Greenhouse Insect Biology and Management Jen White & Ric Bessin Dept. Entomology University of Kentucky

Pest management in greenhouses

Why are pests attracted to greenhouses? Lots of food Great climate No enemies

Outline Introduction to Integrated Pest Management Biology of common greenhouse pests Chemical controls Next time: Biological and Alternative controls

Integrated Pest Management Integration of tactics – Biological – Chemical – Cultural – Physical/mechanical More reliable control Goal: Mitigate pest damage while protecting human health, the environment and economic viability

Components of an IPM Program Pest prevention Pest identification Monitoring and population assessment Control action guidelines Integration of tactics – Biological – Chemical – Cultural – Physical/mechanical

Prevention Keep them out! Inspect incoming stock – Isolation Mechanical exclusion Weed removal – Inside and outside GH – No extra flowering ornamentals Prevent year-to-year carryover – Remove residues – Sanitize

Pest Identification Why is it important? – Misidentification can contribute to failure – Incorrect biological or chemical controls

Common Greenhouse Pests Mites Thrips Whiteflies Aphids Fungus gnats Shore flies Mealybugs Others… Characteristics – Small – Hidden – Short life cycle – Numbers build fast

Fungus gnat Mealybug Whitefly Aphid Mite Shore fly Thrips Relative Sizes

Common Greenhouse Pests Mites Thrips Aphids Whiteflies Mealybugs Fungus gnats Shore flies Others…

Tiny Webbing Mite identification

Tiny Webbing Eight legs, no wings – NOT insects Two spots – Two spotted spider mite Other species – Lewis, Broad, Cyclamen Mite identification

Spider Mites Attack species of plants Life cycle in 8+ days Females lay 100+ eggs Sap feeders Under leaves, around buds Prefer tender leaves Two-spotted spider mite

Mites: Monitoring Scouting – look for stippling, mottled leaves – webbing – premature leaf drop Examine under leaves

Mites: Management Cultural – Reduce plant stress – Spritz with water

Common Greenhouse Pests Mites Thrips Aphids Whiteflies Mealybugs Fungus gnats Shore flies Others…

Thrips Identification Tiny Yellow-ish Linear Most common: Western flower thrips

Thrips Damage Deformed leaves Decaying flowers Silvery, flecked scars Black fecal spots

Thrips Biology  Pierce plant cells  Young growth and flowers  Tightly furled  Mainly females  150 to 300 eggs  Life cycle: 12+ days  Vector tospoviruses  Impatiens necrotic spot virus (INSV)  Tomato spotted wilt virus (TSWV) Western flower thrips

In soil In plant

Thrips: Monitoring  Early detection  Blue or yellow cards  Minimum of 3  Placed near doors/vents thrips sensitive plants  1 per 2000 ft 2 minimum  Placed just above canopy  Can do a subset of grids  New cards periodically  Tap method  Same person, regular basis (weekly)

Thrips: Management  Cultural Control  Remove weeds (that may harbor viruses)  Crop alternation  Petunia as virus indicator plant  Sensitive to virus  Not systemic  Use vegetative plants  Blue plastic plate to attract Western flower thrips “Summer madness” “Cascade blue”

Common Greenhouse Pests Mites Thrips Aphids Whiteflies Mealybugs Fungus gnats Shore flies Others… Melon or cotton aphid

Aphid identification  Pear shaped body  Cornicles = “tailpipes”  Most common species Melon or cotton aphid Potato aphid Joseph Berger Green peach aphid Whitney Cranshaw >135 plant families >90 plant families >125 plant families

Aphid Biology  High reproductive rate – 100 live young/female – Asexual – Live birth – Life cycle 7-10 days  Remove sap  Produce honeydew

Aphid Damage Stunt plants Curling, cupping of leaves Sticky honeydew – Sooty mold Transmit viruses

Aphids: Monitoring Scouting  Insects on stems, fresh growth, under leaves  Sticky honeydew on leaf surface Yellow cards: caution! Most aphids don’t have wings!

