University of Kentucky HortMemo

HortMemo - A University of Kentucky Cooperative Extension Service Newsletter for the Kentucky Nursery/Landscape Industry
Current 2017 HortMemo below

by Winston C. Dunwell, Professor - Nursery Crops Development Center

UK Department of Horticulture

To subscribe send an e-mail to cforsyth@uky.edu or call Christi, 270.365.7541 x 221.

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June 29, 2018



A rough year it turns out. The coldest temperature for us in Princeton, KY was -1.3°F on January 2, 2018 temperatures. While it was -45°F on New Year’s Eve in Embarrass, Minnesota, it was not really cold enough in Princeton, KY to cause extensive injury. Every indication was that the injury was late season often with the evidence of small newly emerging leaves burned off and the distortion mimicking a growth regulator herbicide typical of chilling injury.  We no longer have to worry about the Eucalyptus neglecta level of hardiness 12 plants died even the one that had been evergreen for several years. The Eucalyptus will be removed from further evaluation. The bark splitting on vigorous trees seemed to be related to the subtle differences in environment. We suffered serious damage to ‘Alley Cat’ Pomegranate (even in the over wintering house) and Viburnum luzonicum with them growing out from the ground.  We had some damage on small Crapemyrtles but little to none on our Japanese Maples.  Now we have the rain leading to a close watch for leaf diseases and difficulty keeping pesticides on for Japanese Beetle.

As part of the continuing study of bark beetles, in particular the Ambrosia beetle, by Drs Zenaida Viloria, Raul Villanueva, Win Dunwell and Ric Bessin it has been noted ambrosia beetles population was relatively low but damage appeared in most nurseries in spring 2018.  We have learned ambrosia beetle start traveling by flying close to the ground in February.  The traps need to be set early in February.  Sprays need to go on as a preventative trunk application (see Complete Southeastern US Pest Control Guide for chemical recommendations;  https://content.ces.ncsu.edu/southeastern-us-pest-control-guide-for-nursery-crops-and-landscape-plantings/complete-southeastern-us-pest-control-guide ) Continuous trapping indicates there are some beetles around at almost all times with occasional jumps in the population. Research has pointed to stress on trees as a cause of ethylene release that tells the beetles this is a weak tree prepped for attack. Following Best Management Practices (http://contents.sna.org/) and while doing everything in one’s power to maintain healthy trees is a given for maximum growth and return with ambrosia beetles it impacts the cost of pest damage and control.  The damage has included orchard trees leading to traps in orchards being added to those in nurseries.

A recent search for a local arborist lead me to the Find an Arborist page of the International Society of Arborists. It tells which are members of ISA and if they have and what their ISA certification is.  In that ISA is truly international you can find a certified arborist for anywhere in the world. Check it out at http://www.treesaregood.org/findanarborist/findanarborist


Posters may be presented at the Eastern Region International Plant Propagator’s (ERIPPS) Conference and tours. The IPPS Eastern Region’s 2018 Conference will be from September 23-26 in Newark, Delaware. The Eastern Region Poster Session showcases plant production research as well as practical or new propagation or production ideas. Consider preparing a poster on cool things you do in your company or school; some new production or propagation technique or a new piece of equipment. ERIPPS has a step by step guide to help you through the process: http://admin.ipps.org/uploads/PosterRegForm18.pdf . ERIPPS will even print the poster for you and get it to the conference – doesn’t get easier than that! Check out details on the poster registration form HERE. We need to hear from you by September 1st so that we have a poster backing waiting for you in Newark. Questions? Contact IPPS-ER Poster Chair Win Dunwell (Tel: 270.963.1638; Fax: 270.365.2887 attn Win or by e-mail wdunwell@uky.edu )

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March 14, 2018



Ball Publishing just launched another GrowerTalks newsletter which is focused on pest issues called “Pest Talks,” written by Dr. Juang-Horng “JC” Chong, associate professor of Entomology at Clemson University. JC is a member of the Southern Nursery Integrated Pest Management (SNIPM) group and is an author of all SNIPM Publications including the recent The 2017 Southeastern US Pest Control Guide for Nursery Crops and Landscape Plantings https://content.ces.ncsu.edu/southeastern-us-pest-control-guide-for-nursery-crops-and-landscape-plantings This newsletter will focus on grower tips, tricks, news and research related to pest management techniques. You can sign up to receive his newsletter here

