Presentpractice practice, ongoingresearch and future potential for non chemical pest management in vegetable production in Denmark
Outline Danishvegetable area Available non chemical pest control methods and their use in field crops Available non chemical pest control methods and their use in greenhouse crops Ongoing research Future perspectives
Area with vegetables Greenhouses 120 ha Major crops: cucumber, tomato, lettuce Outdoor crops 11,150 ha (1,580 ha organic) Major crops: pea, carrot, onion, cabbage, lettuce (organic: carrot, pea, cabbage, onion, lettuce)
Field, available methods
Field, common practice Varieties with (partial) pest resistance Available for a number of vegetable species e.g. lettuce lettuce aphid; cabbage cabbage root fly Sometimes plant characteristics relating to yield / quality / appearance is preferred by growers Cultural considerations to reduce pest infestationsbased oncommon knowledge on pest biology e.g. avoid growing glettuce next to poplar p hedges e.g. avoid carrot fields close to hedges
Field, common practice General sanitation, crop rotation Most growers are aware of the importance of general sanitation, removal of infested crop residues, keeping distance to fields of previous year etc. Most growers used sound crop rotation programs according to present knowledge New initiative employed by some growers is to practice withinyear shift in location of production (satellite production) e.g. relocating production of lettuce between 3 different and distantly remote locations within the same cropping year
Field, organic production Botanicals and the like Watering e.g. garlic extract used against cabbage root fly e.g. iron phosphate (with attractant) used against slugs Recommended against aphids in e.g. beans, peas; thrips in garlic against small larvae of cutworms in onions, carrot monitoring /warning exploited extent of use unknown
Field, organic production Floatingrow cover / netting Used in some cultures, e.g. against aphids, cabbage root flies, carrot flies, birds expensive, microclimatechanges, reduced access for beneficials covering period may be reduced if monitoring/warning available Insect fences Good results against cabbage root flies in Norway not verified for Denmark; use probably nil Timing of planting / harvest e.g. establish carrots later thanpeakflight of1 1. generation carrot flies / harvest carrots prior to critical damage by 2. generation carrot fly larvae monitoring /warning available ailable
Field, organic production Alternative food Use in practice = unknown Trap crops e.g. plant sunflower near cabbage to divert birds from the crop Seemingly no practical use yet e.g. planting of broccoli around areas with infestations last year of swede midge to prevent infestation of this years cabbage e.g. planting of rape in as perimeter trap crop around cabbage to trap/divert Lepidoptera
Field, organic production Undersowing / cover crops / intercropping Might be employed for other reasons than pest control but may act to confuse pests and increase presence of natural enemies Various possibilities have been recommended for pest control but present practical implementation unknown e.g. against root flies in cabbage and onion
Field, organic production Conservation biocontrol Direct measures aimed at promoting natural enemy diversity Flower strips, beetle banks e.g. flower strips employed by some organic lettuce growers Nesting sites/boxes for insectivorous birds Increase general farm biodiversity i establish new hedges, in field habitats e.g. practiced by some larger organic producers Sabine Ravnskov
Field Augmentation biological control Microorganisms e.g. Bacillus thuriengiensis used against Lepidoptera in e.g. cabbage (conventional, organic) e.g. nematodes used against slugs, snails (conventional, organic) Predators, parasitoids Trichogramma brassicae available against Lepidoptera in cabbage (2 releases in spring); pheromone traps available for timing of applications extent of use unknown, presumably small (organic)
Greenhouses, available methods
Greenhouse, common practice General sanitation Insect nets for vents to reduce influx of pests Masstrappingwithsticky sticky rolls Botanicals, e.g. garlic extract Insecticidal soap Augmentative biological control 25 30 predators/parasitoids/microorganisms available Long tradition used routinely by almost all Danish producers of vegetables Preventive uses / timing through monitoring (sticky traps, pheromone traps) or scouting
Ongoing research Greenhouse crops Not much at present Field crops Agricultural landscapes / agroecosystems effects on pests, natural enemies and pest regulation Pest management in organic farms Development of IPM strategies Pest biocontrol Basic ecological and biological studies of pests and natural enemies
Perspectives Field crops Biocontrol in field vegetables still rather restricted Development and implementation of additional methods, combinations of methods needed Pest orientated Cropping system orientated Development and implementation of holistic IPM programs for control of diseases, pests and weeds needed, including development of non biological methods where relevant exploitation of agroecosystem services in plant protection Greenhouse crops Appearance of new pest species / increased production of new greenhouse vegetables (e.g. herbs, leek) requires research for development of IPM and biocontrol strategies