Protect and Conserve Pollinators and Natural Enemies in our Landscapes

Transcription

1 Protect and Conserve Pollinators and Natural Enemies in our Landscapes Dr. Rebeccah Waterworth Department of Entomology University of Maryland, College Park, MD Montgomery County Monthly Meeting August 2, 2018 Today s topics Natural enemies and pollinators Features and practices that: Reduce abundance and diversity of natural enemies and pollinators Disrupt biological control and pollination services Result in pest outbreaks, pollinator decline Practices to protect and conserve beneficial insects Insects provide vital ecosystem services Critical links in food webs and food chains Nutrient recycling, decomposition Biological control istockphoto/jenny Waterson Natural Enemy Diet: Specialists An organism that feeds on only one type of prey or host Spider mite destroyer lady beetle All photos by Jack Kelly Clark Pollination 1

2 Natural Enemy Diet: Generalists An organism that feeds on more than one type of prey or host Natural Enemy Diet: Omnivores An organism that feeds on both animal (insect prey) and plants (nectar and pollen, seeds) Bradley Higbee, Paramount Farms, bugwood. org Jeremy Sell Predators Lady Beetles Coleoptera: Coccinellidae 2

3 Lady beetle larva feeding on an aphid Green Lacewing Neuroptera: Chrysopidae Video by M.J. Raupp, UMD Flower or Hover Fly Diptera: Syrphidae Assassin bugs Hemiptera: Reduviidae 3

4 Small Predators! Dance Fly Parasitoids Lady beetle, Diomus Main prey items are aphids 1.5 mm long C. Brodo, UMD Really Small Parasitoids! Aphid mummies Bob Cammarata 4

5 What is a pollinator? A biotic agent that moves pollen from male anthers of a flower to the female stigma of a flower What is a pollinator? Beetles Pollinators include vertebrates: 1. Birds (hummingbirds and sunbirds) 2. Bats 3. Mice Pollinators include invertebrates: 1. Thrips (some) 2. Ants 3. Beetles 4. Flies (especially flower flies) 5. Butterflies and moths 6. Bees Slide courtesy of P. Shrewsbury What is a pollinator? Flies What is a pollinator? Butterflies and Moths Video by M.J. Raupp, UMD Slide courtesy of P. Shrewsbury Slide courtesy of P. Shrewsbury 5

6 What is a pollinator? Bees 4,000 species of bees in the U.S. and Canada ~425 species of bees occur in Maryland Social bees honey bees, bumble bees Solitary bees mason bees, leafcutter bees All bees build nests and stock them with a nutritious mixture of pollen, nectar, and saliva before laying their eggs Specialist vs Generalist Bees Specialist or oligolectic Pollen specialist collecting pollen from a single plant family or genus 20-25% of bees are oligolectic Lasioglossum oenotherae Hadel Go / discoverlife.org Evening primrose specialist Generalist or Polylectic Pollen generalist collecting pollen from multiple plant families Xylocopa virginica Hadel Go / discoverlife.org > 50 different flowering plants Ground-nesting bees Plasterer bees Digger bees Miner bees Cavity-nesting bees Leaf cutter bees B.Castro, TAMU Slide courtesy of P. Shrewsbury, UMD Slide courtesy of P. Shrewsbury, UMD 6

7 Today s topics Natural enemies and pollinators Features and practices that: Reduce abundance and diversity of natural enemies and pollinators Disrupt biological control and pollination services Result in pest outbreaks, pollinator decline Practices to protect and conserve beneficial insects Practices that Reduce the Abundance of Natural Enemies and Pollinators Natural Enemies Pesticide applications Pest introductions Environmental stresses Vegetational change Cultural practices Pollinators Pesticide exposure Pathogens and parasites Climate change Limited or poor quality floral resources Reduced or degraded nesting habitat Practices that Reduce the Abundance of Natural Enemies and Pollinators Practices that Reduce the Abundance of Natural Enemies and Pollinators Natural Enemies Pesticide applications Pest introductions Environmental stresses Vegetational change Cultural practices Pollinators Pesticide exposure Pathogens and parasites Climate change Limited or poor quality floral resources Reduced or degraded nesting habitat 7

