J.C. van Lenteren
Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH Wageningen, The Netherlands
Introduction
Although the biological control of pests has been applied since around 1870, the large- scale commercial use of natural enemies of pests spans a period of less than 40 years. In some areas of agriculture, such as apple orchards, maize, cotton, sugarcane, soybean, vineyards and greenhouses, it has been a very successful, environmentally and economically sound, alternative for chemical pest control (van Lenteren et al., 1992; van Lenteren, 2000).
Inundative and seasonal inoculative releases of natural enemies are commercially applied primarily in annual field crops and green- house cultures and have increased consider- ably over the last 25 years (van Lenteren,
2000). Success of biological control in these crops is primarily dependent on the quality of the natural enemies, which are produced by commercial mass-rearing companies.
Today, more than 125 natural-enemy species are on the market for biological pest control (Table 11.1). Worldwide, there are about 85 commercial producers of natural enemies for augmentative forms of biological control with a turnover of about US$50 mil- lion in 2000 and an annual growth of 15–20%
(Bolckmans, 1999; K. Bolckmans, Berkel and Rodenrijs, The Netherlands, personal com- munication). In addition there are hundreds of state- or farmer-funded production units that may sell natural enemies (Chapter 1;
van Lenteren, 2000).
© CAB International 2003. Quality Control and Production of Biological Control Agents:
Theory and Testing Procedures (ed. J.C. van Lenteren) 167
Abstract
The commercial use of biological control has seen a very fast development during the past 30 years.
Currently, about 85 companies worldwide produce more than 125 species of natural enemies. The largest variety of commercially produced species of natural enemies is available in Europe, mainly as a result of a much larger greenhouse industry in Europe, although many species are also available in North America. Emerging markets are Latin America, Asia and (South) Africa. The most commonly sold nat- ural enemies are discussed in this chapter. The recommended release rates, the unit of sale and the target pest(s) are specified. In addition, a list of the commercially available biocontrol agents is provided, together with the target pests and the year of first use.
168 J.C. van Lenteren
Table 11.1. Commercially available natural enemies (parasitic insects, predatory insects, predatory mites and entomopathogenic nematodes, fungi, bacteria and viruses) of insects, mites and other invertebrate pests in Europe (situation in the year 2000).
Natural enemy (endemic/exotic) Pest (endemic/exotic) In use since
*Adalia bipunctata(en) Toxoptera aurantii (en) 1998
*Adoxophyes orana granulosis virus (en) Adoxophyes orana(en) 1995
*Aleochara bilineata(en) Deliaroot flies (en) 1995
Amblyseius barkeri(en) Thrips tabaci(en) 1981
Frankliniella occidentalis(ex) 1986 Amblyseius(Neioseiulus)degenerans(ex) Thrips (en, ex) 1993
Amblyseius fallacis (ex) Mites (ex) 1997
*Amblyseius largoensis (ex) Mites (ex) 1995
*Amblyseius lymonicus(ex) Thrips (en, ex) 1997
*Ampulex compressa(ex) Blattidae (en, ex) 1990
*Anagrus atomus(en) Cicadellidae (en, ex) 1990
*Anagyrus fusciventris(ex) Pseudococcidae (en,ex) 1995
*Anagyrus pseudococci(en) Pseudococcidae (en,ex) 1995
*Anthocoris nemorum(en) Thrips (en, ex) 1992
Aphelinus abdominalis(en) Macrosiphum euphorbiae(en) 1992
Aulacorthum solani(en) 1992
*Aphelinus mali(ex) Eriosoma lanigerum(ex) 1980
Aphidius colemani(ex) Aphis gossypii, Myzus persicae(ex, en) 1992
Aphidius ervi(en) Macrosiphum euphorbiae(en) 1996
Aulacorthum solani(en) 1996
Aphidius matricariae(en) Myzus persicae(en) 1990
*Aphidius urticae(en) Aulacorthum solani(en) 1990
Aphidoletes aphidimyza(en) Aphids (en, ex) 1989
*Aphytis holoxanthus(ex) Diaspididae (ex) 1996
*Aphytis melinus(ex) Diaspididae (en, ex) 1985
*Aprostocetus hagenowii(ex) Blattidae (en, ex) 1990
Bacillus thuringiensis(en, ex) Lepidoptera (en, ex) 1972
