TPM/IPM Weekly Report

Transcription

1 TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture September 18, 2015 In This Issue... - Cherry trees in Outdoor insects - Turf damage - Weather update - Redheaded flea beetles - Locust borers - The nutrient nickel - Redheaded pine sawfly - Interiorscape conference - A few other insect sightings Beneficial of the Week Weed of the Week Plant of the Week Phenology Degree Days Announcements IPMnet Integrated Pest Management for Commercial Horticulture extension.umd.edu/ipm 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 Coordinator Weekly IPM Report: Stanton Gill, Extension Specialist, IPM for Nursery, Greenhouse and Managed Landscapes, sgill@umd.edu (office) or (cell) Regular Contributors: Pest and Beneficial Insect Information: Stanton Gill and Paula Shrewsbury (Extension Specialists) and Nancy Harding, Faculty Research Assistant Disease 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) Cherry Trees Look Terrible in 2015 By: Stanton Gill, University of Maryland Extension I received a call on Friday requesting an article on the poor condition of cherry trees in August and September. Poor condition is being defined as lacking foliage on the tree or very sparse foliage present. For cherry trees in many landscapes, 2015 is the second year in a row that they have defoliated early. The weather patterns of spring through mid summer of 2014 and 2015 have created ideal conditions for some of the same foliage diseases that were rampant on ornamental cherry tree species. Many of the cherry trees were damaged by several species of leafspot diseases. There is not much you can do at this time of year which will not make your customers happy. The trees will leaf out next year. The incidence of leafspot infection in 2016 will depend on the frequency of rainfall next spring and early summer during high infection periods. Cherry trees are defoliating early this year Dennis Potts, Potts Consulting

2 Here are some things you can do to reduce the impact: Rake up and destroy fallen leaves. If the crown of the tree is very dense or shaded by other trees, pruning to thin a dense crown or raising branch levels on adjacent trees will improve light and air penetration into the canopy and help reduce new infections. Perform a soil test and provide optimum nutrient levels. This will help suppress certain foliage disease and facilitate recovery should infection occur. Apply preventative fungicide treatments next spring to trees that were damaged last year. This must be done in spring and early summer to prevent the disease infection. Treatments should begin as new growth develops and be repeated during the spring as growth expands. Certain diseases may require additional treatments in summer, if frequent rains continue, to maintain suppression. Watch for Insects When you Drink and Eat Outdoors By: Stanton Gill, University of Maryland Extension We have to very conscious that our pollinator buddies are desperate for sugary substances at this time of year. I received two s this week from people who had unfortunate run-ins with our pollinator buddies. One person was having a beer at an outdoor event and when she went to drink her beer she swallowed a yellow jacket. The yellow jacket was not happy and stung her on the tongue. Her tongue swelled and she asked her beer drinking buds to watch her to see if she passed out if her tongue swelled to close off her air passage. She survived, but the yellow jacket did not. She stomped the heck out of the yellow jacket. She was not in the mood for a lecture on protecting pollinators at this time. The second was a person eating a ham sandwich at a ccookout. A wasp (unidentified because it was consumed) landed on the meat part of the sandwich and the person did not see it when they chomped down. The wasp made it down into her wind pipe and stung her inside her throat. Her friends rushed her to an emergency clinic and she recouped after a couple of hours. She also was not interested in a lecture about protecting pollinators. If you are dining outdoors, during this time of year be very aware that wasps and bees may be attracted to your food and drinks and you need to keep your eye on the food and drink before you chomp down or take a swig. They are still our pollinator buddies but they are hungry for food at this time of year. Damage to Turf Mike Knouse, Macpeak Landscaping Inc., sent a photo of turf that has been damaged. The customer has been seeing this damage for several years and did grub control this season. Raccoons or skunks are possibly causing this damage as they dig for grubs. It is not certain what is causing this damage to turf, but there is a good chance that it is from raccoons or skunks searching for beetle grubs Photo: Mike Knouse, Macpeak Landscaping Inc. 2