8 Pesticides, pollinators, and natural enemies Non-target effects -Direct exposure -Indirect exposure Protecting and enhancing pollinators in urban landscapes for the US North Central Region Provides information for landscapers and gardeners who want to attract pollinators and protect them when implementing pest management tactics Plant lists Pesticide treatments, timing, and choices ces/how_to_protect_and_incre ase_pollinators_in_your_lands cape Image by M. Raupp, UMD Organic Materials Review Institute OMRI - a nonprofit organization founded in Linden (Tilia spp.) trees in flower wikipedia Japanese beetle feeding on linden leaves Provides organic growers, manufacturers, and suppliers an independent review of products intended for use in certified organic production, handling, and processing. Acceptable products are OMRI Listed and appear on the OMRI Products List or OMRI Canada Products List. Choices Timing April May June July August September October 357 insecticides for a wide variety of pests, including those in landscapes From: Protecting and enhancing pollinators in urban landscapes for the US North Central Region. Smitley et al Foliar spray applied if defoliation is expected to exceed 30% of total leaf area 8

9 Recommendations: Pesticide Use Choose pesticides wisely - Choices Low toxicity, selective, short residual activity, IGR EPA Reduced Risk entries as of May Organic Materials Review Institute (OMRI) - listed pesticides Read and follow label directions carefully! Avoid activities that are harmful to natural enemies and pollinators Timing Do not apply pesticides to plants / lawns in bloom Do not spray flowers with fungicides Make applications in the evening, night, or early morning Integrate alternative control measures (IPM) Cultural, mechanical, or biological tactics Today s topics Natural enemies and pollinators Features and practices that: Reduce abundance and diversity of natural enemies and pollinators Disrupt biological control and pollination services Result in pest outbreaks, pollinator decline Practices to protect and conserve beneficial insects Conserve Pollinators and Natural Enemies Diversity of flowering plants that provide overlapping, season long bloom and alternate prey (food) Nesting and egg laying sites Shelter without disturbance for overwintering Natural Enemy Diets Specialist Generalist Omnivores Bradley Higbee, Paramount Farms, bugwood. org Jeremy Sell 9

10 Many natural enemies are pollinators Many pollinators are natural enemies Practices to conserve natural enemies and pollinators should be similar Plant species richness Structural complexity P.M. Shrewsbury, UMD M. J. Raupp, UMD Refuges Microclimates Alternate food sources (prey, nectar, pollen) Plant Selection Native or Exotic Function of the plant Will it survive / thrive in the habitat? Quality and availability of the pollen and nectar What does it attract and support? Specialist insects associated with natives Generalist insects feed on diverse plant species (native and non-native) Plant Selection: Bloom period Maintenance requirements Avoid invasive or aggressive species From: Xerces Society Pollinator-Friendly Plants Mid-Atlantic Region at: 10

11 Plant Selection: Floral and Plant Architecture Plant Selection: Type and Species Plant / flower species Research-based information Use available resources Sweet Alyssum Gaillardia Switchgrass Trees, shrubs, vines, wildflowers, herbs, perennials, annuals Annuals tend to not be good sources of nectar and pollen, but there are exceptions (see: Protecting and enhancing pollinators in urban landscapes ) Liatris Coreopsis Yarrow Diversify! Plant Selection Native plants (in Michigan) Plant Selection Pollinators and natural enemies Table of plants, bloom times, and rating of attractiveness to natural enemies and pollinators Not native in MD according to USDA Plants Database Available at: ativeplants/uploads/files/e 2973.pdf 11

12 Recommended native plants that are: highly attractive to pollinators such as native bees, honey bees, butterflies, moths, and hummingbirds well-suited for small-scale plantings: Gardens Business and school campuses Urban greenspaces Farm field borders Plant Selection Plant Selection Size and arrangement of landscape beds How large and how close to one another do flowering patches have to be? It is better that patches are bigger and closer to others than smaller, isolated patches Within a patch, it is better that plants are clumped together rather than left as single plants However, every plant counts! Plant Selection Floral Resources: Trees and shrubs that are attractive to bees AND relatively pest free 1. St John s wort 2. Clethra 3. Dwarf fothergilla 4. Itea 5. Glossy abelia 6. Vitex 7. Seven sons flower tree 8. Caropteris List from the Horticulture Research Institute publication, Bee Health BMPs: Version 1.0 Flower of seven sons flower tree 12