Beauveria brongniartii(en) Melolontha(en) 1985
*Bracon hebetor(ex) Lepidoptera (en) 1980
*Cales noacki (ex) Aleurothrixus floccosus (ex) 1970
*Chilocorus baileyi(ex) Diaspididae (en, ex) 1992
*Chilocorus circumdatus(ex) Diaspididae (en, ex) 1992
*Chilocorus nigritus(ex) Diaspididae, Asterolecaniidae (en, ex) 1985
*Chrysoperla carnea(en, ex) Aphids (en, ex) and others 1987
*Chrysoperla rufilabris(ex) Aphids (en, ex) and others 1987
*Clitostethus arcuatus (en) Aleyrodidae (ex) 1997
*Coccinella septempunctata(en) Aphids (en) 1980
*Coccophagus lycimnia(ex) Coccidae (en, ex) 1988
*Coccophagus rusti(ex) Coccidae (en, ex) 1988
*Coccophagus scutellaris(en) Coccidae (en, ex) 1986
*Coenosia attenuata(en) Diptera (en), Sciaridae (en) 1996
Agromyzidae (en, ex), Aleurodidae (ex) 1996
*Comperiella bifasciata(ex) Diaspididae (ex) 1985
*Cryptolaemus montrouzieri(ex) Pseudococcidae, Coccidae (en, ex),
Planococcus citri(ex) 1992
*Cydia pomonellagranulosis virus (en) Cydia pomonella(en) 1995
Dacnusa sibirica(en) Liriomyza bryoniae(en) 1981
Liriomyza trifolii(ex) 1981
Liriomyza huidobrensis(ex) 1990 Delphastus pusillus(ex) Trialeurodes vaporariorum(ex) 1993 Bemisia tabaci/argentifolii(ex) 1993
Continued
Commercial Availability of Biocontrol Agents 169
Table 11.1. Continued.
Natural enemy (endemic/exotic) Pest (endemic/exotic) In use since Dicyphus tamaninii(en) Whiteflies (ex), thrips (en, ex) 1996
Diglyphus isaea(en) Liriomyza bryoniae(en) 1984
Liriomyza trifolii(ex) 1984
Liriomyza huidobrensis(ex) 1990
*Diomussp. (ex) Phenacoccus manihoti(ex) 1990
*Encarsia citrina(ex) Diaspididae (en, ex) 1984
Encarsia formosa(ex)a Trialeurodes vaporariorum(ex) 1970 (1926) Bemisia tabaci/argentifolii(ex) 1988
Encarsia tricolor(en) Trialeurodes vaporariorum(ex) 1985
*Encyrtus infelix(ex) Coccidae (en, ex) 1990
*Encyrtus lecaniorum(en) Coccidae (en, ex) 1985
*Episyrphus balteatus(en) Aphids (en, ex) 1990
Eretmocerus californicus(ex) Bemisia tabaci/argentifolii(ex) 1995 Eretmocerus mundus(en) Bemisia tabaci/argentifolii(ex) 1995
*Franklinothrips vespiformis(ex) Thrips (ex) 1990
*Gyranusoideaspp. (ex) Pseudococcidae (en, ex) 1990
*Harmonia axyridis(ex) Aphids (en) 1995
Heterorhabditis bacteriophora Otiorrhynchus sulcatusand other spp. (en) 1984 Heterorhabditis megidis and other spp. (en, ex) Otiorrhynchus sulcatus and other spp. (en) 1984
*Hippodamia convergens(ex) Aphids (en, ex) 1993
*Hungariella peregrina(ex) Pseudococcidae (en, ex) 1990
*Hypoaspis aculeifer(en) Sciaridae, Rhizoglyphus echinopus(en) 1996 Rhizoglyphus rolini(en), thrips (en, ex) 1996
*Hypoaspis miles(en) Sciaridae, Rhizoglyphus echinopus(en) 1994
*Kampimodromus aberrans (en) Mites (Panonychus ulmi) (en) 1960
*Leptomastidea abnormis(en) Pseudococcidae (en, ex) 1984
*Leptomastix dactylopii(ex) Planococcus citri(en, ex) 1984
*Leptomastix epona(en) Pseudococcidae (en, ex) 1992
*Lysiphlebus fabarum(en) Aphis gossypii(ex) 1990
*Lysiphlebus testaceipes(ex) Aphis gossypii(ex) 1990
Macrolophus caliginosus(en) Whiteflies (ex) 1994
*Macrolophus pygmaeus (nubilis) (en) Whiteflies (ex) 1994
*Metaphycus bartletti(ex) Coccidae (en, ex) 1997
*Metaphycus helvolus(ex) Coccidae (en, ex) 1984
*Metaseiulus occidentalis(ex) Mites (en) 1993
*Microterys flavus (ex) Coccidae (en, ex) 1987
*Microterys nietneri(en) Coccidae (en, ex) 1987
*Muscidifurax zaraptor(ex) Stable flies (en) 1982
*Nasonia vitripennis(en) Stable flies (en) 1982
*Neoseiulus barkeri(en) Mites (en), thrips (en, ex) 1990
Neoseiulus(Amblyseius)californicus(ex) Mites (en, ex) 1995 Neoseiulus(Amblyseius)cucumeris(en, ex) Thrips tabaci(en) 1985 Frankliniella occidentalis(ex) 1986
Mites (en, ex) 1990
Neoseiulus(Amblyseius)cucumeris Thrips (en, ex) 1993
(ex, non-diapause strain)
*Nephus reunioni(ex) Pseudococcidae (en,ex) 1990
*Ooencyrtus kuwanae(ex) Moth (Lymantria dispar) (en) 1980
*Ooencyrtus pityocampae(ex) Thaumetopoea pityocampa(ex) 1997
*Ophyra aenescens (ex) Stable flies (en 2 spp.) 1995
Opius pallipes(en) Liriomyza bryoniae(en) 1980
Continued
170 J.C. van Lenteren
Table 11.1. Continued.
