tpm/ipm weekly report · stanton gill, extension specialist, ipm for nursery, greenhouse and...
TRANSCRIPT
for Arborists, Landscape Managers & Nursery Managers
Commercial Horticulture July 11, 2014Coordinator Weekly IPM Report: Stanton Gill, Extension Specialist, IPM for Nursery, Greenhouse and Managed Landscapes, [email protected]. 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 (Regional 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
TPM/IPM Weekly Report
Weather UpdateBy: Stanton GillThe weather for the July 4th weekend could not have been better – cool and dry. It was refreshing weather and many people headed to the mountains or the ocean. Ocean City, MD was packed wall to wall with people over the weekend and Western Maryland had a surge of people visiting Deep Creek Lake.
We return to typical Maryland weather this week with temperatures reaching into the mid-90 °F range. Keep in mind we are at the hot part of summer with a lot of high light and this time is when plant material needs irrigation. While people are away on vacation much of the plant material in containers will likely dry up and there should be demand for replacement plants later in the summer. It all ends up good for the horticulture industry.
- Weather update- Sad news- Green June beetle- Emerald ash borer- Pesticide container recycling- Ambrosia beetles- Japanese beetles- Boxwood leafminer- Aster yellows- Caterpillar on oak- Scale update- Cherry trees and leaf drop- Main peachtree borer- Honeylocust spider mites
Beneficial of the WeekWeed of the WeekPlant of the WeekPhenologyDegree DaysAnnouncements
IPMnetIntegrated Pest Management for
Commercial Horticulture
extension.umd.edu/ipm
Greenhouse Biological ProgramAugust 6, 2014
Stormwater Management ProgramAugust 20 and 21, 2014
2
This digger wasp, Scolia dubia, has two distinct spots on the reddish brown part of its abdomen
Green June beetles are active in turf in Ellicott City this week
Emerald Ash BorerDick Bean, Maryland Department of Agriculture, sent an update on EAB in Maryland:EAB has been detected for the first time in Carroll County and Baltimore City on purple traps. Expansion in St. Mary’s County extends to Lexington Park and in Calvert County to St. Leonard’s. A current known distribution can be found at http://mda.maryland.gov/plants-pests/Documents/2014MD_EAB_Trap_Survey.pdf
Green June BeetlesGreen June beetle activity started in turf areas early this week at the research center in Ellicott City. At this time, adults are hovering over grassy areas looking for mates. If you have trees with wounds, you might find green June beetles feeding on the sap. Green June beetles are usually not a pest on ornamentals. Adults mainly feed on ripe fruit, especially figs. These beetles are more of a problem in turf as a result of tunneling and mounding of soil and some root feeding.
Maintaining healthy turf can help mask the damage from tunneling. It might be necessary to overseed damaged areas in the fall. Steinernema spp. and Heterorhabditis spp. are insect parasitic nematodes that can be used to suppress grubs. Keep an eye out for the digger wasp, Scolia dubia, epsecially in August. The adult females of this wasp lay eggs on green June beetle grubs. Paula Shrewsbury covered this wasp in the August 23, 2013 report.
Maryland Department of Agriculture Pesticide Container Recyling
MDA has a brochure on the dates and details of the pesticide container recycling program which is available at: http://mda.maryland.gov/plants-pests/Documents/recycle.pdf
Sad NewsTwo members of our green industry passed away last weekend. Damian Varga was with Scientific Plant Services and Brian Akehurst was president of Akehurst Landscape Service, Inc., Our condolences go out to the family and friends of Damian and Brian.
3
Little leaf linden is one of the favored hosts of Japanese beetles
Ambrosia BeetlesBy: Stanton GillNursery owners may find this interesting. A nursery owner had a plantings of 75 straight species of London planetrees. In his nursery next to this planting, he had 100 of London planetree ‘Exclamation’. The same soil type is at both sites. The straight species and the ‘Exclamation’ were all planted at the same time in the spring of 2013. The straight species all had frost cracking (a result of the severe winter of 2014) on the trunk while the ‘Exclamation’ had no frost cracking. The grower had 65 of the 75 straight species London planetree infested with ambrosia beetles. The trees were either dead or so badly damaged he had to destroy them. The interesting thing is the ‘Exclamation’ cultivar had no ambrosia beetle damage. This situation may help support the theory that cold injury and frost cracks play a role in infestation of Xylosandrus on some species of trees.
