for Arborists, Landscape Managers & Nursery Managers

Commercial Horticulture May 5, 2017Coordinator Weekly IPM Report: Stanton Gill, Extension Specialist, IPM for Nursery, Greenhouse and Managed Landscapes, sgill@umd.edu. 301-596-9413 (office) or 410-868-9400 (cell)

Regular Contributors: Pest and Beneficial Insect Information: Stanton Gill and Paula Shrewsbury (Extension Specialists) and Nancy Harding, Faculty Research AssistantDisease Information: Karen Rane (Plant Pathologist) and David Clement (Extension Specialist)Weed of the Week: Chuck Schuster (Extension Educator, Montgomery County)Cultural Information: Ginny Rosenkranz (Extension Educator, Wicomico/Worcester/Somerset Counties)Fertility Management: Andrew Ristvey (Extension Specialist, Wye Research & Education Center)Design, Layout and Editing: Suzanne Klick (Technician, CMREC)

In This Issue...

If you work for a commercial horticultural business in the area, you can report insect, disease, weed or cultural

plant problems found in the landscape or nursery to

sklick@umd.edu

TPM/IPM Weekly Report

- Ticks- Ambrosia beetle update- Pest Walks- Powdery mildew on bluegrass lawns- Weird weather- Honeylocust spider mite- Lace bugs- Cottony camellia/taxus scale- Rose midge- Crape myrtle aphids- Yucca plant bugs- Hawthorn sawfly leafminer- Maple petiole borer- Biofouling of irrigation systems- Euonymus caterpillar- Predator activity

Beneficial of the WeekPhenologyDegree DaysAnnouncements

Pest Predictive Calendar

IPMnetIntegrated Pest Management for

Commercial Horticulture

extension.umd.edu/ipm

TicksBy: Stanton Gill

In the last IPM Alert, I mentioned that you need to watch out for ticks. I received several e-mails asking about treatment for dogs and cats for ticks. For the last 10 years it seems everyone has been treating their pets with indidacloprid. It is so widely used that resistance by ticks is being detected.

Now, a company called Zoetis Corp has released a new product called Simparica for use on dogs for tick prevention. Simparica is a flavored, chewable tablet to use on dogs older than 6 months old. It is in a family of chemistry called isoxazoline parasiticide. It provides about 30 - 35 days of protect from ticks.

Ambrosia Beetle Update By: Stanton Gill

With the warm weather at the end of April and early May, we continue to see strong flight activity from ambrosia beetles. Samples sent in from a nursery in Central Maryland, a landscape site in Frederick near Ft. Detrick, and a nursery in Carroll County confirms that Xylosandrus germanus and Xylosan-drus crassiusculus are still flying this week. Protectant sprays of bifethrin or permethrin usually provide protection for 30 – 45 days.

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Look for gray to white mycelial growth of powdery mildew disease in bluegrass turf after the recent rainiy weatherPhoto: Joseph Roberts, UMD

Improve Your IPM Diagnostic Skills With Stanton Gill, David Clement, and Karen Rane

There is a lot of activity from insects, mites and diseases in the landscape in May. If you want to hone your diagnostic skills we will be conducting two on-site walk around IPM sessions with pathologists and an entomologist. At the Cylburn Arboretum location we will also have a horticulturist, the famous Phil Normandy, of Brookside Gardens helping with tree identification. There are beautiful specimen trees at the Cylburn arboretum that will help give you ideas for superior trees suited for urban environments.

May 11: The first session is at Salisbury University and will involve a tour of the grounds. Salisbury University has been honored for the past 2 years with the Tree Campus USA award. During the afternoon walk, David Clement and Stanton Gill will be guiding you through the pests of the Eastern Shore. The program starts at noon and ends at 3 p.m. on May 11.

For more information and to register: https://2017ipmpestwalk.eventbrite.com. Registration fee includes lunch. Contact for program: Ginny Rosenkranz, 410-749-6141.

May 23: The second session will be on May 23 at the Cylburn Arboretum in Baltimore, Maryland. This evening session starts at 5:00 p.m. and goes until dark. David Clement, Karen Rane, Phil Normandy, and Stanton Gill will be guiding you through the diagnostic process for landscape disease, plant ID and pest problems.

