Identification and Management of Vegetable Garden Insect Pests
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Identification and Management of Vegetable Garden Insect Pests Kevin Burls, Ph.D. Integrated Pest Management Educator University of Nevada, Reno Extension Grant funding Grow Your Own, Nevada 2020 provided by Photo: Cynthia Scholl Outline • Basics of Integrated Pest Management (IPM) • Insect pest identification • IPM techniques and examples • A few examples of integrated pest programs for common pests What is a pest? • Too many in one place • Takes resources from/ cause injury to production plants • Appears where you don’t want it • Unsightly Green peach aphid (Myzus persicae) giving live birth to a nymph. Photo Credit: Jim Baker, North Carolina State University, Bugwood.org How do things become pests? • Unhealthy plants or soil • Stressful environment • Seasonality • Annual cycles • Lack of predators or competition Macrosiphum rosae, rose aphid. Photo by Anne W. Gideon, Bugwood.org Integrated Pest Management (IPM) • Integrated Pest Management • Management designed to reduce pests below economic thresholds in ways that minimize non-target effects • Some quick keys to pest management • Identify the pest first • Monitor regularly • An ounce of prevention for a pound of cure • Measure responses to treatment Why think about IPM? • Reduce chemical pesticide use • React to changing conditions • Reduce nontarget environmental effects • Cost and time savings • Protect native or vulnerable species Why use IPM as a pest management framework? • Provides an algorithm for control tactics • Facilitates the measuring of success or failure • Control or prevention of multiple pests at once • Best Practices for responsible pesticide use IPM Basics • Identification • Monitoring & action thresholds • Economic • Aesthetic • Health and Safety • A hierarchy of techniques • Documenting and revising Pitfalls of misidentification Pitfalls of misidentification By Judy Gallagher - https://www.flickr.com/photos/52450054@N04/8061 CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=55253277 Photo: Whitney Cranshaw, Colorado State University, Bugwood.org Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org Major groups of garden invertebrate pests • True bugs • Aphids, stink bugs, and relatives • Moths & butterflies • Caterpillars • Earwigs • Grasshoppers, crickets and katydids • Beetles • Elm beetles, longhorn beetles, weevils, and relatives • Flies • Fungus gnats • Thrips • Spider mites Photo: Cynthia Scholl A few things we won’t be covering • Wasps • Ants • Spiders • Most flies My favorite arthropod identification books General gardening and pollinators • Attracting Native Pollinators, Xerces Society, 2011 • Farming with Native Beneficial Insects, Xerces Society, 2014 General insect identification • Kaufman Field Guide to Insects of North America, Eric Eaton & Ken Kaufman, 2007 • National Wildlife Federation Field Guide to Insects and Spiders of North America, Arthur V. Evans, 2008 • www.bugguide.net or www.whatsthatbug.com Bee identification • Bee Basics: An Introduction to Our Native Bees, Beatriz Moisset & Stephen Buchmann, available for download at: http://www.pollinator.org/PDFs/BeeBasicsBook.pdf • California Natural History Field Guide to the Common Bees of California, Gretchen Lebuhn, 2013 • The Bees in Your Backyard, Joseph Wilson and Olivia Messinger Carril, 2015 Insect Anatomy Head Thorax Abdomen Wings on thorax 3 pairs of legs Important areas to study to identify common insect orders Head Thorax Abdomen 3 pairs of legs Insect identification Taxonomy: The field of naming and Common pitfalls to classifying organisms into groups insect identification Example: Monarch butterfly • Missing the type of bug: mistaking a fly for a bee, a true bug for a beetle Kingdom= Animalia Phylum= Arthropoda • Believing a quick Google search: Class= Insecta Many times your search terms will Order=Lepidoptera bring up the most common invasive Family= Nymphalidae instead of the native Genus= Danaus • Trying too hard: Insects are very Species= plexippus diverse, and becoming good at identifying anything takes time! This level distinguishes many major groupings- beetles, flies, dragonflies and damselflies, etc. Mimicry (Or: These bugs all look the same!) Mimicry is the semblance to two or more different species to each other in a way that confers an evolutionary advantage (e.g. predator protection) for at least one of the species Müllerian mimicry: Two species that are both well protected look like each other Batesian mimicry: One or more unprotected species looks like an honestly well- defended species Large milkweed bugs Boxelder bug bumblebee fly- bee mimic By Photo by Greg Hume (Greg5030) - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curi