3 Weather Update By: Stanton Gill, University of Maryland Extension After I wrote an article in last week s IPM Alert about the 10-week drought, of course, it rained on Saturday. Some areas of Maryland received 3 4 inches of rain. This rain was certainly welcomed. This week we moved into Southern California weather with sunshine and low humidity and cool nights for every day this week. One interesting side effect has been the rains knocked a lot of acorns out of the oaks and they are plentiful this year. We were starting to see dieback of growth on Japanese red maples and a lot of birch have branch dieback. Many other trees and shrubs have been looking very stressed after the 10-week drought. We still need more rain but last weekend s downpour helped. Redheaded Flea Beetles By: Brian Kunkel. Ornamental IPM Extension Specialist, University of Delaware Redhead flea beetles, Systena frontalis, are becoming important nursery pests from Georgia to Connecticut. In the mid-atlantic, larvae are found in root balls of container-grown plants from GDD 50, and are most likely feeding on roots and other organic matter. Azaleas, wild cherry, and Virginia sweetspire are in bloom when larvae are active, and black locust is in full bloom. Plants with larvae in the root balls have not shown any signs of damage. Larvae are found by inspecting the outside of root balls pulled from containers. Adults emerge from GDD 50 and the plant phenological indicators observed were Magnolia grandiflora in flower bud swell to bloom and Ilex verticillata in bloom to full bloom. Adult populations decline around the end of June until mid- to late July. Larval activity for the second generation in the mid-atlantic seems to occur from 1,570 1,860 GDD 50 with adults emerging around 1,878 2,318 GDD 50. Larvae were observed on root balls when Cerastigma plumbaginoides (Blue leadwort) begins to bloom or Lagerstroemia indica x fauriei Hopi (Crape myrtle Hopi ) is in full bloom. There may be a third generation for some areas of the mid-atlantic since there are observations of redheaded flea beetles feeding until mid-october. The GDD ranges and number of generations are part of ongoing research projects. Currently, research suggests this insect overwinters as eggs in the soil-less potting media of various host plants and in the surrounding landscape. Redheaded flea beetles feed on roses, Joe pye weed, grapes, Pennsylvania smart weed, chrysanthemum, forsythia, goldenrod, hibiscus, dahlia, white clover, lamb s-quarter, blueberries, corn, dogbane, pigweed, zinnia, weigela, blackeyed Susans, sedum, salvia and asters among many others. Previously undocumented hosts we found this summer include: 3 Flea beetle feeding causes necrotic areas in leaves (top photo) which eventually drop leaving tattered holes Look for flea beetle larvae in root balls (bottom) Photos: Brian Kunkel, University Delaware Extension Humulus, Chelone, Alchemilla, Cephalanthus and Physocarpus. A survey of different varieties of Hydrangea last summer found that H. macrophylla suffered less damage than H. paniculata varieties. This summer, the survey work was repeated with timed observations on Hydrangea, Itea, and Salvia, and results are being analyzed.

