Biocontrol of thrips: From roadblock to cornerstone Rose Buitenhuis Maryland Greenhouse Growers Association Aug 6, 2014
From roadblock... Western flower thrips became an invasive species in the 80 Thigmotactic behaviour, eggs in leaf tissue Haplodiploid, high fecundity - rapid population increase and strong selection Wide host range good detoxification mechanisms Many chemicals used to control thrips Rapid development of resistance Incompatible with biocontrol
... to cornerstone Loss of effective chemicals Research effort on biocontrol of thrips Estimated 90% of biocontrol budget spent on thrips Need to control other pests without nuking thrips biocontrol
Use of biocontrol in Ontario greenhouse floriculture Don't use bios Start to finish Beginning only Only at certain times of the growing season Based on: 2014 survey of ornamental growers (97 responses)
Most problematic pests Crop Pest 1 Pest 2 Mums Thrips Spider mites Annuals* Thrips Aphids Poinsettia Whitefly * Bedding plants, baskets, other annuals Recurring themes : Affordability, cost Decrease lag time from treatment to effect Improved application techniques, automation Better bios for aphids
Chrysanthemum IPM RIGHT CONTROL AGENTS Effective Pest control RIGHT PLANT RIGHT ENVIRONMENT Plant resistance Genetic Induced Production practices Fertilizer
Plant factors plant breeding Kos et al., 2014. Entomologia Experimentalis et Applicata 151: 198-208
Plant factors induced resistance Pineda et al., 2010. Trends in Plant Science 15: 507-514
Plant factors crop management 33% Reducing fertilizer can reduce pest abundance. Chow et al., 2012. Journal of Applied Entomology 136: 520-529
Chrysanthemum IPM RIGHT CONTROL AGENTS Effective Pest control RIGHT PLANT Plant resistance Genetic Induced Production practices Fertilizer RIGHT ENVIRONMENT Exclusion/sanitation Clean start Mass trapping
Environmental factors physical control Exclusion Sanitation / clean up post harvest
Environmental factors - clean start How do pests get in the crop? Fly/crawl in from outside On introduced plant material - Cosmopolitan pests - Insecticide resistant insect strains
Environmental factors - clean start Thrips will arrive on cuttings To start clean cuttings immersed in: Low toxicity, contact insecticides Insecticidal soap* Horticultural oil* Suffoil BotaniGard* *W. Romero, University of Guelph, 2011 Slide courtesy Wendy Romero
Environmental factors physical control Sampson & Kirk, 2013. PLoS ONE 8: e80787 Buitenhuis & Shipp, 2006. Environmental Entomology 35: 1411-1416
Chrysanthemum IPM RIGHT CONTROL AGENTS Nematodes and fungi Use of predatory mites Orius banker plants Effective Pest control RIGHT PLANT Plant resistance Genetic Induced Production practices Fertilizer RIGHT ENVIRONMENT Exclusion/sanitation Clean start Mass trapping
Control agents Integrated use of BCAs from propagation to finishing to shipping
Think PREVENTATIVE Cuttings Assume they will arrive with thrips Start program straight away Thrips a threat throughout Finishing Other pests will arrive Aphids, leaf miner, mites Early intervention
Thrips control: Misting to finishing Misting Weekly BotaniGard sprays (3x) S. feltiae weekly N. cucumeris broadcast weekly (3x) Finishing N. cucumeris mini-sachets S. feltiae weekly
number of nematodes/g dry media Nematodes 200 180 160 140 120 100 80 60 40 Media only Media + Plant Media + Steinernema Media + Plant + Steinernema 20 0 0 2 4 6 8
Mean no. thrips/4 plants Met 52 plus S. feltiae 50 45 40 35 2 weeks 4 weeks 8 weeks 30 25 20 15 10 5 0 Control Met 52 High Met 52 Low S. feltiae Combo
Number of N. cucumeris Predatory mite sachets 1400.0 1200.0 1000.0 800.0 600.0 400.0 200.0 0.0 1 2 3 4 5 6 Weeks after release
Sachet placement Mean temp ( C) Mean relative humidity (%) 40.0 35.0 Plant sachet Sticky card 90.0 80.0 Plant sachet Sticky card sachet 30.0 70.0 25.0 60.0 20.0 50.0 15.0 Date 40.0 Date
No. of Cucumeris Sachet placement 120 Company A Plant sachet In situ sachet Sticky card sachet 500 Company B 100 400 80 60 300 40 200 20 100 0 W1 W2 W3 0 W1 W2 W3 Weeks after release Weeks after release!! Place sachets in shade, protected from the sun!!
Dispersal
Dispersal It is important to ensure good coverage of the crop when using predatory mites like A. swirskii. Having plants touching or providing bridges will promote dispersal.
Dispersal
Swirskii vs. cucumeris? Laura Hewitt,MSc
Banker plants Provide a food source and/or an alternative reproduction site for natural enemies Ensure a constant presence of natural enemies in the crop
Examples of banker plants in commercial greenhouse production Pest Banker plant Food source Natural enemy Aphids Oat, wheat Rhopalosiphon padi Aphidius colemani Thrips Castor bean Pollen Iphesius degenerans Whitefly Mullen Plant sap Dicyphus hesperus Thrips Ornamental peppers Pollen Orius insidiosus Amblyseius swirskii
Orius banker plants Meghann Waite, MSc
Oviposition and hatching Development time Nymphal survival Population increase Orius banker plants Black Pearl pepper = = = = Purple Flash pepper = = = + Gerbera = + = = Marigold = = - - Feverfew = = = = Castor bean = = - = Sunflower - - -
Mean number of Orius Mean number of thrips Mean Number of Orius Mean Number of flowers Orius banker plants greenhouse studies 7 6 5 4 3 2 1 0 Orius Flowers 28-Feb 31-Mar 30-Apr 31-May 30-Jun 50 40 30 20 10 0 2.5 2 1.5 1 0.5 Orius Thrips 2.5 2 1.5 1 0.5 0 28-Feb 31-Mar 30-Apr 31-May 30-Jun 0
Orius/plant Orius/plant Orius banker plants important factors 16 14 12 10 8 6 Vegetative Flowering Vegetative + eggs Flowering + eggs 10 8 6 4 Warm greenhouse Cool greenhouse 4 2 2 0 Jul. 21 Aug. 4 Aug. 18 Sept. 1 Sept. 15 0 March 28April 11April 24 May 9 May 23 June 6 June 20
Other pests Other pests will arrive Other thrips: onion thrips, echinothrips Aphids, leaf miner, mites Early intervention is key Integration with thrips biocontrol
Pesticide considerations Broad spectrum pesticide Selective pesticide Generalist 1 Generalist 2 Specialist 1 Specialist 2 Pesticide resistance growing issue for all pests Pest 1 Pest 2 Pest 3 Crop
Systems approach Strategic selection of Right biocontrol agents (combined with innovative tools that increase their effectiveness) Right environment (clean start) RIGHT CONTROL AGENTS Right plants (lots of potential for breeding and induced resistance) Most effective and economic solution Effective Pest control RIGHT PLANT RIGHT ENVIRONMENT
Avoid tunnel vision
Think outside the box Art vs science?
Michael Brownbridge Angela Brommit Taro Saito Paul Côté Graeme Murphy (OMAFRA) Cynthia Scott-Dupree (University of Guelph) Les Shipp (AAFC)