Aphid Management Avoid excess Nitrogen Whitney Cranshaw

Common Greenhouse Pests Mites Thrips Aphids Whiteflies Mealybugs Fungus gnats Shore flies Others…

Whitefly Identification Greenhouse Trialeurodes vaporariorum Sweet potato or Silver leaf Bemisia tabaci Photo credit: Gaucho Ronald Smith UGA Banded winged Trialeurodes abutiloneus

Whitefly Identification Greenhouse Trialeurodes vaporariorum Sweet potato or Silver leaf Bemisia tabaci

Whitefly Biology  All stages under leaf  Sedentary immatures  Life cycle in 1 month  Highly visible  MANY host plants Greenhouse whitefly

Whitefly Damage  Yellowing and discoloration  Stunt plants  Honeydew and mold  Virus transmission

Whiteflies: Monitoring – yellow cards – plant inspection Undersides of leaves Honeydew Sooty mold Shake plant for adults Sweet Potato Whitefly

Whiteflies: Management  Cultural control  Plant-free periods  Time depends on temperature ->cooler temps, keep plant-free longer

Common Greenhouse Pests Mites Thrips Aphids Whiteflies Mealybugs Fungus gnats Shore flies Others…

Mealybugs  “Big”: ¼ inch  Waxy, cottony, fringed  Sucking insects – produce honeydew – stunt plants  Attack all parts of plant  Life cycle: 1 month  Reduce marketability

Mealybugs: Monitoring  Scouting  White flecks on midribs, leaf axils, leaf underside  Honeydew and sooty mold

Common Greenhouse Pests Mites Thrips Aphids Whiteflies Mealybugs Fungus gnats Shore flies Others…

Fungus Gnats  Small, delicate flies  Feed on root, stems, decaying debris  Need damp media  Life cycle 1 month  May promote diseases – Pythium, Verticillium, Botrytis  Watch pet (wet) plants !

Fungus Gnats: Monitoring  Yellow cards  Horizontal orientation  Potato disks

Fungus Gnats: Management  Cultural control  Less water!  Remove standing water  Sterilize/contain compost

Common Greenhouse Pests Mites Thrips Aphids Whiteflies Mealybugs Fungus gnats Shore flies Others…

Shore Flies Small, robust flies Feed on algae Must have damp media Leave frass on plants May move Pythium spores

Shore Flies: Management Cultural Control – Eliminate algae

Build an IPM Monitoring Program Start simple Careful inspection Scout at least once per week Designate pest management units (PMU) Have some prior knowledge of problems Keep good written records (database)

Thresholds Why use them? – Help maintain pesticide efficacy – Reduce disruption of cultural practices – Minimize phytotoxicity – Increase profit How to establish thresholds – From research – Systematic monitoring, historic records – Experiment

Greenhouse Insecticides/Miticides Food crops vs. ornamentals Read labels carefully Must have crop on label and no greenhouse restrictions Crop safety (new plant types/chemicals) Prefer selective materials – More compatible with biocontrol

Active Ingredients pyriproyfen:Distance/Distance spiromesofen:Judo/Oberon spirotetramat: Kontos/Movento pyridaben:Sanmite/Nexter acetamiprid:Tristar/Assail thiamthoxam:Flagship/Platinum abbamectin:Avid/AgriMek pymethozine: Endeavour/Fulfill dinotefuran:Safari/Venom imidacloprid:Marathon II/Admire Ornamental formulation/ Vegetable formulation

Ornamental Products with Vegetable Uses Tristar (acetamiprid): Some transplants Kontos (spirotetramat): Some transplants Distance (pyriproxyfen): Tomatoes Talus (buprofezin): Tomatoes Pylon (chlofenapyr): Fruiting vegetables Floramite (bifenazate): Tomatoes Tetrasan (etoxazole): Tomatoes

Vegetable insecticides/miticides Without GH restriction Sevin Malathion Orthene Mustang max Pounce Baythroid Asana XL Proaxis Danitol Warrior Without GH restriction Admire Belay Venom Distance/Knack Fulfill Dipel Courier Agri-Mek Acramite These can be used in the greenhouse so long as the crop is on the label

Prohibited Vegetable Insecticides With GH prohibition Diazinon Endosulfan Assail Platinum/Actara Radiant Proclaim Beleaf Rimon Intrepid With GH prohibition Avaunt Oberon Movento Coragen Portal Belt/Synapse