To register contact the Maryland Arborist Association at http://060412a.membershipsoftware.org/files/2017_Pest%20Walk%20Brochure_WEB%20FINAL.pdf. Registration fee includes dinner.

Powdery Mildew on Bluegrass LawnsBy: Joseph Roberts, University of Maryland Turfgrass Pathologist

With the recent rainfall over the past few weeks, you may have noticed some grayish-white mildew residue on your bluegrass lawn. But while that residue may seem to rub off with your fingers, it is actually a fungus that thrives in cool, humid weather. The powdery mildew fungus, Erysiphe graminis, survives the winter months by living in grass tissue, only to emerge in the spring months producing numerous spores that can blow in the wind and spread the fungus to neighboring plants. Infection is normally observed as gray to white mycelial growth as observed in the photo, but in severe cases, the turf can become yellow and may thin out if conditions remain suitable for extended periods. Kentucky bluegrass is particularly susceptible, especially in heavily shaded conditions. Control: Since powdery mildew is typically observed in shaded areas that are cool and moist, cultural practices that increase airflow, drainage, and sun exposure will aid in reducing symptoms. In areas where the problem is persistent, consider planting shade tolerant turfgrasses, such as tall fescue or fine fescues as these are typically resistant to powdery mildew. Cultural management practices can go a long way to reducing this issue and fungicides are rarely needed.

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Honeylocust spider mites are orange to red; their feeding causes stippling damage on honeylocusts

Honeylocust Spider MiteBy: Stanton Gill

There are many honeylocust trees that have been placed in urban landscapes over the last decade. There is a mite you need to be aware of in early May that attacks the honeylocust trees. Honey locust spider mite, Eotetranychus multidigituli attacks honeylocust, Gleditsia triacanthos. This mite overwinters as adult females. The adult females hide in the crevice of the bark on a branch of honey locust. Eggs are laid in the May. Light feeding can cause white or yellow stippling on the leaves. Heavy feeding can cause honeylocust foliage to turn brown and die. Control: Large overwintering populations could have been treated back in early April with a dormant rate (2-4%) horticultural oil spray. You have to get complete coverage in bark cracks and crevices as possible where these tiny red-colored mites are seen. If populations are low, avoid using other chemical pesticides for management as they may impact populations of beneficial, predatory mites which usually manage honeylocust spider mite effectively. If the population is higher then try using Hexygon or Tetrasan. These are both mite growth regulators and give long control of honeylocust spider mites.

Weird Weather in Central MarylandBy; Stanton Gill

A coworker mentioned that Takoma Park suffered through a meso-cyclone on April 21. The meso-cyclone cut a swath through part of Takoma Park, felling many trees and destroying buildings. We had a similar incidence last summer near CMREC in which trees were felled like toothpicks. Seems we are getting more and more of this isolated violent weather.

A storm on April 21 caused extensive damage to buildings and trees in Takoma ParkPhoto: Sara Tangren, UMD HGIC

Lace BugsWe continue to receive reports of lace bug activity. John Ford, Thrive, Inc., found lace bugs on potted pieris in McLean, VA this week. Look for yellow stippling of new growth. Look on the underside of foliage for nymphs, adults, and black fecal spots. Damage on new growth indicates eggs have hatched and the new generation has started to feed. For control, get good coverage with horticultural oil on the underside of foliage to reduce populations. Many products are labeled for lace bugs.

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Look closely at damaged rose tips for rose midge larvaePhoto: Jessica Frakes, Thrive, Inc.

Cottony camellia/taxus scale can produce a lot of honeydew on which sooty mold grows; note the blackened stemPhoto: Tony Murdock, Fine Pruning

Cottony Camellia/Taxus ScaleCottony camellia/taxus scale females are starting to produce egg sacs. Ron Rubin, Thrive, reported many egg sacs present of this scale on May 3. Tony Murdock, Fine Pruning, found this scale on May 1 in Brunkswick and noted that it is one of the worst infestations that he has seen in a long time. We also recieved a sample of scale on taxus. Oscar Peña, Wray Brothers Landscapes, found egg sacs on holly on May 1. On his samples, there were also many psocids present. Psocids live in moist areas and feed on mildew and mold, including the sooty mold that grows on honeydew produced by the soft scale.Monitoring: Monitor plants closely because the crawler stage will be occuring later this month. Look for yellowing of foliage and plant dieback in severe infestations. This soft scale produces large amounts of honeydew on which sooty mold will grow. There is one generation a year, but each female can produce over 1000 eggs so populations can build up quickly. Control: Wait for eggs to hatch and then treat with pyriproxyfen (Distance) or buprofezin (Talus) mixed with0.5 - 1% horticultural oil.