Natural enemy (endemic/exotic) Pest (endemic/exotic) In use since Oriusspp. (en, ex) F. occidentalis/T. tabaci(ex, en)
*Orius albidipennis(en) 1991
Orius insidiosus(ex) 1991
Orius laevigatus(en) 1995
*Orius majusculus(en) 1991
*Orius minutus(en) 1991
*Orius tristicolor(ex) 1995
*Paecilomyces fumosoroseus(en) Whiteflies (ex) 1997
*Phasmarhabditis hermaphrodita(en) Snails (en) 1994
*Phytoseiulus longipes(ex) Tetranychus urticae(en) 1990
Phytoseiulus persimilis(ex) Tetranychus urticae(en) 1968
*Picromerus bidens(en) Lepidoptera (en) 1990
*Podisus maculiventris(ex ?) Lepidoptera (en) 1996
Leptinotarsa decemlineata(ex) 1996
*Praon volucre(en) Aphids (en) 1990
*Pseudaphycus angelicus(ex) Pseudococcidae (en, ex) 1990
*Pseudaphycus flavidulus(en) Pseudococcidae (en, ex) 1990
*Pseudaphycus maculipennis(en) Pseudococcusspp. (en) 1980
*Rhyzobius chrysomeloides (ex) Matsococcus feytaudi (ex) 1997
*Rhyzobius(Lindorus)lophanthae(ex) Diaspididae (en, ex),
Pseudalacapsis pentagona 1980
*Rodolia cardinalis(ex) Icerya purchasi(ex) 1990
*Rumina decollata(en) Snails (en) 1990
*Scolothrips sexmaculatus(en) Mites, thrips (en, ex) 1990
*Scutellista caerulea (cyanea) (ex) Coccidae (en, ex) 1990
*Scymnus rubromaculatus(en) Aphids (en) 1990
*SpodopteraNPVirus (en) Spodoptera exigua(ex) 1994
*Steinernema carpocapsae(en) Otiorrhynchus sulcatusand other spp. (en) 1984
Steinernema feltiae(en) Sciaridae and other spp. (en) 1984
*Stethorus punctillum(en) Mites (en) 1995
*Stratiolaelaps miles(en) Sciaridae,Rhizoglyphus echinopus (en) 1994
*Sympherobiussp. (en) Pseudococcidae (en, ex) 1990
*Therodiplosis(=Feltiella)persicae(en) Mites in open fields (en) 1990
*Thripobius semiluteus(ex) Thrips (ex) 1995
*Trichogramma brassicae(en) Lepidoptera, several spp. (en) 1980
*Trichogramma cacoeciae(en) Lepidoptera, orchards, several spp. (en) 1980
*Trichogramma dendrolimi(en) Lepidoptera, orchards, several spp. (en) 1985 Trichogramma evanescens(en) Ostrinia nubilalisin maize (en) 1975 Lepidoptera in greenhouses (en, ex) 1992
*Typhlodromus pyri(en) Mites in apple, pear, grapes (en) 1985
*Verticillium lecanii(en) Whitefly/aphids (ex, en) 1990
*Small market products.
en, endemic: occurs in European Union countries; ex, exotic: originates from outside European Union countries, but may have been in Europe for 50 years or more; NPVirus, nucleopolyhedrovirus.
aEncarsiawas already used for biological control of whitefly between 1926 and 1945. Its use was terminated when synthetic pesticides became popular.
