium (2) with Phytophthora tentaculata. Western Plant Diagnostic Network News

Swede Midge, an invasive pest of Brassicaceae 6 Contarinia nasturtii Kieffer, 1888

(order: Diptera , family: Cecidomyiidae), 1. Schrameyer K. by Photo

Swede midge, Contarinia nasturtii , is an invasive insect pest in the Northeastern US that can cause devastating losses to Brassica crops (up to 100%). The name “swede” is a synonym for a rutabaga. It is a small fly, the larvae of which infest brassica plants, causing twisting and distortion of the leaf stems and foliage including death of the growing point in seedlings, or damage to developing flower heads. It is native to Europe and Turkey, and has been introduced into North America where it is regarded as an invasive species. Given the staggering losses caused by the midge and its recent rise in damage in the Northeastern US, there is serious need to develop sustainable pest management strategies prior to the onset of major economic losses. Brassicas are a vital crop for Northeastern vegetable growers; New York is the top producer for fresh cabbage nationwide, and 2nd in processing cabbage (total value of $62 million per year). The current major pest management recommendation, aside from long and widely-spaced rotations, is to use systemic neonicotinoids at planting, followed by weekly applications of neonicotinoids. Alternatives to chemicals pesticides have not been developed. The long-term goals of this project are to develop plant and systems-based pest control options to reduce swede midge infestation. It is a common insect pest in Europe, is a newly invasive pest in North America that constitutes a major threat to cruciferous vegetable and field crops. Since its first identification in Ontario, Canada, in 2000, it has rapidly spread to 65 counties in the provinces of Ontario and Québec and has recently been found in canola (one of two cultivars of rapeseed, Brassica napus L. and Brassica campestris L.) in the central Prairie region where the majority of Canada's 6.5 million ha (16 million acres) of canola is grown. The first detection of Swede midge in the United States was in 2004 in New York on cabbage, then spread to Connecticut, Massachusetts, New Jersey, and Vermont. Since its initial detection in the U.S., swede midge has remained fairly well controlled on conventional farms. It has become a serious threat on small-scale organic farms, and it is for these growers that new research efforts are under way to find this at-risk group management strategies. Grower education is also under way as there are several organic growers who are unaware of SM and do not know how to diagnose it. Host plants for the swede midge include cauliflower, broccoli, cabbage, Brussels sprouts, kohlrabi and a number of wild plants in the brassica family including shepherd’s purse, field penny-cress, field peppergrass and yellow rocket. When a seedling or young plant is attacked, the larvae conglomerate and secrete saliva which softens the plant cuticle and epidermis, sucking in the resulting fluid. On a leaf stalk, this damages the tissues and results in the formation of a corky gall. The undamaged side of the stalk continues to grow normally which results in twisting and distortion. The growing point can be completely killed and secondary bacterial infections can occur. If the infection occurs in the flowering stage of cauliflower, it causes a stunted, multi-branched, tuft- like appearance of the flower-head. See the NPDN Power Point presentation about the swede midge.

Swede midge adults are a small, light-brown fly,

about 1.5-2 mm long. It has very hairy wings. The females’ ovipositor is long, retractile, and needle-

shaped. The adult male will be most frequently AdultMale

Adult Female collected in traps. The antennae of swede midge males are fairly distinctive consisting of 24 antennal segments with beadlike ‘nodes’ separated by more slender, stem-like connections.

www.forestryimages.org www.forestryimages.org Photos: Susan Ellis,Susan Photos:

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PhotoM. by The larvae’s salivary secretions cause the plant to twist and deform, leading to swollen flower buds, crinkled

heart leaves, and swollen, distorted and twisted shoots

Chen and leaf stalks. Note the larvae present on the brassicas below.

PhotoHannah by Fraser,OMAF

Hannah Fraser Hannah

forU.S. the

enter

Photo by by Photo

Severe infestation on broccoli

On red cabbage

SWEDE MIDGE Information C MIDGE SWEDE Information

Photo by Schrameyer K. Photo

Eggs, approx. 0.3 mm long Cabbage with meristem destroyed “blind

heads.”

Maps by Christine by Maps Hoepting al. et

All images are courtesy of the Cornell University imagesare All Cornell the of courtesy

Mapping the spread of the swede midge in North America. Note the jump into Saskatchewan. Western Plant Diagnostic Network News

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Photo by M. Chan by Photo

A swede midge pupa

An excellent site for a very thorough understanding of this insect is: Cornell University SWEDE MIDGE Information Center for the U.S. Cornell has also produced a Swede Midge pest alert.