Psocids were found on a holly sample that had cottony camellia/taxus scale; the psocids feed on the sooty mold growing on the honeydew

Rose Midge Jessica Frakes, Thrive, Inc., found rose midge activity in Bethesda on May 4. Early timing is very important for getting control. Removing mulch around rose shrubs in late winter removes some of the pupating rose midges. Putting fresh mulch on in early spring buries deeper any remaining midges. Physical removal can also help with control. Monitor weekly for infested shoots throughout the growing season and prune off infested shoots when possible. There are multiple larvae in one shoot. Black shoots are an indication that the larvae are gone. Applications of spinosad or cyfluthrin applied every 10 days will help to control the insect.

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Crape myrtle aphids cause distortion and curling on foliage of crape myrtles

Crape Myrtle AphidsBy: Stanton Gill

Jessica Frakes found aphids on crape myrtle in Chevy Chase, Oscar Peña, Wray Brothers Landscapes, brought in samples from Bethesda, and a nursery from northeast Maryland sent in pictures of crape myrtle aphids that are active this week. Since crape myrtles have become so popular in the landscape we are seeing increasing activity from this aphid. Many people are thinking they have two aphid species present, but what they are seeing is the winged form of the aphid (called alates) and non-winged forms called apterous. There are multiple generations produced throughout the season, so this aphid disperses itself around quickly. Look for distortion and curling on new growth. Control: Check for predators and parasitoids such as syrphid flies, lady bird beetles, and wasps (look for the aphid mummies) because they do a lot to keep aphid populations down. If aphid populations are high enough to warrant treatment, consider horticultural oil or Endeavor which have minimal impact on beneficials.

Yucca Plant Bugs David Keane, Howard County Recreation and Parks, found yucca plant bugs on yucca this week in Ellicott City. There are three generations of the yucca plant bug in Maryland. Look for stippling or chlorotic foliage from feeding damage. Look on the undersides of foliage for the small reddish nymphs. They move fast, so it is best to look for them early in the morning.Control: Horticultural oil can be used to suppress the plant bug population if you have mostly nymphs present. It does not work well against adults. Adults can be controlled using Orthene or a synthethic pyrethroid.

Yucca plant bugs feeding causes stippling and chlorosisPhoto: Jim Baker, North Carolina State University, Bugwood.org

Yucca plant bugs are fast movers so it is best to check plants early in the morningPhoto: David Keane, Howard County Recreation and Parks

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Hawthorn leafming sawfly larvae Photo: Nancy Harding

Cockspur hawthorn with mine injury caused by hawthorn leafmining sawfly Photo: Nancy Harding

Hawthorn Sawfly Leafminer (Profenusa canadensis) Order: HymenopteraBy: Nancy Harding, UMD

Hawthorn sawfly leafminer was found on thornless cockspur hawthorn (Crataegus crus-galli var. inermis) in College Park on May 3. This insect is native to North America, a primary pest of Crataegus crusgalli, and generally attracted to healthy, vigorously growing trees that can tolerate damage.

The adult female hawthorn sawfly leafminer lays individual eggs in the upper epidermis at the base of the leaf early in the spring when the host plant’s leaves are just beginning to unfold and the flowers begin to open. Once the egg hatches, the larva (see photo) feeds on the parenchyma between the leaf surfaces. Their feeding can cause large brown blotches (blister like) which may cover half the leaf . The larvae have flattened bodies with three pairs of legs. They average ~7 mm long when fully grown. Larvae leave the foliage around the middle of June by dropping to the ground. There, they prepare for the winter where they will remain until next spring. For more information about this insect see: Insects that feed on trees and shrubs (second edition)

Control is generally not necessary. The damage is mostly aesthetic and trees recover by mid-summer. Picking infested leaves is not practical and destroying fallen leaves is of no benefit since the insect overwinters in the ground not in the leaves.