The following is the information on London plane tree ‘Exclamation” from Morton Arboretum that I pulled from the web. This hybrid selection of the London planetree resulted from a controlled cross made by Dr. George Ware at the Morton Arboretum in Lisle, Illinois, between P. orientalis (naturally anthracnose-resistant) and an anthracnose-resistant P. occidentalis parent. It was selected for its uniform, upright-pyramidal habit, which is conical in its youth; a strong central leader; and attractive foliage. This plant is densely branched, has a moderate growth rate, is light-fruiting, and shows resistance to frost cracking and anthracnose. It has the attractive exfoliating bark expected of planetrees and will measure 60’ in height with a 30’ spread. It is hardy in Zones 4-8.
More on ambrosia beetles: Bill Marose, IPM Scout, found another flight of ambrosia beetles at an orchard in Harford County. Bill found a couple of dozen in each of two funnel traps and two cherry trees.
Japanese Beetle UpdateBy: Stanton GillJapanese beetle populations are inflicting heavy damage in several parts of the state. Reports we are receiving on adult beetles are increasing with heavy damage on little leaf linden, roses in general - with Knockout rose planting being a magnet for the beetles, flowering plums, zinnias, and Rose of Sharon all topping the list of favored plants. One interesting development is that there is an increasing number of people growing hops on wires and poles for making home brew. The hop foliage is highly attractive to Japanese beetles. Neem products labeled for food crops can give some protection, but most need to reapplied every couple of days. Since the hops grow on vines up to 20 - 25 ft high, I am not sure how to easily get the material onto the foliage.
I am amazed at how many people are still placing out Bag-A –Bug traps to trap out the adult beetles. If your customers are using the traps, then have them place the traps far away from the plant material on which the beetles like to feed.
I mentioned in last week’s IPM Alert that Acelepyrn (Chlorantraniliprole) was a new class of insecticides that was extremely safe and extremely expensive for Japanese beetle control. Chlorantraniliprole is also sold for the fruit industry under the name Altachor and is labeled for use on chokeberry (Aronia), grape, gooseberry and blackberries. So far, I have found it to be very effective on highly attractive fruit such as grape and plum trees.
4
Boxwood LeafminerBy: Stanton GillA grower called in to inquire about the best time to use Avid (Abamectin) for controlling boxwood leafminer. He noted the label said to apply just after the adults emerged. The grower questioned why you would apply it to control the larvae at this time since the female had to lay an egg into the foliage and it would have to hatch to kill the larvae.
I checked with some fellow entomologists on this question. Dan Gilrein of Cornell University said they had conducted trials using Avid in mid-summer and it gave poor control.
David Shetlar, Ohio State University, brought up some interesting points. Here is the advice from David: From what I understand about this pest, the larvae only make a very small mine upon hatching from the egg. They then go into summer aestivation (resting inactive stage) while the boxwood leaf makes additional callous tissues (these look like tiny blisters on the leaf undersurface). In September through November, the larvae resume feeding and make a large mine with a thin covering of epidermis on the lower surface. The larvae stop feeding when regular freezing temperatures arrive, then feed briefly in March into April before pupating.
I have had commercial applicators who have good success applying some of the neonics in mid-September into early October to catch the larvae as they resume feeding. I would suspect that Avid would do the same during this time period. It would be worth the effort (even if only a small block of plants are treated) to see if a late season application will stop the larvae before they seriously damage the leaves. Fall applications of imidacloprid have prevented psyllid egg hatch the following spring and I’ll bet that Avid may have the same activity.
The label evidently says to apply at adult activity so you would control the newly hatching larvae for the short time they feed. This window of opportunity has past until next year. Looks like the other time to apply this material would be in September to kill the larvae as they start feed in the foliage in fall.