NPDN on the Internet

The National Plant Diagnostic Network has a YouTube page at: https://www.youtube.com/user/npdnchannel. Many topics are discussed on this channel, such as First Detector Scouting and Reporting Apps, Asian Longhorned Beetle, Photography for Diagnosis, Sudden Oak Death, and several microscopy methods for identification and slide making methods.

Find us on Facebook at the Training and Education Page, a perfect site for First Detectors!

Western Plant Diagnostic Network News

9 Pest Updates

Pale Cyst Nematode (Globodera pallida) spreads in Idaho

The pale cyst nematode (PCN), Globodera pallida , is a major pest of potato crops in cool-temperate areas. It primarily affects plants within the potato family including tomatoes, eggplants, and some weeds. If left uncontrolled, pale cyst nematodes can cause up to 80 percent yield loss in potato fields.

PCN is widely distributed in many potato-growing regions throughout the world. In North America, besides the current find in Idaho, the nematode is also known to be present on the island of Newfoundland, Canada. PCN infestations may be associated with patches of poor growth in potato fields. At high nematode populations, affected potato plants may exhibit yellowing, wilting or death of foliage - none of which has been observed in Idaho potato fields.

Early detection of pests minimizes agricultural production costs and enhances product quality and marketability. Lengthy crop rotation and nematicides (fumigants or granular systemic compounds) are an effective and practical means of control. The current recommendations for rotations are 7 to 15 years without potatoes or host crops. The integration of these methods can be used to manage the nematode population levels below economic thresholds. The Summer 2012 newsletter, pages 7- 8, describes the spread of the nematode. PCN was first found in Idaho in April 2006. In June 2012, two fields, located in Bingham County, total 151 acres and are in close proximity to previously identified infested fields. All 17 confirmed infested fields, 1,916 acres total, are within a 5-mile radius spanning part of southern Bonneville and northern Bingham Counties. Then in December 29, 2014, the Animal and Plant Health Inspection Service (APHIS) added 994 acres to the PCN regulated area in Bingham County, Idaho. APHIS took this action based on the confirmations of PCN cysts in soil samples from four potato production fields in Bingham County between October 28 and December 8, 2014. This action brings the number of PCN-infested fields to 26 and the infested area to 2,897 acres. The total area in Idaho under regulation is 7,734 acres. The cysts were found in soil samples during routine delimiting surveys and ongoing cooperative monitoring efforts by APHIS and the Idaho State Department of Agriculture. All infested fields are within a 7.5-mile radius that spans a portion of northern Bingham County and southern Bonneville

County. For more information, please visit the USDA APHIS PCN page.

Virginia Tech Virginia

Photo courtesy of the Victoria Government courtesy Victoria the of Photo Photo by Jonathan Eisenback, D. by Jonathan Photo Pale cyst nematode on a potato root PCN cyst crushed open to reveal hundreds of eggs. Inside each Western Plant Diagnostic Network News egg is juvenile nematode ready to hatch

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Photo by Christopher Hogger, Swiss Federal Research Station

Biocyclopedia

mage of courtesy I

Potato plant on right infected with the potato cyst nematode compared to healthy plant on left The life cycle of PCN on potato

Some Good News! Red palm weevil declared eradicated in California PhotoJohn by Kabashima UCCE Effective January 18, 2015, the USDA Animal and Plant Health Inspection Service (APHIS) is declaring eradication of red palm weevil (RPW) from the Laguna Beach area of Orange County, California.

On October 15, 2010, APHIS confirmed the first U.S. detection of this pest in a Canary Island date palm tree stump in a residential area of

Laguna Beach, California. A local arborist reported the find, which was determined to be a dead adult RPW. APHIS, Orange County, and the California Department of Food and Agriculture (CDFA) initiated delimitation and visual surveys around the detection site and conducted Red Palm Weevil at Laguna targeted surveys in nearby nurseries. APHIS worked closely with CDFA, Beach CA Orange County, University of California Cooperative Extension, homeowners, local community officials, and arborists to remove several damaged palms and expand the surveys to nearby areas. APHIS PhotoAlfred by Baldacchino provided technical expertise and coordinated outreach and support for the local community to eliminate this pest.

In accordance with European and Mediterranean Plant Protection Organization international standards, a three-year period free from any RPW detections is necessary to declare this area free from this pest.

APHIS has met this standard as the last confirmed detection of RPW occurred on January 18, 2012.

Western Plant Diagnostic Network News

Phoenix palm killed by RPW