4 Management of redheaded flea beetles has proved difficult for nursery managers. Flea beetles have been the target of multiple insecticide applications over the past few summers. Laboratory research has found Steinernema carpocapsae and S. feltiae to be effective entomopathogenic nematodes; however only S. carpocapsae reduced total numbers of flea beetles found in a field trial. This summer a laboratory research study also found the entomopathogenic fungus, Beauveria bassiana caused mortality to flea beetle larvae. Research projects with entomopathogens is ongoing in field and greenhouse trials. Insecticides with which we have had success managing flea beetles (stage; application method) include imidacloprid (larvae; tablet in soil), cyanotriliprole (adults; foliar), dinotefuran (adults; foliar), bifenthrin (adults; foliar), cyhalothrin (adults; foliar) and thiomethoxam (adults; foliar). Various growers have mentioned efficacy with foliar applications of other insecticides such as carbaryl and acephate. Redheaded flea beetles have a wide plant host range and can be difficult to control Photo: Brian Kunkel, University of Delaware Extension Locust Borers We are finding adults of the locust borer feeding on the pollen of goldenrod flowers which is typical of this native insect at this time of year. Rasma Plato, John Shorb Landscaping, also found this beetle in Odenton on September 17. This beetle is yellow and black so it blends in well with the goldenrod flowers. The larvae of the locust borer feed only on black locust (Robinia pseudoacacia). The adult lays eggs in bark crevices. The larva hatch in fall and begin to feed, but they do not move into the heartwood until spring. There is one generation per year. Damage is less severe in mixed stands of species and on trees over 6 in diameter receiving adequate water. A few locust borer can be found on flowers of goldenrod at this time of year Photo: Rasma Plato, John Shorb Landscaping Nutrient Essentiality: The short story of nickel By: Andrew Ristvey, University of Maryland Extension As early as the mid-1980 s, scientists were discussing the role of the element nickel in plant growth. While the element had been established as essential for cereal crops, evidence was mounting for the addition of nickel to the list of essential nutrients needed by all plants to carry on normal metabolism, growth and reproduction. According to Arnon and Stout, 1939, an essential nutrient is one in which a plant cannot complete its life cycle without, it must exert its effects directly, and no other element can substitute for it. At the turn of the millennium, research in pecan orchards showed that a common growth malady called Mouseear (rounding of normally pointed leaflets), was being caused by nickel deficiency, brought on by years of zinc sprays to correct zinc soil deficiencies. Nickel, zinc and copper are known to enter the plant through the same root-uptake pathways. As with many other nutrients, an overabundance of one can interfere with the uptake of another. Interestingly, the initial cure for Mouse-ear was thought to be a combination of copper and phosphorus, but the application of these would not cure severe symptoms. Close analysis of the phosphorus fertilizer showed that there were traces of nickel as a contaminant (Wood et al., 2004). 4

5 One of nickel s essential roles is in the metalloenzyme urease, enabling the plant to break down urea and preventing it from accumulating in leaves and causing leaf tip necrosis during certain stages of nitrogen metabolism and assimilation. Nickel deficiency includes effects on plant growth like Mouse-ear, plant senescence, and iron uptake (Brown et al., 1987). Also, a variety of researchers have shown that nickel has a role in plant stress resistance (Ahmad and Ashraf, 2011). It is possible that many nickel deficiencies have gone unnoticed in the greenhouse and container nurseries or have been misdiagnosed. According to Wood et al. (2004), deficiency symptoms may include one or a combination of the following symptoms: bunted foliage, dwarfing, delayed budbreak, necrotic zones at the tip of leaves or leaflets, brittle shoots and branches, loss of apical dominance, resetting, crinkle leaf or leaflet margins, slightly necrotic foliage that later turns dark green, reduced growth, short internodes, and reduced flowering. Refinement of some fertilizers has eliminated nickel contaminants. However, I have seen that many complete soluble fertilizers do have nickel salts as an ingredient. Additionally, it is also in well water with concentrations sufficient for plants. Plant nickel concentrations typically range between 0.05 and 5 parts per million. Because nickel is only needed in very low concentrations, toxicity can easily develop if over applied, as with other micronutrients like copper, zinc or boron. Research has shown that there are presently 17 essential plant nutrients, 14 of them being mineral. Still, researchers continue to study other elements, like silicon, and their roles in essential plant nutrition. You can call me for additional information or with any questions you have at x113. Enjoy the fall weather! Redheaded Pine Sawfly Jason Hipp, The Care of Trees, found redheaded pine sawfly larvae feeding on deodar cedar on September 17 in Silver Spring. The larvae feed gregariously. This group feeding of larvae can defoliate whole sections of a pine very rapidly in late August to early September. Control: Prune off tip growth on which they are feeding and destroy. Conserve insecticide will also give control. Feeding by clusters of redheaded pine sawflies can cause significant damage on pines Photo: Jason Hipp, The Care of Trees Interiorscape Conference at Rawlings Conservatory in 2015 In was seven years ago when we last held a conference for the interiorscape industry. We decided it was time to pull together a conference in University of Maryland Extension and MNLGA have set up a whole day of interesting topics for those of you involved with taking care of plants in interiorscapes. The date is October 1, 2015 and the location in the Rawlings Conservatory in Baltimore, Maryland. To register visit the MNLGA website at: 5