The commercial availability of natural enemies is changing continuously, although several of the larger producers have been on the market for a period of 30 years now,
which guarantees the permanent presence of the most important agents. Updated versions of commercially available biological control organisms, companies and suppliers are
published on a regular basis in the IPM Practitioner (Anon., 2000) and on the web (e.g. www.koppert.nl, www.biobest.be etc.).
Fewer than 30 beneficial species make up 90% of the total sales (Table 11.2; van Lenteren, 1997; Bolckmans, 1999). Extensive reviews of the availability of commercially produced biological control agents were not compiled until the mid-1990s, although some
data are given in van Lenteren and Woets (1988). Cranshaw et al. (1996) correctly state that such information is essential for making calculations on the cost-effectiveness of using such biological control organisms. Cranshaw et al. (1996) reviewed the 1994 pricing and marketing by suppliers of organisms for bio- logical control of arthropods in the USA. The same was done for Europe (van Lenteren et Commercial Availability of Biocontrol Agents 171
Table 11.2. Most commonly used biological control organisms in Europe and North America, and life stage in which the organism is shipped from producer.
Biological control organism Used in Species life stage
shipped
Amblyseius degenerans Europe Mixed life stages
Aphelinus abdominalis Europe Adult
Aphidius colemani Europe Pupa
Aphidius ervi Europe Pupa
Aphidoletes aphidimyza Europe + America Pupa
Aphytis melinus America + Europe Adult
Chrysoperla carnea andChrysoperla rufilibris America + Europe Eggs, larvae, adults or mixed
Cryptoleamus montrouzieri America + Europe Adult
Dacnusa sibirica Europe Adult
Delphastus pusillus Europe Adult
Diglyphus isea Europe Adult
Encarsia formosa Europe + America Pupa
Eretmocerus californicus America + Europe Pupa
Eretmocerus mundus Europe Pupa
Galendromus occidentalis America Mixed life stages
Harmonia axyridis Europe Adult
Heterohabditis megides Europe Juveniles
Hippodamia convergens America + Europe Adult
Hypoaspis aculeifer Europe Mixed life stages
Hypoaspis miles Europe Mixed life stages
Leptomastix abnormis Europe Adult
Leptomastix dactylopii Europe Adult
Leptomastix epona Europe Adult
Macrolophus caliginosus Europe Adult
Mesoseiulus longipes America Mixed life stages
Metaphycus helvolus America + Europe Adult
Neoseiulus (Amblyseius) californicus Europe + America Mixed life stages Neoseiulus (Amblyseius) cucumeris Europe + America Mixed life stages
Orius insidiosus America Adult
Orius laevigatus Europe Adult
Orius majusculus Europe Adult
Phytoseiulus persimilis Europe + America Mixed life stages
Steinernema carpocapsae America Juveniles
Steinernema feltiae Europe + America Juveniles
Trichogramma brassicae Europe Parasitized host egg
Trichogramma evanescens America + Europe Parasitized host egg
Trichogramma spp. America + Europe Parasitized host egg
Fly parasitoids America + Europe Pupa
al., 1997). The most commonly sold species in Europe and North America are discussed in this chapter (Table 11.2). These species are divided into four groups: parasitoids, preda- tory insects, predatory mites and ento- mopathogenic nematodes. Most natural enemies are used for biological control in greenhouses, with the exception of Harmonia sp. and Trichogramma spp., which are also used in the open field.
Parasitoids
Aphelinus abdominalisDalman This parasitic wasp is used to control the potato aphid Macrosiphum euphorbiae (Thomas) and the greenhouse potato aphid Aulacorthum solani Kaltenbach. It is sold in units of 100 or 250 adults or pupae. Since A.
abdominalis does not easily spread over the crop, it should be introduced where aphid foci occur (Koppert, 1994). The recommended rates for release range from two to four wasps m2 in the focal point of the infesta- tion. Usually, A. abdominalisis used in combi- nation with Aphidoletes aphidimyza Rondani.
Aphidius colemaniViereck
This species is a parasitoid of the cotton aphid Aphis gossypii Glover and the green peach aphid Myzus persicae Sulzer. The rec- ommended rate for release ranges from 0.15 m2for preventive introductions to 1.5 m2 in heavily infected areas.
Aphidius ervi Halliday
This parasitoid is used to control the potato aphid M. euphorbiae. The recommended release rate ranges from 0.15 m2to 1 m2.
Aphytis melinus DeBach
This species is sold for control of armoured scales (e.g. California red scale, yellow scale, and oleander scale). The suggested release
rates are in the order of five to 100 adults per infested plant.