Maple Petiole BorerMarie Rojas, IPM Scout, reported on May 3 that maple petiole borer activity is starting this week in Frederick County. She has found flagging growing tips of various Acer species. The damage usually occurs in the spring on new tip growth on 1 to 2 year old maples. Control: Prune out damaged branches.

Maple petiole tip borer larvae cause flagging of leaves and leaf dropPhoto: Marie Rojas, IPM Scout

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Biofouling of Irrigation Systems: Approaches to ManagementBy: Andrew Ristvey

Ornamental nursery growers rely upon high quality water for irrigation of their specialty crops. A water supply with high mineral concentration, suspended solids, pathogens, bacteria and algae creates many “downstream” problems which affect profitability. In this article, I’ll discuss issues of water quality that affect your irrigation systems including living organisms like algae; I’ll relate to you my experiences; and I’ll offer suggestions based on university research with links for more information.

As for my history, I immediately started noticing issues with algae and biofouling of my irrigation lines and emitters within the first season of my doctoral research at WyeREC. My white PVC lines were placed above ground for what I thought was easy maintenance. I was fertigating three times a week with additional clear water irrigation the remainder of the days. Within a month, my emitters were clogging with sheets of blue-green algae which was sloughing off the insides of my pipes. I drained my lines and tried to clear them with bleach injections, rinsing and high volume blow-outs. I then wrapped my lines with insulation and black nursery cover. It helped a little, but I was forever plagued with clogging emitters for the next 4 years. What did I do wrong?

Obviously, having them exposed to sunlight while running fertilizer through the system was my first big mistake; not having a program of injecting sanitizer though the lines on a weekly basis was another. Thinking that doing all of this would have completely prevented any problems would have been my last mistake. While not completely exhaustive, this article will at least summarize some important factors in minimizing biofouling.

Both algae and biofilm (bacteria) are inherent issues irrigation pipes and emitters. Not only will recycled pond water be a source, but well-water also. Minimizing bacterial and algal content at the source can assist directly in further control measures down-stream. Sanitation and proactive maintenance are key to preventing problems.

The first point of control is the source. If it is a recycling pond, several factors may be at fault, including high pond-water nutrient concentrations, pond size and depth (small and shallow) and limited water movement. There are a variety of control options for pond management, but few to none will completely eliminate algae and bacteria from getting into the irrigation system, which is the focus of this article.

Reducing excess fertilization and better irrigation management, including reducing leaching fraction and increasing interception efficiency will minimize the nutrient load entering the pond. Deepening the pond by dredging, especially the edges, will reduce sunlight transmission into the water. Multi-pond systems have been shown to physically remove nutrients, sediments and pathogens better than single pond systems, but a vegetated runoff buffer strip and vegetated runoff inlets into the pond can assist in capturing nutrients if expanding pond system is not an option. Aeration can precipitate iron out of pond-water to reduce iron bacteria fouling. There are options for pond chemical control. Results from the use of barley straw, (which contain algal-growth retardants) are mixed. If used, it should be incorporated early in the year and can initiated with a number of other control methods including aeration. Other suggestions are in Camberato et al (2010), cited below.

Well-water also contains organisms that may foul irrigation lines, but regardless of where the irrigation water originates, water quality needs to be assessed through testing. Dissolved minerals accumulate on surfaces including emitters and plants or provide food for certain bacteria (e.g. iron bacteria). Ranges and problems of dissolved minerals can be found in Lamont (2012), cited below.

Bacterial biofilm from well-water coating the inside of this pipePhoto: Andrew Ristvey, UME

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Water treatment is the next and most effective control measure along the treatment-train. Both physical and chemical approaches can be effective. Screen filters physically remove large particles but sand media filters are a necessity if utilizing water from an above-ground source. Sand filters can remove suspended inorganic (sand) and organic materials (bacteria and algae). Greater water sanitation can be achieved through the use of slow sand filters, but unfortunately, have a high installation costs.