Aster yellows causes stunting, plant yellowing, and distorted leaves and flowers
Aster YellowsWe received a picture of Echinacea showing symptoms of aster yellows, a disease caused by a phytoplasma. Aster yellows is spread by leafhoppers, especially the aster leafhopper, which migrates northward each year from the southern US. When a leafhopper feeds on an infected plant, the leafhopper becomes “infected” with the phytoplasma and remains infected and able to transmit the disease throughout its life.
There are numerous strains of aster yellows infecting over 300 species of plants, including ornamentals such as aster, coneflower, and rudbeckia; and vegetables such as carrot, celery and lettuce. Symptoms include overall yellowing and stunting of infected plants, as well as distortions of leaves and odd, leaf-like structures that develop in flowers.
Weeds that may harbor the disease include plantain, dandelion, and other broad-leafed weeds. Remove symptomatic plants and keep weeds down around susceptible flowers. Insecticides are generally not effective in managing this disease.
5
Caterpillar on OakRichard Chaffin, The Brickman Group, found a pink-striped oakworm feeding on pin oak in Essex on July 10. These caterpillars feed gregariously (in groups) on oak.
Pink-striped oakworms feed gregariously on oaksPhoto: Richard Chaffin, The Brickman Group
Scale Updates*:Pine Needle Scale, Chionaspis pinifoliae (armored scale)Monitoring pine needle scale on Pinus mugo in Bowie found females with eggs indicating the second generation crawlers will soon follow. There are two generations a year. As of Tuesday, July 8th the Degree Days were 1322 DD. We will continue to monitor this scale and let you know when the crawlers are active. Host Plants: Mugo and Scotch pine are preferred, but other pines and spruce are frequently attacked.
White Prunicola Scale, Pseudaulacaspis prunicola (WPS - armored scale)We are monitoring white prunicola scale on Prunus × yedoensis (Yoshino cherry) in Laytonsville. As of July 8th we found females with eggs indicating the second generation of crawlers will soon follow. There are three generations a year. Degree Days in Laytonsville were 1544 DD. We will continue to monitor this scale and let you know when crawlers are active. Host plants: Preferred hosts include Prunus, especially Japanese flowering cherry, lilac, and privet.
Pine Oystershell Scale, Lepidosaphes pini (armored scale)We are monitoring pine oystershell scale (also called Oriental pine scale) on Pinus densiflora (Japanese red pine) in Laytonsville. As of Tuesday July 8th, 3rd instar females and males were found, but no eggs or crawlers. Degree Days in Laytonsville were 1544 DD. The adult female cover is oyster-shell shaped, straight or slightly curved, moderately convex, and light brown. The male cover is shorter and narrower than the female cover and is the same color and texture. The scale is usually found near the needle sheath. We will continue to monitor this scale and report when crawlers are active.Host plants: Pinus spp.
*Degree data totals as per Weather Channel website at http://www.weather.com/outdoors/agriculture/growing-de-gree-days/USMD0045
If you are scouting sites with an infestation of white prunicola scale, now is the time to look for the next generation of crawlers
6
An adult hunting wasp, Ammophila zanthoptera, with a forage looper caterpillarPhoto: Whitney Cranshaw, Colorado State University, Bugwood.org
Beneficial of the WeekBy: Paula Shrewsbury, UME
Hunting wasps are great predatorsLast week I discussed a wasp, Monobia quadridens, in which the female captured caterpillars and used them to stock her nest with food for her young. Several people got back to me informing me they have seen this behavior and how cool it was to watch the wasp catch caterpillars! I wanted to share a little more information on these “hunting wasps”. Many of these Hymenoptera are in the Sphecidae or Vespidae families. Hunting wasps feed on nectar from flowers as adults and hunt for prey to feed to their young. Prey may include caterpillars, leafhoppers, crickets, beetles, spiders and more. Wasps can be somewhat specialized in what they eat. Some wasps are solitary like the Monobia discussed last week where a single female maintains her own nest. The cicada killer wasp is one that with which most of you are familiar and one of the largest. The female cicada killer wasp lines her nest with annual or dog day cicadas. Although she is large, like most solitary wasps they are not aggressive and rarely sting. Other wasps are social where many individuals work together, individuals make up different castes (ex. queen, workers, drones), and the colony resides in a nest together. Common social hunting wasps include paper wasps or yellow jackets. Nests may be made of “paper” or mud and found in trees or house eaves, or nests may
Honeylocust Spider MitesSteve Sullivan, The Brickman Group, is finding heavy infestations of honeylocust spider mites in Baltimore County. This native spider mite feeds only on the leaves of honeylocust (Gleditsia triacanthos). There are several generations a year in this area. Honeylocust that are growing in hot dry sites are most susceptible to injury from this pest.Monitoring: Examine foliage of honeylocust. Use a piece of paper on a notebook and tap the leaves sharply over the paper and look for the mites using a 10 -16 X magnifier.Control: When temperatures are high, it is not the best time to apply a miticide. If making a treatment, be sure to irrigate and make the application early in the morning. Materials for mite control include abamectin (Avid) fenpyroximate (Akari), bifenazate (Floramite), hexythiazox (Hexygon), spinosad (Conserve), pyridaben (Sanmite) and horticultural oil.
