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How to create a standing army of natural enemies in ornamental crops Gerben Messelink, Wageningen UR Greenhouse Horticulture Nursery/Floriculture Insect symposium, Watson Ville, December 12, 2013 Causes of poor establishment of natural enemies Lack of prey (low pest tolerance) Lack of plant provided food (nectar, pollen) No suitable sites for egg laying (oviposition) Unsuitable microclimate Predation or parasitism by other natural enemies Current solution for bad establishment: blowing natural enemies or by automatic releases with rotating dispensers…. or by introducing strips of rearing sachets…… Our view on biological control with natural enemies crop and climate adapted natural alternative food enemies standing army habitat enrichment lure & retain Outline of my presentation Banker plants Insectary plants Food sprays Mulch layers Hyperpredation Banker plant: Castor bean Ricinus communis Iphiseius degenerans Amblyseius swirskii Euseius ovalis Castor bean plant Ricinus communis Banker plants for Aphid parasitoids Most popular: combination of winter wheat & Sitobion avenae for production of Aphelinus abdominalis or Aphidius ervi ● Advantages: cheap rearing of parasitoids, “fresh” parasitoids ● Disadvantages: smaller wasps than on host from mass production, increased risk on hyperparasitism Huang et al., Critical Reviews in Plant Sciences 2011 Dominant hyperparasitoid: Dendrocerus aphidum Related to another common species: Dendrocerus carpenteri Parasitizes parasitized aphids 4-10 days after parasitism by the primary parasitoids Generalist species: most aphid-parasitoid combinations are vulnerable Conservation of Aphidoletes aphidimyza The banker plant method, similar to the parasitoids: combination of winter wheat & Sitobion avenae Intercropping with kohlrabi (with cabbage aphids) Banker planmts for Orius Possible candidates for Orius laevigatus in ornamentals Amaranthus cruentes (red amaranthus) Ornamental pepper: Capsicum ‘Black Pearl’ Corn flower, Centaurea cyanus Strawberry + strawberry whitefly, Aleyrodes lonicerae (not for roses) Insectary plants for nectar fuelling: conservation of Episyrphus balteatus Alyssum lobularia Insectary plants for nectar fuelling: conservation of Episyrphus balteatus Buckwheat, Fagopyrum esculentum Alternative food sources for the mirid predator Macrolophus pygmaeus 250 Produced offspring per 10 couples 200 150 100 50 0 untreated greenhouse Ephestia maize pollen Predfeed® Artemia (no food) whitefly eggs cysts Applying alternative food in practice Applying alternative food in practice 120 100 week 5 Density of M. pygmaeus/plant week 8 80 week 11 60 week 14 40 20 0 Petit Sweet Pommo Petit Sweet Pommo Petit Sweet Pommo Dolce Dolce Dolce Ephestia eggs Artemia cysts untreated (no food) Weekly application: Ephestia eggs: 35 g/ha (€800/kg) Artemia: 135 g/ha (€20/kg) Alternative food for predatory mites 2.5 a A A 2 A ab day 2 b day 3 Oviposition rate 1.5 1 c