Systemics for Ornamentals ProductSystemicTarget pestsIRAC Class Marathon II Yes ( ↑) Aphids, WF, soft scale, fungus gnats, leafminers4A Flagship 25WG Yes ( ↑) Aphids, WF, fungus gnats, leafminers4A Safari 20 SG Yes ( ↑) WF, mealybugs, aphids, soft scale, fungus gnats, leafminers, armored scale 4A Kontos Yes( ↑↓) WF, mealybugs, aphids, soft scale, leafhoppers, scale crawlers (vegetable transplants: Fruiting and leafy) 23 Tristar 30 SGNoWF, mealybugs, aphids, leafhoppers, thrips, leafminers, scale (Vegetable transplants: Fruiting, leafy, cucurbit, cole, and bulb) 4A

IGR Foliar Sprays for Ornamentals ProductTypeTarget pestsIRAC Class Distance 0.86ECIGRWF, scale, fungus gnats, shoreflies (Greenhouse tomatoes (>1”), bell pepper, eggplant) 7D Talus 40 SCIGRWF, mealybug, leafhoppers, scale crawlers (Greenhouse tomatoes) 16 Pedestal 0.83ECIGRWF, thrips, caterpillars, leafminers15 Ornazin 3% ECIGRWF supression, many other pest groups (brassica crops, cucurbits, eggplants, herbs and spices, legumes, peppers, tomatoes, and other miscellaneous crops grown in greenhouses) UN

Foliar Sprays for Ornamentals ProductAIPests targetedIRAC class Aria 50SGflonicamid Aphids, WF, leafhoppers, mealybugs, scale stink bugs 9C Conserve 1SCspinosad Caterpillars, thrips, leafminers 5 Decathlon 20 WPcyfluthrin Thrips, beetles, caterpillars * 3A* TalstarOne 0.67 ECbifenthrin Thrips, beetles, caterpillars, plant bug, broad mites * 3A* Tame 2.4ECfenpropathrin Thrips, beetles, caterpillars, plant bugs* 3A* Hachi-Hachitolfenpyrad Thrips, aphids, scale, leafhoppers, whitefly, caterpillars 21A Pylonchlofenapyr Spider mites, broad mite, rust mites, cyclamen mite, beet armyworm, loopers, thrips, caterpillars (greenhouse fruiting vegetables 0-PHI) 13 Endeavor 50 WDGpymetrozine WF, aphids 9B Mavrik AquaflowTau-fluvalinate Aphids, WF, mites, thrips, caterpillars 3A* Mesurol 75Wmethiocarb Thrips, slugs, snails 1A

Miticides for Ornamentals ProductAIMites/Pests targetedIRAC Class Akari 5SCfenpyroximate Spider mites, broad mites, cyclamen mites, rust mites, WF, mealybugs 21A Judo 4SCspiromesifen Spider mites, broad mites, cyclamen mites, rust mites, WF 23 Avid 0.15ECabamectin Spider mites, broad mites, cyclamen mites, rust mites, WF, aphids, thrips, leafminers 6 Floramite 2 SCbifenazate Spider mites (greenhouse tomatoes) UN Shuttle OAcequinocyl Spider mites 20B Tetrasan 5 WDGEtoxazole Spider mites (greenhouse tomatoes) 10B UltiflorMilbamectin Spider mites 6 Pylonchlofenapyr Spider mites, broad mites, cyclamen mites, rust mites 13 OvationClofentezine Spider mites 10A Sanmitepyridaben Spider mites, broad mite, WF 21A HexygonHexythiazox Spider mites 10A

Ornamental Insects - Chemigation Products that allow for some chemigation uses – Marathon II – Flagship – Safari – Kontos – Conserve – Ornazin -- Sevin -- malathion -- Mustang Max -- Pounce -- Baythroid -- Asana XL -- Proaxis -- Warrior -- Admire -- Venom -- Dipel

Resistance Management Only treat if needed Rotate to a different IRAC class with each pest generation Do not tank mix products in the same chemical class Utilize biological control