PEST CONTROL UNDER DIFFERENT LIGHT CONDITIONS Dr. Christine Becker Department of Crop Protection Hochschule Geisenheim University Germany PEST CONTROL UNDER DIFFERENT LIGHT CONDITIONS Dr. Christine Becker Department of Crop Protection Hochschule Geisenheim University Germany PEST CONTROL UNDER DIFFERENT LIGHT CONDITIONS Dr. Christine Becker Department of Crop Protection Hochschule Geisenheim University Germany LIGHT CONDITIONS • What is light? electromagnetic radiation within a certain portion of the electromagnetic spectrum UV-C Near- Infrared 280 Huché-Thélier et al 2016, Environ Exper Bot, modified; Robert A. Rohde, Wikimedia Commons, modified) Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 4 LIGHT CONDITIONS Greenhouse cladding changes the quality and quantity of the transmitted radiation, especially regarding: • intensity (quantity) • UV • NIR • blue wavelengths UV-C Near- Infrared 280 Huché-Thélier et al 2016, Environ Exper Bot, modified Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 5 PEST CONTROL UNDER DIFFERENT LIGHT CONDITIONS Dr. Christine Becker Department of Crop Protection Hochschule Geisenheim University Germany PEST CONTROL • What is a pest? Merriam-Webster dictionary: “a plant or animal detrimental to humans or human concerns (such as agriculture or livestock)“ here: focus on insect pests in agriculture; food competitors to humans Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 7 PEST CONTROL • Feeding on plant sap: aphids Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 8 PEST CONTROL • Feeding on plant sap: aphids Werther Wikipedia, JacopoWikipedia, Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 9 PEST CONTROL • aphids: high taxonomic diversity Many species with diverse shapes, colors and sizes! Arachya Sanjay Eichler Andreas Alvesgaspar Wikipedia Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 10 PEST CONTROL • aphid life cycle, reproduction • Very diverse reproduction cycles! • 1 common model: - beginning of the season: only females, asexual reproduction - declining food quality: winged females produced, to change host plant - end of the season: production of males, sexual reproduction Green apple aphid (Aphis pomi) (Robert Evans Snodgrass, 1930) Yerpo Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 11 PEST CONTROL • aphid morphology antennae 6 legs Green apple aphid (Aphis pomi) (Robert Evans Snodgrass, 1930) stylet in sheath (“rostrum“) cornicles the aphid‘s “behind“ Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 12 PEST CONTROL • aphid feeding Green apple aphid (Aphis pomi) (Robert Evans Snodgrass, 1930) compound eye Front view of wheat aphid, Schizaphis stylet in sheath (“rostrum“) graminum, showing the piercing-sucking mouthparts Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 13 PEST CONTROL • Feeding on plant sap: aphids (Mehrabi 2016, modified) Aphid feeding on phloem sap. st: stylet, scl: sclerenchyma, p: phloem, x: xylem. Scale bar = 1 mm. (“Plants in Action”, Australian Society of Plant Scientists) Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 14 PEST CONTROL • Feeding on plant sap: aphids 2016, modified) 2016, Mehrabi ( effectors in salivar plant defense compounds Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 15 PEST CONTROL • aphids: feeding on plant sap, excreting fluids Arachya Sanjay Cornicles: excretion of defense fluid Amada44 Anus: excretion of honeydew Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 16 PEST CONTROL • also feeding on plant sap: whitefly • weaken plants through salivary toxins • often spread virusus while feeding (like aphids) • excrete honeydew that fosters mold (like aphids) • Prominent pests: - Bemisia tabaci, Silverleaf whitefly - Aleyrodes proletella, Cabbage Whitefly - Trialeurodes vaporariorum, Greenhouse Whitefly gaucho Trialeurodes vaporariorum, Greenhouse Whitefly Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 17 PEST CONTROL • Eating whole leaves: caterpillars, larvae of Lepidoptera (butterflies and moths) Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 18 PEST CONTROL • Eating whole leaves: caterpillars, larvae of Lepidoptera (butterflies and moths) Bright-line brown-eye (Lacanobia oleraceae) Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 19 PEST CONTROL • Eating whole leaves: caterpillars, larvae of Lepidoptera (butterflies and moths) http://www.kreisblatt.de/lokales/main-taunus-kreis/Gespinstmotte-spinnt-einen-Schleier-gegen- Fressfeinde;art676,2990551 Ermine moths, Yponomeutidae family Blend5,6 Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 20 PEST CONTROL • Leaf mining caterpillars: feeding inside the leaf (e.g. Tuta absoluta) http://www.nbair.res.in/insectpests/Tuta-absoluta.php cuticle epidermis https://www.bursadelegume.ro/influenta-atacului-tutei-absolute-asupra-pretului-tomatelor/ palisade mesophyll Leaf miners feed inside the leaf, only leaf mine minor damage to the epidermis. spongy mesophyll They can be a devastating pest, sometimes causing complete yield losses. Double sided leaf mine (Jahrbücher des Nassauischen Vereins für Naturkunde, Band 130, Wiesbaden 2009) Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 21 PEST CONTROL • Caterpillar anatomy • 1: Head • 2: Thorax with true legs (8) • 3: Abdomen with prolegs (6; fleshy, false legs used to cling on, like 10: anal prolegs) • 4: One segment • 5: Horn (not with all species) • 7: Spiracle: opening to respiratory system • 9: Mandibles: jaws for chewing A. M. Liosi/Wikimedia Commons (CC by SA license), modified by Debbie Hadley, WILD Jersey Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 22 PEST CONTROL • Caterpillar anatomy abdomen thorax head prolegs true legs Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 23 PEST CONTROL • Caterpillar anatomy • Mouth parts different from aphids different feeding mode, different kind of damage to the plant • Like aphids: effectors in saliva; signal presence to plant (together with physical AshLin damage to leaves) Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 24 PEST CONTROL • Caterpillars: not all of them are ugly! Ceruna vinula, the Puss Moth Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 25 PEST CONTROL • Caterpillars: not all of them are ugly! Waugsberg Calliteara pudibunda, Pale Tussock Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 26 PEST CONTROL • Caterpillars: not all of them are ugly! Mjh233 Deilephila elpenor, Elephant Hawk Moth Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 27 PEST CONTROL • Caterpillars: not all of them are ugly! Slickers Georg Georg Orgyia antiqua, the Rusty Tussock Lenhard J. Gerald Acharia stimulea, the Saddleback caterpillar Clenet Csoka Patrick Aglais io, European Peacock Gyorgy Hypomecis roboraria, Great Oak Beauty Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 28 PEST CONTROL • Life cycle of caterpillars All developmental stages of the Monarch Butterfly (Danaus plexippus) Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 29 PEST CONTROL • Life cycle of caterpillars: not all stages inflict damage on plants Andy Potter Andy Pestana Ferran Adult Lepidoptera usually don‘t feed or only nectar, but lay eggs… Tony Wills Tony Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 30 PEST CONTROL • How can we control pests? - Toxins: chemical insecticides - Biological control: natural enemies Dr. Christine Becker: Effect of greenhouse light conditions on pest control Summerschool Volos, Greece, September 24-30, 2018 31 PEST CONTROL • Natural enemies: Parasitoids kill their hosts over time during own development Alvesgaspar A small braconid wasp laying an egg inside a Black Bean Aphid (Aphis fabae). The aphid is about 1 mm long. Dr.