The 2018 IPPS Eastern Region Preconference Tour will depart from our host hotel in Newark, Delaware bright and early on Sunday, September 23rd heading southwest into Maryland for stops at four outstanding operations: The Perennial Farm, http://www.perennialfarm.com/ Manor View Farm, http://www.manorview.com, Foxborough Nursery, http://www.foxboroughnursery.com and Emory Knoll Farms, https://www.greenroofplants.com For an overview of the IPPS-ER Tour see http://files.constantcontact.com/e3309f7c001/24c9679a-a7f0-4cbf-bf74-6c8c6e92cbca.pdf

Recently Kentucky Pest News included a graphic that showed the movement of the Emerald Ash Borer (EAB) in Kentucky. https://kentuckypestnews.wordpress.com/2018/03/13/emerald-ash-borers-2018.  Jeff Stringer, Professor and Chair of the Department of Forestry, produced a publication to guide those land owners and tree farmers on management of Ash tree stands in Kentucky. While it may be late for those in north eastern Kentucky those of us in west Kentucky seem to have time to make decisions relative to Ash trees before the population increases to the level to eliminate ash from our forests. See: http://www2.ca.uky.edu/kywoodlandsmagazine/Vol7_No2/Recommendations_for_Ash_pg4-7.pdf

Tammy Carey was named KNLA Executive Director at the January 24-25, 2018 Kentucky Nursery & Landscape Association (KNLA) Spring Training & Showplace.  She brought with her a long list of suggestions for the future of the association.  For the last two years a very strong KNLA board of directors, volunteers one and all, ran the KNLA under the leadership of past President Kim Fritz, with Wes King, Jeff Wallitsch, Brent Grunfeld, Eric Garris, Stephanie Tittle, Michael Mueller, Pat Carey, Cora Martin, Jeff Moore.  They took control of the website, resolved a financial crisis, planned events, added the bus tour, got sponsors for events and in general made everything better.

The Kentucky Nursery & Landscape Association (KNLA) Summer Retreat will be September 13, 2018. It will be at the very cool CityPlace, LaGrange, KY. For more information contact, KNLA Executive Director, Tammy Carey, e-mail, knla.org@gmail.com and/or keep a watch on the KNLA website  http://knla.org

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January 3, 2018



See you at SNA Researcher’s Conference, MANTS and KNLA Spring Training


Tennessee Boxwood and Sweetbox quarantine; a report from Senior Nursery Inspector, Joe Collins.
At the request of the production nurseries of Tennessee, the Tennessee Department of Agriculture has implemented a boxwood blight quarantine that will become effective February 4, 2018. This WILL impact any KY nurseries that ship (Buxus spp.) boxwoods and/or (Sarcococca spp.) sweetbox to TN.

There are several steps that KY nurseries will need to take before they can resume shipments to TN. First, they will need to become enrolled in a boxwood blight cleanliness program which will be administered through the State Entomologist’s Office. This program is aimed at prevention of the disease and is based upon 6 key steps: exclusion, water management, sanitation, inspection, training and recordkeeping. More information about the cleanliness program can be found at http://www.uky.edu/Ag/NurseryInspection/pdf/boxwood blight cleanliness program.pdf The next step is that each load of boxwoods going to TN will require a state phytosanitary certificate which is issued by the State Entomologist’s Office. Currently there is no charge for these certificates. Lastly, nurseries that ship boxwoods to TN will be required to notify TN Dept. of Ag three days prior to the estimated shipment of the plants.
This quarantine applies to all boxwood and sweetbox (container, B&B, liners, plugs etc). KY nurseries that ship boxwood and sweetbox to TN should contact Joe Collins (joe.collins@uky.edu or 859.218.3341) for more information. It is important to not wait until the last minute to finalize all the details. The boxwood blight cleanliness program may require a site visit by an inspector prior to enrolling in the program and state phytosanitary certificates may require several days to generate.
To see Tennessee Information go to https://www.tn.gov/agriculture/businesses/ag-businesses-plants/plant-pests--diseases-and-quarantines/boxwood.html


February is time to set out your Ambrosia Beetle Traps! While it is cold is a good time to service or build your traps. See Dr. Zenaida Viloria’s trap building article.
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