Master Gardener’s module –insects part I Insect basics and pests Carmen Greenwood Insects – a little review of the basics & some pests Body regions 1 • Development types 2 • How insects are organized and classified 3 • A few important groups that contain both pests and beneficials • How mouthpart structure is related to insect damage Soil and leaf litter Ametabolous dwellers Aquatic orders predatory orders Hemimetabolous herbivorous orders Parasitic orders Holometabolous The 4 largest groups of insects are those intimately associated with plants, either through plant‐feeding or pollination Phytophagy Categories of phytophagy (herbivorous feeding strategies): • Leaf chewing • Sap sucking • Seed predation • Gall induction • Mining living tissues of plants How many different ways can you eat a plant? • Orthoptera = “straight wing” 6 Orders important to those of us (20,000+) who deal in plants (#species) • Grasshoppers, katydids, crickets • Hemiptera = “half wing” (35,000) • True bugs • Coleoptera = “sheath‐wing” (350,000) • Beetles • Lepidoptera = “scale wing” (150,000) • Butterflies, moths • Hymenoptera = “membrane wing” (115,000) • Bees, ants, wasps • Diptera = “ 2 wing” (150,000+) • Flies Class Insect divided into orders based on structural differences 1. Type of metamorphosis 2. Type of mouthparts 3. Wings – number and characteristics 4. Other characteristics Two kinds of development ‐ Gradual metamorphosis • Gradual metamorphosis • Hemimetabolous development • Immatures are “miniature” versions of adult • Immatures and adults often occupy the same niche • Wings develop between last instar and adulthood Two kinds of development ‐ Complete metamorphosis Holometabolous insects • Adults and immatures may occupy completely different niches • Adults and immatures look different • Have different mouthparts • Often feed on different things • Egg ‐ Larva – pupa ‐ adult Orthopterans cerci tegmina • 3 life stages: egg, nymph, adult • Many nymphal instars Orthopterans • Adult stage has wings and is sexually mature • Leaf chewing mouthparts Leaf chewing • Lepidoptera, Coleoptera, Orthoptera, Phasmatidae and some Hymenoptera • Induced defenses: sometimes plants subject to herbivory will respond chemically Butterflies/moths (larvae), Beetles, Grasshoppers/crickets, Walking sticks and Sawfly larvae Hemiptera: True Bugs Half‐winged • Metamorphosis • Mouthparts • Four wings • forewings hemelytra • hind wings • Triangular plate = scutellum Piercing‐sucking mouthpart which enables them to feed on phloem, xylem or prey Hemelytra True Bugs • Gradual metamorphosis • Hemimetabolous development • Immatures are “miniature” versions of adult • Immatures and adults often occupy the same niche • Wings develop between last instar and adulthood Hemiptera “true bugs” Hemelytra (half‐wing) • 3 suborders • Heteroptera – the True bugs • Auchenorrhyncha – hoppers (leaf hoppers, tree hoppers, frog hoppers, cicadas • Sternorrhyncha – aphids, scales adelgids, whiteflies Sap‐sucking • Mostly Hemiptera and Thysanoptera • Leads to wilting, stunting or distortion in plant growth • Transmission of plant viruses is the most serious problem • Excretions of phloem‐feeding hemiptera can promote black sooty mold growth Hemiptera: Suborder Heteroptera (the “true bugs”) • Most hemipterans are pests True Bugs • Suck on plant vascular fluids and transmit disease • Some are important predators of pests, like this assassin bug Herbivorous Hemipteran families: 1. Berytidae (stilt bugs) 2. Coreidae (squash bugs and leafooted bugs) 3. Rhopalidae (scentless plant bugs) –Boxelder bug 4. Miridae (plant bugs)‐ Lygus bugs 5. Lygaeidae (Seed bugs) ‐ Hairy Chinch Bug 6. Tingidae (lace bugs) 5 6 4 1 2 3 Brown marmorated stink bug • Halyomorpha halys (Hemiptera: Pentatomidae) • Native to China, Japan, Korea, Taiwan • Polyphagous insect that feeds on many different plants; fruit, soybeans, vegetables…. • A specialist egg parasitoid, Trissolcus japonicus (Hymenoptera: Platygastridae), imported from Beijing, China • Collected in PA in 1998 but probably arrived earlier Range (2017) and risk • At least 12 North American species of stink bug egg parasitoids in at least three families Management options (Encyrtidae, Eupelmidae, Platygastridae) parasitize sentinel (laboratory‐sourced) BMSB egg masses deployed in the field • Sink bugs are also subject to predation by ground beetles, spiders and wasps • While insecticide recommendations vary according to availability on different crops, Actara, Brigade, Danitol, Mustang Maxx, and Lannate have shown good efficacy in trials Trissolocus japonicus the “Samurai wasp” can parasitize up to 90% of the eggs. In 2014 Don Weber discovered it had arrived in MD, VA Predatory Hemipteran families: •Reduviidae (assassin bugs) •Phymatidae (ambush bugs) •Nabidae (damsel bugs) •Anthocoridae (minute pirate bugs). The major families of aquatic predators include: •Corixidae (water boatmen) •Gerridae (water striders) •Nepidae (water scorpions) •Belostomatidae (giant water bugs) •Naucoridae (creeping water bugs). Hemiptera includes 2 other groups (suborders) of very small plant‐sucking insects • These also have sucking mouthparts but the scutellum and hemelytra are not necessarily present • Some of these are serious pests • Auchenorrhyncha “hoppers” • Sternorrhyncha “aphids, scales, whiteflies, psyllids” Leafhoppers, Treehoppers, Planthoppers, Froghoppers • Lycorma delicatula (Hemiptera: Fulgoridae) • Spotted in Delaware Co., NY Nov, 2017 Spotted lanternfly • Potential threat to grapes, apples, hops and forest products • First found in Bern Co. PA 2014 • Native to Asia • Insecticide applications – check with Cornell extension for current Management options recommendations • Remove egg masses when visible cicada Little soft things – capable of BIG impacts Hemlock Wooly Adelgid – Adelges tsugae Coleoptera –The Beetles From left to right: Curculionidae (weevils) Carabidae (ground beetles) Chrysomelidae (leaf chewing beetles) Scarabaeidae (scarabs) Beetle wings Taking off! Forewings = for protection Hind wings = for flight Because they tend to be specialized feeders many species are used as biological control agents of invasive weeds Because they tend to be specialized feeders many species are used as biological control agents of invasive weeds Lepidoptera Scale‐winged Butterflies & Moths • Complete Metamorphosis • Siphoning Mouthparts • Four wings • Forewings • Hind wings Egg Complete Lepidoptera Larva Pupa Adult • Butterflies vs. moths Lepidoptera • Diurnal vs nocturnal • Intimately associated with plants in both adult and immature stage Scale‐wings Hymenoptera ‐ Bees, wasps, ants Egg Larva Complete: Hymenoptera Adult Pupa Hymenoptera • Most are parasitoid wasps –important beneficials that kill pests • Native pollinators (wild bees) • Domestic pollinators (honybees) • Sawflies –larval forms are foliage‐feeding caterpillars Trichogramma sp. On Arctiid egg The Flies Flies Halteres • Evolved independently in 4 different orders; Diptera, Lepidoptera, Coleoptera and Hymenoptera (larval flies and moths predominant…eg. Agromyzidae) Leaf mining • Some insects also mine stems, trunks, roots and fruits • Economic damage in fruits and roots; overall plant productivity in leaves Damage from Liriomyza munda “vegetable leaf miner” Spotted wing drosophila ‐ SWD • Drosophila suzukii (Diptera: Drosophilidae) • Observed in NY in 2011 • Small fruit crops most at risk • Most are nectar feeders Blood feeding flies • Females take blood meals when conditions are good for oviposition Culicoides spp. Wide range of hemorrhagic diseases in domestic Culicidae ‐ mosquitoes and wild animals Sand flies (Leishmaniasis; human and canine) Tabanidae – Horse flies and Mosquito larvae emerging from egg raft deer flies Hippoboscidae Glossinidae - Tse tse flies (Trypanosomiasis in humans (i.e. sleeping sickness) in other Muscidae ‐ Stable flies animals (nagana) Be careful with common names • Two words means it is in that order • House fly • Lady beetle • Stink bug • One word means it is in a different order • Ladybug • Junebug • Dragonfly • Butterfly • Firefly • Lightningbug Be wary of common names • Butterfly • Ladybug • Firefly • Horn fly • Stable fly • Long‐horned beetle • Junebug • Whitefly • Boxelder bug • Louse fly Soil and leaf litter Ametabolous dwellers Aquatic orders predatory orders Hemimetabolous herbivorous orders Parasitic orders Holometabolous.