d=4701104 By Judy Gallagher - https://www.flickr.com/photos/52450054@N04/8061651776/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=55253277 True bugs (Hemiptera) • Defined by a poking and sucking mouthpart that tucks back into a sheath • Aphids, planthoppers, squash bugs, boxelder bugs, whiteflies, scale insects, bed bugs • Assassin bugs, cicadas, water striders • Aphids: identified by pear shaped bodies, long legs and antennae • Adults often identified by V-shape made by closed wings (not present on immatures, or nymphs) • Many species have a somewhat restricted diet so host plant will aid identification Pentatomid bug By Jesse Keith Huffman - Author, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=63069106 By Judy Gallagher - https://www.flickr.com/photos/52450054@N04/8061651776/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=55253277 Aphids Whiteflies Whitney Cranshaw, Colorado State University, Bugwood.org True bug eggs Aphid eggs on rose Squash bug eggs Photo: Whitney Cranshaw, Colorado State University, Bugwood.org By Bdm25 - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=35045808 Moths & butterflies (Lepidoptera) • Adults have scale-covered wings and a flexible straw-like mouthpart • Approximately 10x as many moths as butterflies • Complete metamorphosis: larval life stage is a caterpillar- 6 ‘true legs’ up front, prolegs in back, chewing mouthparts • Moths are sometimes generalists with a broader diet, butterflies are often specialists Tomato hornworm, Manduca quinquemaculata, Cabbage white caterpillar, Pieris rapae one of 121 species of Sphingidae in Nevada Photos: Whitney Cranshaw, Colorado State University, Bugwood.org Fruit tree pests Western tent caterpillar, Apple codling moth, Cydia pomonella Malacosoma californicum By Franco Folini - originally posted to Flickr as Western Tent Caterpillars (Malacosoma Public Domain, https://commons.wikimedia.org/w/index.php?curid=657502 californicum), CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4095034 Geometrid moths • Roughly 1,500 U.S. species; 35,000 species worldwide Digrammia cinereola on Juniper, photo by Nick Pardikes, bugguide.net Earwigs (Dermaptera) European earwig Forficula auricularia • Rear pincers are a good diagnostic • Often most detrimental to young seedlings • Most common species are nonnative • Hated by all who know them Photo: Neil Bertrando Grasshoppers, crickets, and katydids (Orthoptera) • Long, jumping back legs and chewing mouthparts • Often plant generalists • Crickets and katydids have long antennae, grasshoppers have shorter antennae • Locusts of yore no longer a problem • Today we have Mormon crickets Photo: Cynthia Scholl Rocky Mountain locust historic range By C. V. Riley (1877) - The locust plague in the United States: being more particularly a treatise on the Rocky Mountain locust or so-called grasshopper, as it occurs east of the Rocky Mountains, with practical By Jacoby's Art Gallery - http://www.mnopedia.org/multimedia/minnesota- recommendations for its destruction., Public Domain, locusts-1870s, Public Domain, https://commons.wikimedia.org/w/index.php?curid=86723490 https://commons.wikimedia.org/w/index.php?curid=18570553 Katydids Broad winged katydid eggs, Broad winged katydid, Microcentrum rhombifolium Microcentrum rhombifolium Joseph Berger, Whitney Cranshaw, Bugwood.org Colorado State University, Bugwood.org Beetles (Coleoptera) • Distinguished by hard wing covers as adults • Larval forms have six true legs but no prolegs • Enormous variety in lifestyle and feeding Elm leaf beetle, Xanthogaleruca luteola (Chrysomelidae) Whitney Cranshaw, Ward Upham, Kansas State University, Bugwood.org Colorado State University, Bugwood.org Prionus beetle (Prionus sp.) larva (left) and adult (right); each is 4 – 5 in. long Jerry A. Payne, USDA Agricultural Research Service, Bugwood.org By Kaldari - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=69838829 USDA Forest Service – Region 2– Rocky Mountain Region, USDA Forest Service, Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org Bugwood.org Flies (Diptera) • Distinguished by having only one pair of wings, large eyes, short antennae • Large variety of mouthparts and feeding methods • Complete metamorphosis with soil dwelling larvae • Pest status of most flies is related to local environmental conditions- they do not destroy the plants themselves Fungus gnat larvae and adults Photos: Whitney Cranshaw, Colorado State University, Bugwood.org Thrips (Thysanoptera) • Adults are tiny, slender flying insects with fringed wings (no wings on nymphs) • Cut open leaves and digest contents • Biological control requires correct ID • Herbivore and predator lifestyles Alton N. Sparks, Jr., University of Georgia, Bugwood.org Diane Alston, Utah State University,