6 Insect Sightings These comma butterflies were found in Montgomery County this week; they overwinter as adults Photo: Nancy Woods, McCrillis Gardens Oystershell scale is reported to overwinter in the adult stage; there are two generations of crawlers earlier in the season Photo: Craig Greco, Yardbirds, Inc. The catalpa sphinx moth caterpillars on this catalpa tree trunk have been parasitized by braconid wasps; note the white pupal cases Photo: Terry Martin, Treemovers Barklice nymphs and adults are infesting the trunk of this Japanese maple; they do not feed on living plants Photo: Jason Hipp, The Care of Trees Beneficial of the Week By: Paula Shrewsbury, University of Maryland Emerald ash borer larvae What are they eating and who eats them? Emerald ash borer (EAB) is an exotic (native to Asia) and invasive flat headed beetle (Buprestidae) that has killed millions of ash trees and cost municipalities and states extraordinary amounts of money, and it is not done yet! The adult beetle usually lays eggs under a flap of bark on ash trees, the eggs hatch and the larvae bore just under the bark and feed on the cambium tissue. This feeding damage leads to the death of infested trees. 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 planted as an ornamental in other locations. Don Cipollini (Wright State Univ. Ohio) discovered EAB in white fringetree and his research indicates that EAB successfully develops in white 6

7 fringetree, but does not successfully develop in the exotic Chinese fringetree. White fringetree and ash are in the same plant family (Oleaceae). If you notice any signs of EAB or buprestid borers attacking white fringetree please contact me Like many introduced insects, EAB did not come to the U.S. with any of the natural enemies that attack EAB in its native range. Also like with many introduced species, classical biological control (CBC) is a common management approach. CBC is the importation and establishment of new species of natural enemies from the original home of introduced pests to control those 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 parasitoids (very tiny wasps) have been brought to the U.S. from Asia and after extensive studies in quarantine by USDA three species of wasps have been released in several states that have EAB, including Maryland. One of the parasitoid species, Oobius agrili (Encyrtidae) attacks the egg stage of EAB, and the other two species, Spathius agrili (Braconidae) and Tetrastichus planipennisi (Eulophidae), attack the larval stages of EAB. Just this past year an additional larval parasitoid, Spathius galinae (Braconidae), was approved for release. In Maryland, the Maryland Department of Agriculture (MDA) in collaboration with USDA APHIS has been releasing parasitoids since The Shrewsbury lab (Shrewsbury, Jennings, and Hoban; UMD), in collaboration with USDA ARS (DE) and MDA, have been conducting research to evaluate the establishment, dispersal and impact of these introduced natural enemies and other factors on EAB populations. To date research indicates that Tetrastichus is performing the best. Tetrastichus has established (been recovered following release) at many release sites and dispersed up to 5 miles from release sites! Tetrastichus is an endoparasitoid which means eggs are inserted into EAB larvae (usually late instars), where the eggs hatch, and the parasitoid larvae develop within and consume the EAB larva, ultimately killing the EAB. One EAB larva can produce up to 127 Tetrastichus adults. Tetrastichus survives the winter as mature larvae in EAB galleries. They complete development during early spring, emerge, and continue to parasitize EAB larvae, thus completing at least four generations per year. Impacts of parasitoids have been somewhat low in Maryland, however in other states where EAB have been present longer and CBC releases were started earlier, impacts of parasitoids are greater. I am hoping with a little more time we will see the same pattern of increased impacts of parasitoids on EAB in Maryland. Tetrastichus planipennisi pupae (parasitoid) in an EAB larval gallery Photo: Image by S. Ausmus, USDA ARS Tetrastichus planipennisi adult wasp is about ~4mm in length Photo: David Cappaert, Michigan State University, Bugwood.org 7