Cherry Trees and Leaf DropAs a follow-up to the information on premature leaf drop of ornamental cherry foliage, Stephen Griner, Scientific Plant Services, reported that he is seeing several cherry trees with early leaf drop in Towson, Bel Air, and Ellicott City.
Main Peachtree BorerBy: Stanton GillWe are pulling in main peachtree borers in pheromone traps this week. Susceptible cherry laurels, flowering plums, and ornamental peaches that are under stress should be protected. In landscapes Permethrin and bifenthrin are both labeled for protectant trunk applications. This borer tends to strike trees low on the trunk.
7
be underground in holes or burrows that have been abandoned by small animals. Social wasps aggressively defend their nests by stinging. Social wasps capture caterpillars or other insects that they bring back to the nest where an insect “paste” like substance is made and fed to the young. The images show just a few examples of wasps that make good predators. The combined efforts of solitary and social wasps have an impact in reducing herbivorous insect populations and the potential damage they might cause. So remember when you see wasps flying about they are contributing to biological control. The wasps are interesting to watch. Just do not make the social wasps feel threatened!
Weed of the WeekBy: Chuck Schuster, UMECommon dayflower, often called Asiatic dayflower, Commelina communis, is an erect creeping annual found in damp or shaded areas in nurseries and landscapes. Common dayflower has a fibrous root system and often roots at the nodes. Leaves are lanceolate in shape with parallel leaf veins. The leaves most often have hairs on both upper and lower sides. Leaves are up to four inches in length and approximately one half to one and one half inch wide. Leaves have no petiole and clasp the stem, often with hairs in this region. Stems may grow to two and one half feet in length, with nodes being thicker and developing roots when in contact with the soil or damp mulch. Flowers are on a long flower stalk that arises from the area between the stem and the leaf axils. Each flower has one white petal and two blue petals which appear for only one day, thus its name. It is a monocot, (lilies and daffodils) and with its blue flower generates identification mistakes very often.
Control of common dayflower can be achieved using post emergent herbicides including bentazon (Basagran, Prompt, Lescogran), and in landscape settings glyphosate products or other non selective post emergent products. Use care in landscapes with post emergent products to avoid contact with desired plant species to avoid damage to desired plant species.
Common dayflower can be mistaken for a dicot, but it is actually a monocot (left)
Leaves do not have peitoles and clasp the stem (right)
The photo shows the two prominent blue petals, but the lower white petal is barely visible
8
Buddleia ‘Miss Molly’ is sterile and does not reseedPhotos: Ginny Rosenkranz, UME
Plant of the WeekBy: Ginny Rosenkranz, UMEBuddleia ‘Miss Molly’, butterfly bush or also called a summer lilac, is more compact than many other Buddleia and is sterile so will not reseed all over the garden like the older varieties. This dark sangria red bloomer starts flowering in mid-summer and continues to bloom into the fall until the first hard frost. If the plants are grown in the warm southern counties of Maryland, the flowers will be a darker red than the cooler northern counties which will bloom a magenta color. Plants grow vigorously three to five feet tall and wide with fragrant flower clusters almost six inches long at the tips of each branch. After the primary flower cluster is done, two side clusters begin to bloom, creating a long lasting flowering time. Flowers can be used as cut flowers which also encourages even more flowering. The foliage is broadleaf and deciduous, green to gray green in color. Plants are hardy in USDA zones 5-10 and do best in full sun and moist but very well drained soils for best flowering. ‘Miss Molly’ is drought, heat, humidity and deer resistant, and like all buddleias, ‘Miss Molly’ attracts both butterflies and hummingbirds to the garden. Plants should be pruned down to 1/3 of their height each spring to promote branching and better flowering, as it only blooms on new growth. ‘Miss Molly’ is a cross between ‘Miss Ruby’ which produces very few seeds and ‘Attraction’ by Dennis Werner with Proven Winners at JC Raulston Arboretum of North Carolina. Plant as a specimen or as a border, in foundation plantings or in a cottage garden and of course in a butterfly garden. ‘Miss Molly’ can also be planted in a large container. Pests include spider mites, aphids and downey mildew.
