Greenhouse Pest Management. Greenhouse Functions. Key production target dates (IN) Display. Production

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1 Greenhouse Pest Management Greenhouse Functions Display Conservatory Box store retail sales Production Retail Wholesale/retail Export Key production target dates (IN) Easter Lilies (April) Annuals, Perennials and Bedding plants Mother s day (May) Home gardeners (April-June) Commercial landscape (April-June) Chrysanthemums (August-Sept) Poinsettia (Nov-Dec) House plants (year-round) 1

2 Greenhouse IPM Monitor Sticky cards (flying insects) Visual inspection (immatures and wingless) Record Keeping Where are pests building or coming from? Make maps to locate sources Decision making Effective use of cultural tactics, pesticides and biological control Evaluation Are pests likely to be a problem at time of sale? Specialized greenhouse pest management issues Safe reserve for tropical pests and beneficials Movement of pests by fans Movement of pests on yellow clothes Sanitation Weeds and Pet plants as pest reservoir Bag old plants in greenhouse as you discard to prevent pest movement Pesticide resistance Need to rotate pesticide by mode of action every life cycle Physical exclusion Quarantine / inspection of new plants Screening of vents and fans Pesticide delivery systems Dusts (potential visible residue) Wettable Powders, Water Soluble Packets, Dry Flowables, Flowables Emulsifiable Concentrates (potential phyto) Granular, Baits (slow and expensive to apply) Products applied to ghouse that must be safely vented Aerosols (Total release cans) Fogs (heated metal pans) Smokes (light and go) Fumigants (release as gas) 2

3 Worker Protection Safety Workers- People who work in greenhouses, or handle or water plants Pesticide Handler- People who apply or mix or monitor pesticide treated area Workers must wear personal protective equipment (PPE) when entering a treated area during the restricted entry interval (REI) Potential for biological control in greenhouse Closed system sets the stage for sustainable biological control. Inoculative releases- Seed crop with beneficials that provide control Inundation releases- Regular addition of beneficials to keep pest population low Links to Greenhouse Biocontrol New England Greenhouse Pest Management Guide Links to information about useful beneficial insects al_control.html Link to site on pesticide side effects on beneficials 3

4 Greenhouse pests Thrips Whiteflies Fungus gnats Shore flies Spider mites Leaf miners Aphids Mealybugs Bulb mites Thrips Feathery wings Adults winged Nymphs wingless Rasping mouthparts Many are omnivores Western Flower Thrips Direct damage to flowers when adults and immatures feed Vectors impatiens necrotic spot virus Many host plants 4

5 Flower Distortion by WFT on Chrysanthemum damaged healthy Damaged blooms Impatiens Necrotic Spot Virus Western Flower Thrips Monitor winged adults using yellow sticky cards Look for wingless immatures in flowers and other tight spaces 5

6 WFT Life cycle Above ground mobile stages can be killed by pesticides and predaceous mites (Amblysieus, Neoseiulus) Below ground stage can t be killed by pesticides, but may be killed by predaceous mites (Hypoaspis spp) WFT Control Screen vents Eliminate reservoir plants (weeds, old plants etc.) Monitor with sticky traps-tends not to be a problem in winter months If applying contact pesticide, do so at 5 day intervals to kill adults emerging from pupae htm Thrips Pesticide Considerations Pesticide Resistance Rotate classes of 3 weeks Thigmotaxis Thrips are omnivores. They hide in buds, coverage is difficult. Floral protection Systemics like imidacloprid do not translocate to flowers. More mobile products are likely in future. Compatible with BC Spinosad won t kill mite predators, is a lamellar systemic 6

7 Biological Control for WFT Mites ement/thripsbio.html Amblysieus cucumeris and degenerans (Foliar predators) Hypoaspis miles and aculeifer (soil dwelling pupal predators) Plant bugs Orius spp. Fungal disease Beauvaria bassiana Greenhouse thrips Adults are black. Yellow nymphs produce black fecal drops. Not a disease vector Other Greenhouse Thrips Gladiolus thrips A problem for gladiolus growers Tobacco thrips Migrate into ghouse late in season, can be confused with gladiolus thrips See key for other thrips 7

8 Whiteflies Produce honeydew and cause sooty mold problem Flying white adults can be unsightly Problem on Poinsettias and may other crops Can vector diseases in some instances Whitefly Life Cycle Adult is the mobile phase Eggs,nymphs and pupae transported on plants. (Courtesy University of GA) Greenhouse Whitefly 8

9 Adult Greenhouse Whitefly Adult Silver Leaf Whitefly Silver Leaf Whitefly Nymphs 9

10 Silverleaf vs GHS Whitefly silverleaf greenhouse Bandedwinged Whiteflies Similar to greenhouse whitefly, but adult has banded wings Whitefly management Inspection of new plant material Sanitation Monitor plants and yellow sticky cards Biological Controls: Encarsia formosa (Inoculative) Eretmocera eremicus (Inundative) ent/biological_control.html 10

11 Poinsettia -Whitefly Innundative release (after Van Driesche 2002) Eretmocerus eremicus released weekly for 15 weeks. Insect growth regulator (Fenoxycarb) applied at week 7 and 8 to slow whitefly population growth Cost of $.25/plant competitive with imidacloprid (plus follow up sprays) Encarsia formosa Release Cards Greenhouse Whitefly (black = parasitized) 11

12 Chemical Control of Whiteflies Whitefly Control in Greenhouses and Interior Plantscapes: University of Georgia Imidacloprid gives long lasting control but must use other materials to prevent resistance Many pesticide options exist 12