8 Weed of the Week By: Chuck Schuster, University of Maryland Extension Sandbur, Cenchrus L, a member of the grass family, is not just one species but can consist of 20 to 25 different species native to warm, sandy areas of North America, North Africa, Asia, Europe, and the South Pacific. It can be found in turfgrass in lawns and sporting sites. Usually found in sandy soils, it can adapt to other soils, especially poorly managed turf. It is usually a spring germinating weed, needing a soil temperature of 52 F which is similar to crabgrass. Sandbur is a shallow rooted, spreading plant that can reach up to 40 inches in total height. It has a flower spikelet that is enclosed in a rounded bur, which is sharp and will detach readily when ripe from the plant on clothing and fur and will be quickly felt by bare feet. Sandbur plants will often be found forming mats that can grow several feet in diameter. The branched stems will be flattened with opposite blades occurring on the stem. The collar is narrow and with in lighter color, and may have sparse long hairs on the margin. It has a diffuse root system. Control is obtained culturally by growing dense turf. It is an opportunistic weed, preferring dry sites and poor fertility. Applications of appropriate amounts of nitrogen to create a dense turf are useful. Pre-emergent herbicides can be used in the spring to further prevent this week from thriving. Oryzalin and Pendimethalin can be used for control of this weed. Plant of the Week By: Ginny Rosenkranz, University of Maryland Extension Heuchera villosa Autumn Bride has a rather plain common name of hairy alumroot, which is a shame as it has such a lovely flower that blooms from August to frost when very little is blooming in a shady garden. This lovely cultivar of a Maryland native has delicate, creamy white flowers clustered into a long cone shape on slender stems that rise above the leaves up to 2 feet high. The rounded heart-shaped leaves are velvety smooth, medium to chartreuse green with 5-7 triangular lobes. Autumn Bride prefers to grow with morning sun and afternoon shade for best flowering and keeps its foliage all year long in most of Maryland counties. Spent flowers should be removed to encourage more blooms which in turn encourages more hummingbirds and butterflies into the garden. It grows best in organically rich medium moist, but well drained soils. Once established Autumn Bride is tolerant of high heat, humidity and drought and is listed as resistant to deer. Autumn Bride is cold hardy from USDA zones 3-8 and will form a mound of foliage inches high and 18 inches wide. Heuchera villosa Autumn Bride is a versatile plant that can find a place in the landscape in woodland gardens, along a pathway, as an edging plant, in mass plantings to create a groundcover and as a cut flower. Pests include weevils, foliar nematodes, powdery mildew, rust and leaf spots. 8 Sandbur often forms mats and can grow several feed in diameter Photo: Ginny Rosenkranz, UME Heuchera villosa Autumn Bride blooms from August to frost in the shade Photo: Ginny Rosenkranz, UME

9 Degree Days (As of September 17) Baltimore, MD (BWI) Dulles Airport Frostburg, MD Martinsburg, WV National Arboretum Reagan National Salisbury St. Mary s City To check degree day (DD) accumulations in your local area go to: Note: degree days reported in this newsletter use a base temperature of 50 F, a start date of January 1st, and the date of monitoring as the end date. Upcoming Conferences: Interiorscape Conference October 1, 2015 Location: Rawlings Conservatory, Baltimore, MD Community Forestry Workshop October 2, 2015 Location: Carroll Community College, Westminster, MD 4 th Annual TreesMatter Symposium November 4, 2015 Location: Silver Spring Civic Center, Silver Spring, MD December 10, 2015 Pest Management Conference Details will be posted late September or early October CONTRIBUTORS: Stanton Gill Extension Specialist sgill@umd.edu (cell) Paula Shrewsbury Extension Specialist pshrewsb@umd.edu Karen Rane Plant Pathologist rane@umd.edu Chuck Schuster Extension Educator cfs@umd.edu David Clement Plant Pathologist clement@umd.edu Andrew Ristvey Extension Specialist aristvey@umd.edu Ginny Rosenkranz Extension Educator rosnkrnz@umd.edu Nancy Harding Faculty Research Assistant 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. The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by University of Maryland Extension is implied. 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.