Chemical control and sanitation remains the most cost effective method for management of bacteria, algae, pathogens and minerals. Filters can be placed downstream of chemical injection to capture precipitates and organic particulates. Acid injection neutralizes water alkalinity, controls pH and dissolves mineral deposits like manganese and calcium. Chlorine is injected as a sanitizer to kill disease causing microbes and oxidize and precipitate minerals like iron. The desired concentration of free chlorine is 1 to 2 part per million at the far end of the irrigations system.

Algae usually is less of a problem in buried lines than in white PVC laid above ground, so bury or cover as much piping as possible. A shock treatment of chlorine can be made to irrigation lines if injected at 30 to 60 ppm and held for 30 to 60 minutes. The lines will need to be flushed immediately and completely after treatment and before irrigating plants. Biofilm may continue to slough if fouling is thick. Methods for determining chlorine injection rates can be found in Lamont (2012) cited below. Clogged emitters should either be replaced or cleaned with acid to maintain efficiency and uniform irrigation application.

In in summary, initial planning of irrigation systems should include burying or covering as many pipes to prevent sunlight penetration. There are methods to clean older biofouled pipes, and this should be done at least once twice a season, depending on the severity. Pre-irrigation water treatment of sources, in both ponds and wells is necessary, along with water testing to know what’s in your water and how to treat it.

Finally, using pond water for production of food has its own restrictions, so please be aware of the new federal laws and regulations about food safety.

The below references can be accessed online and have important supplemental information. Be sure to read them. If you have any questions, feel free to contact me at aristvey@umd.edu.

ReferencesCamberato, D. M. and Lopez, R. G. 2010. Commercial Greenhouse and Nursery Production: Controlling Algae in Irrigation Ponds. Perdue Horticulture. HO-247-W https://www.extension.purdue.edu/extmedia/Ho/Ho-247-W.pdf

Haman, D.Z., Clark, G.A., Pitts, D.J.1991. Excavated Pond Construction in Florida. Institute of Food and Agricultural Sciences, University of Florida. Gainesville FL. Extension, Circular 939.http://ufdcimages.uflib.ufl.edu/IR/00/00/32/87/00001/AE01300.pdf

Lamont, B. 2012. Maintaining Drip Irrigation Systems. Penn State Horticulture and Extension. http://extension.psu.edu/plants/vegetable-fruit/news/2012/maintaining-drip-irrigation-systems

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Euonymus Caterpillar (Yponomeuta cagnagella)Jeff Picher, Rainbow Treecare Scientific Advancements, found euonymus caterpillars feeding on Euonymus ‘Manhattan’ shrubs in Laurel on May 4. This caterpillar species feeds later in the season than the euonymus leaf-notcher caterpillar, Pryeria sinica, which you might still see as it is looking for places to pupate at this time. The euonymus caterpillar produces webbing over the ends of branches in which it feeds and has black spots, not stripes. The damage is early in the season so the plant usually recoups quickly and refoliates.

Look for euonymus caterpillars within the webbing on euonymus foliagePhoto: Jeff Picher, Rainbow Treecare Scientific Advancements

Predators Are Active

Dustin Kennedy, Bob Jackson Landscapes, found this praying mantid egg case with nymphs hatching in Owings Mills

Jessica Frakes, Thrive, Inc., found a lady bird beetle adult and newly hatched nymphs in Chevy Chase on May 4

Marty Adams, Bartlett Tree Experts, found this frog, another insect eater, on a blue atlas cedar in Ellicott City on May 3

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Marie Rojas, IPM Scout, reported that while she was looking at some birch with spiny witchhazel gall aphids: “I noticed there were lady beetles present, as usual. But then, I watched as a bunch of syrphid flies were landing on the infested leaves. I’m guessing these were females looking to lay eggs on a great food source.”

Beneficial of the WeekBy: Paula Shrewsbury, University of Maryland

Emerald ash borer and their eggs

It is that time again… As black locust flashes its blooms, Emerald ash borer (EAB) adults should be emerging from ash trees where they were hunkered down for the winter as larvae under the bark. If you see EAB adult activity please contact and let me know where (town, state) and when you saw the adults (pshrewsbury@umd.edu). As many of you have noticed and been affected by, in several counties in MD it seems like EAB is moving through like a fire leaving thousands of dead or soon to die ash trees behind! Such a little beetle and so much devastation!