13 Mean Diversity of Spp / Treatment (±SE) Mean / treatment (±SE) 8/2/2018 Efforts towards the conservation of natural enemies and pollinators Based on research that demonstrated attraction of pollinators and/or natural enemies Seed mix of annual and perennial flowers 19 spp. Select percentage seed of each species Commercially available seeds Something blooming throughout the season Colias sp on Symphyotrichum novae-angliae Shrewsbury and Waterworth, current study Results: Pollinator Abundance F = 2.09, df = 1, 4, P = 0.24 Conservation Strip Grass Data were log 10 transformed. Plot was treated as a random effect. One-way ANOVA Pollinators included: Bees (Apidae, Megachilidae, Halictidae, Colletidae, and Andrenidae) Non bees: Butterflies (Hesperiidae and Pieridae Beetles (Cantharidae) Flies (Syrphidae) Results: Pollinator Diversity Conservation Strip Grass 10 * Two-tailed t-test: Larger diversity of 8 pollinators collected in conservation strips 6 (t = 3.33, df = 6, P = 0.02) Treatment Maryland native plant species tested to determine their attractiveness to natural enemies Common name Scientific name Family Common milkweed Asclepias syriaca Asclepiadaceae Butterfly weed Asclepias turberosa Asclepiadaceae Threadleaf coreopsis Coreopsis verticillata Asteraceae * Hyssopleaf thoroughwort Eupatorium hyssopifolium Asteraceae * Spotted horsemint Monarda punctata Lamiaceae * Narrowleaf mountain mint Pycnanthemum tenuifolium Lamiaceae * Skullcap Scutelaria integrifolia Lamiaceae Switchgrass Panicum virgatum Poaceae Indiangrass Sorghastrum nutans Poaceae Little bluestem Schizachyrium scoparium Poaceae Frank, Shrewsbury, & Esiekpe, 2008 Environmental Entomology 13

14 Winners - MD Native Insectary Plants Examples of Natural Enemies Whitney Cranshaw Coreopsis verticillata Pycnanthemum tenuifolium Robert H. Mohlenbrock, USDA SCS groups.ncf.edu Eupatorium hyssopifolium Monarda punctata Frank, Shrewsbury, & Esiekpe, 2008 Environmental Entomology Jeremy Sell David Cappaert, bugwood.org Susan Ellis, bugwood.org Frank, Shrewsbury, & Esiekpe, 2008 Environmental Entomology Howard Waterworth Residential Flower Garden Fetridge et al (2 yr study) Gardens dominated by perennial flowering forbs and shrubs and a few early-blooming trees o Few native plant spp o Most plants of European origin and available commercially Collected 110 spp of bees with bee bowls and by hand o 94% were N. Am. natives o 93% of spp were generalists o 65% of spp were ground-nesting Take home message: 1. Suburban gardens still have high diversity of bees 2. These habitats appear to support low numbers of specialist bees. From Lerman & Milam 2016 Lawn-dominated yards Take home message 1. To conserve pollinators: Lerman and Milam 2016 (2 yr study) collected 111 spp of bees (95% were N. Am. natives) 63 spp of spontaneous flowering plants in lawns mostly dandelion and clover 90% of bee spp were generalists 73% of bee spp were groundnesting avoid practices associated with high-input lawns incorporate weed diversity 2. Low-input lawns = suitable habitat for ground-nesting bees 3. White clover is better suited in bee conservation lawns. 14

15 Conserve Pollinators and Natural Enemies Diversity of flowering plants that provide overlapping, season long bloom and alternate prey (food) Nesting and egg laying sites Shelter without disturbance for overwintering Provide undisturbed nesting sites for your native bees mason bees nest in galleries in wood or hollow tubes and plant stems Photograph by USDA-ARS Photos by S. Bambara, NCSU Slide courtesy of P. Shrewsbury, UMD Provide undisturbed nesting sites for your native bees mason bees nest in galleries in wood or hollow tubes and plant stems Provide undisturbed nesting sites for your native bees thin areas in lawn for plasterer and halictid bees Video by P.M. Shrewsbury, UMD From: Slide courtesy of P. Shrewsbury, UMD Slide courtesy of P. Shrewsbury, UMD 15

16 Provide undisturbed nesting sites for your native bees: leave empty rodent holes and rotting wood Gary Budnick, bugguide.net Dr. Rebeccah Waterworth Questions? Gary Budnick, bugguide.net 16