PLANT PLANT STAGE (Bud with color, First bloom, Full bloom, First leaf)
LOCATION
Monarda fistulosa First bloom July 9 (Ellicott City)Phlox ‘Sherbert Cocktail’ Full bloom July 8 (Ellicott City)Veronicastrum virginicum First bloom July 8 (Ellicott City)
Degree Days (As of July 10) 2014 2013 2012 2014 2013 2012Baltimore, MD (BWI) 1606 1658 2034 Dulles Airport 1533 1693 1962Frostburg, MD 994 1054 1264 Martinsburg, WV 1575 1571 1856National Arboretum 2013 1941 2353 Reagan National 2013 1941 2353Salisbury 1823 1881 2098 St. Mary’s City 1696 1801 2155
To check degree day (DD) accumulations in your local area go to: http://www.weather.com/outdoors/agriculture/growing-degree-days/USMD0100
Note: degree days reported in this newsletter for various pests use the Weather.com web site, a base temperature of 50 °F, a start date of January 1st, and the date of monitoring as the end date.
Stanton GillExtension Specialist
Paula Shrewsbury Extension [email protected]
Ginny RosenkranzExtension [email protected]
Chuck SchusterExtension Educator
Karen Rane Plant [email protected]
Andrew RistveyExtension [email protected]
David ClementPlant Pathologist
hgic.umd.edu
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.
Upcoming Conferences
PGMS Green Industry Professional Field DayJuly 17, 2014Location: American University, Washington D.C.Green Industry Field Day Brochure
Virginia/Mid-Atlantic Regional Aquaculture Best Management Practices Training WorkshopJuly 23, 2014 2014 8:30 AM – 4 PM.Location: Hampton Roads Agricultural Research and Extension Center 1444 Diamond Springs Road, Virginia Beach, Virginia.Free, lunch provided. Pre-registration required: Attendance will be limited to first 50 pre-registrants. To register please contact: Gail Jamison: 1-757-727-4861, [email protected]
Program components:What are Aquaculture Best Management Practices (BMPs)?; FDA aquaculture regulations, guidelines, and future trends/considerations; State regulators/regulations, and VDACS Fish Health; All about Aquaculture Feeds; BMPs for hatcheries, raceways, ponds, cage culture, hydroponics/aquaponics, recirculating aquaculture systems, harvest and post-harvest handling
PANTS14 - Penn Atlantic Nursery Trade ShowJuly 30-31, 2014Pennsylvania Convention Center, Philadelphiawww.pantshow.com or 732-449-4004
Greenhouse Biocontrol Conference***August 6, 2014 Location: Maritime Institute, Linthicum, MD
Fertilizr Applicator Recertification SeminarLocation: Maryland Department of Agriculture, Annapolis, MDTime: 9:30 a.m. to 11:30 a.m.Choose any one of the following dates for recertification:August 7, 2014 or September 3, 2014Seating is limited, register now. Cost: $12, which includes breakfastRegistration with payment is required no later than one week before the class date. For more information, call 410-841-5959.
Stormwater Management Program***August 20 and 21, 2014
TWO Locations: August 20 - Montgomery County Extension Office, Derwood, MDAugust 21 - Robinson Nature Center, Columbia, MD
*** For brochures and registration information on these programs