EAB is an exotic (native to North East Asia) and invasive flat headed beetle (Buprestidae) that has killed millions of ash trees and cost municipalities and states extraordinary amounts of money. Unfortunately, it is not done yet! EAB was first detected in Michigan in the late 1990’s. Maryland was the 3rd state in the U.S. to detect EAB and this was in 2003. Since EAB’s introduction it is now found in 28 states. Until relatively recently, ash (Fraxinus spp.) has been the only genera of trees attacked by EAB in the U.S. However, in 2014 EAB was found attacking white fringetree (Chionanthus virginicus) in Ohio. White fringetree is native to the eastern U.S. and often planted as an ornamental. Dr. Don Cipollini (Wright State Univ. in Ohio) discovered EAB in white fringetree and his research indicates that EAB successfully develops in white fringetree, but interestingly does not successfully develop in the exotic Chinese fringetree also planted in the U.S. The finding of EAB in white fringetree is not surprising since they are in the same family as ash (Oleaceae). EAB has now been found attacking white fringe tree in 4 U.S. states, but to my knowledge not in MD. If you notice any signs of EAB or buprestid borers attacking white fringetree please contact me (pshrewsbury@umd.edu)!

Once adult beetles emerge they begin to feed and you should monitor for chewing damage on the foliage of ash. Adults usually lays eggs under a flap of bark on ash (and white fringe) trees in spring and early summer. The

Adult female Oobius agrili (parasitoid) ovipositing her egg into an emerald ash borer eggPhoto: J. Duan, USDA ARS IRRB

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Emerald ash borer eggs: The top right and bottom left eggs have Oobius agrili (EAB egg parasitoid) developing in them (EAB is dead); the top left and bottom right have EAB larva developing in them. Photo: Jason Hanson, USDA APHIS PPQ, TX

eggs hatch and the tiny larvae bore in to just under the bark. It is here they feed on the cambium tissue and molt through 3 larval stages (L1-L3) and then in the early fall they become “J”-stage larvae. They spend the winter in this stage and in the spring they pupate and emerge as adults in early May when black locust trees are in bloom. The larvae are often referred to as flat headed borers and their feeding damage to the cambium tissue leads to the death of infested trees, usually in 1-3 years.

Like many invasive insects, EAB did not come to the U.S. with any of the natural enemies that attack and suppress EAB in its native range. Also like with many introduced species, classical biological control (CBC) is a common management approach used in the country of invasion (ex. U.S.). CBC is the importation and establishment of new species of natural enemies from the original home of introduced pests in efforts to control the introduced pests. If these introduced natural enemies become established, their populations are often self-sustaining and provide ongoing long term pest suppression. The objective of a CBC approach is usually not eradication. Sometimes, as with EAB, it is to “slow the spread” and/or “reduce the impact” of the invasive species. Multiple parasitoid species (very tiny wasps) that attack EAB in Asia have been brought to the U.S. After extensive studies in quarantine by USDA, four species of wasps have been released in several states that have EAB, including MD. In MD, the Maryland Department of Agriculture (MDA) in collaboration with USDA APHIS, ARS and UMD has been releasing parasitoids since 2009. The Shrewsbury lab (Shrewsbury, Hoban, Abell, Harding, and Jennings; UMD), in collaboration with USDA ARS (Duan; DE) have been conducting research to evaluate the establishment, dispersal and impact of these introduced natural enemies on EAB populations. We are also monitoring the native (to the U.S.) natural enemies that attack EAB.

Since EAB adults will soon be laying eggs (under pieces of bark flake on their host tree) I want to discuss one of the parasitoid species, Oobius agrili (family: Encyrtidae), which attacks the egg stage of EAB. Oobius is a solitary egg parasitoid of EAB. This means Oobius oviposit a single egg into a single EAB egg (some wasps oviposit multiple eggs into their hosts and the larvae have to share the food). EAB eggs are about 1mm in length and usually amber in color. Oobius is tiny (only 1 mm in length) and cannot sting. The Oobius egg hatches inside the EAB egg and consumes the contents of the EAB egg as the wasp develops – killing the EAB egg! Another generation of wasps emerge and attack more EAB eggs later in the season. Oobius overwinters inside the egg of EAB which are under bark flaps of ash. Oobius emerges in the spring / early summer when EAB adults are laying eggs on ash trees and the cycle begins again.

Although Oobius agrili has been released in MD, the recovery (finding parasitized eggs in the wild) has been relatively low (these guys are really tiny!) and impacts on EAB populations or damage are not detectable yet. Monitoring for the tiny parasitized eggs of EAB is difficult so we are researching ways to improve detection techniques. We are optimistic with a little more time and better monitoring techniques we will see greater establishment of Oobius and impact on EAB in MD.

For more information on EAB go to:http://emeraldashborer.info/#sthash.8m08scU8.dpbs http://bugoftheweek.com/

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PLANT PLANT STAGE (Bud with color, First bloom, Full bloom, First leaf)

LOCATION

Baptisia australis ‘Purple Smoke’ First bloom Ellicott City (May 1)Iris ensata (Japanese iris) First bloom Ellicott City (May 1)Liriodendron tulipifera (tuliptree) First bloom Ellicott City (May 1)Penstemon hirsutus (hairy beardtoungue)

First bloom Ellicott City (May 1)

Robinia pseudoacacia (black locust) Full bloom Columbia (May 2)Salvia officianalis Bud Ellicott City (May 2)

Phenology

Degree Days (As of May 3)

Annapolis Naval Academy (KNAK) 523 Baltimore, MD (KBWI) 494 College Park (KCGS) 493 Dulles Airport (KIAD) 548Ellicott City (E247) 479 Fairfax, VA (D4092) 601Frederick (KFDK) 481 Greater Cumberland Reg (KCBE) 487 Gaithersburg (KGAI) 477 Martinsburg, WV (C1672) 433Natl Arboretum.Reagan Natl (KDCA) 671 Rockville (C2057) 614 Salisbury/Ocean City (KSBY) 534 St. Mary’s City (St. Inigoes, MD-KNUI) 610 Westminster (KDMW) 522 Important Note: We are now using the Online Phenology and Degree-Day Models site.

Use the following information to calculate GDD for your site: Select your location from the mapModel Category: All models Select Degree-day calculatorThresholds in: Fahrenheit F Lower: 50 Upper: 95Calculation type: simple average/growing dds Start: Jan 1

The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by University of Maryland Extension is implied.

CONTRIBUTORS:

University of Maryland Extension programs are open to all citizens without regard to race, color, gender, disability, religion, age, sexual orientation, marital or parental status, or national origin.

Thank you to the Maryland Arborist Association, the Landscape Contractors Association of MD, D.C. and VA, the Maryland Nursery and Landscape Association, Professional Grounds Management Society, and FALCAN for your

financial support in making these weekly reports possible.

Photos are by Suzanne Klick or Stanton Gill unless stated otherwise.

Stanton GillExtension Specialist

sgill@umd.edu410-868-9400 (cell)

Paula Shrewsbury Extension Specialistpshrewsb@umd.edu

Ginny RosenkranzExtension Educatorrosnkrnz@umd.edu

Chuck SchusterExtension Educator

cfs@umd.edu

Karen Rane Plant Pathologistrane@umd.edu

Andrew RistveyExtension Specialistaristvey@umd.edu

David ClementPlant Pathologist

clement@umd.edu

Nancy HardingFaculty Research

Assistant

Commercial Horticulture Conferences

Eastern Shore Pest WalkMay 11, 2017Contact: Ginny Rosenkranz, 410-749-6141 To register: https://2017ipmpestwalk.eventbrite.com

MAA/UMD Extension Evening Plant Diagnostic ClinicMay 23, 2017Location: Cylburn Arboretum, Baltimore, MD Contact: 410-321-8082

Pesticide Recertification Conference (Eastern Shore)June 2, 2017Location: Wye Research and Education Center, Queen-stown, MDhttps://2017esprocrastinatorspest.eventbrite.com

Pesticide Recertification ConferenceJune 9, 2017Location: Montgomery County Extension Office, Derwood, MD

MNLGA Nursery Field DayJune 29, 2017Location: Ruppert Nurseries, Laytonsville, MD