Dacnusa sibirica Telenga
This species is used to control leafminers such as the tomato leafminer Liriomyza bry- oniae (Kaltenbach), the American serpentine leafminer Liriomyza trifolii(Burgess) and the pea leafminer Liriomyza huidobrensis (Blanchard). D. sibiricais supplied in units of 250 adults. This parasitoid is advised for use mainly during the winter in northern Europe.
Diglyphus isea (Walker)
This parasitoid is also used for controlling leafminers and it is sometimes sold with D.
sibiricain mixed culture. It is sold in units of 250 adults. The recommended introduction rate (mostly mixed with D. sibirica) ranges from 0.25 m2for preventative introductions to 2 m2in heavily infested areas.
Encarsia formosaGahan
This is a parasitoid of the greenhouse white- fly Trialeurodes vaporariorum(Westwood) and the whiteflies Bemisia tabaci(Gennadius) and Bemisia argentifoliiBellows and Perring, and is one of the most remarkable examples of the potential of a biological control agent (van Lenteren et al., 1996). The small para- sitoid was accidentally imported into Europe – as was greenhouse whitefly – and was dis- covered as a parasitoid of whiteflies by Speyer (1927). Shortly after its discovery, it became very popular in the 1930s, both in Europe and elsewhere. After the second world war, its use declined because of the availability of broad-spectrum insecticides.
Nowadays, E. formosa is one of the most used biological control agents in protected crops, and also the most important natural enemy when expressed in monetary value for pro- ducers (van Lenteren, 1995; Bolckmans, 1999). E. formosa is produced in enormous numbers. The annual production by large companies is about half a billion parasitoids.
172 J.C. van Lenteren
E. formosais usually sold in units of 1000 as parasitized whitefly pupae, either on the leaf of its whitefly host plant, as pupae glued to different substrates or as pupae that are removed from a leaf. The recommended rate of release ranges from 1 m2, every 1–2 weeks, during a certain period for preven- tive use, to 9 m2, five times a week, for a severe infestation.
Eretmocerus californicusHoward The recommended rate of release of this par- asitoid of Bemisia spp. varies from 1.5 m2 every 1–2 weeks for preventive use to 9 m2 three times a week in a severe infestation of whiteflies.
Eretmocerus mundus Mercet This parasitoid is also used for control of Bemisia spp., particularly in the Mediterranean area of Europe. Advice for releases is the same as for E. californicus.
Fly parasitoids
Fly parasitoids include various species of par- asitic wasps that develop on pupae of manure-breeding flies, such as Muscidifurax spp., Spalangia spp. and Nasoniaspp. They are used to reduce nuisance-fly problems by owners of horses and to control flies in feed- lots and other animal rearing facilities, as well as around composting areas. Release rates and moments vary a lot; one commonly sug- gested release rate was 500 parasitoids per large animal at biweekly or monthly intervals, another release rate was related to the area to be protected, such as 1000 parasitoids 100 ft2. The most common unit package marketed included 8000–10,000 fly parasitoids (all infor- mation from Cranshaw et al., 1996).
Leptomastix abnormisGirault This is a parasitic wasp of mealybugs; see under Leptomastix dactylopii.
Leptomastix dactylopii(Howard) This species parasitizes the citrus mealybug Planococcus citri (Risso). It is recommended to introduce one wasp m2in a light infesta- tion and two wasps m2in a severe infesta- tion of P. citri. Wasps should be introduced every 2 weeks.
Leptomastix epona(Walker)
This species is also a parasitoid of P. citri; see under L. dactylopiiabove.
Metaphycus helvolus(Compere) This is the most common parasitoid sold for control of soft scales (e.g. hemispherical scale, black scale, nigra scale and soft brown scale).
Recommended use rates: two to three releases at 2–3-week intervals of five to ten parasitoids per infested plant (Cranshaw et al., 1996).
Trichogrammaspp.
These species parasitize different lepidopteran pests. Trichogramma spp. are egg parasitoids and are supplied as black pupae attached to cardboard cards, as loose pupae in containers, in capsules or in other formulations. A multi- tude of species are produced and sold. The rec- ommended rate of release in greenhouses ranges from 5 m2for preventive use to 20 m2 in a severe infestation. In greenhouses, pupae should be introduced weekly. In maize with one generation of Ostrinia nubilalis(Hubner) in northern Europe, one release of 100,000 pupae of different ages per hectare is advised; pupae will emerge during a 2-week period. In North America, the numbers released in field crops are similar to or higher than those advised in Europe (Cranshaw et al., 1996).
Predatory Insects Aphidoletes aphidimyza (Rondani) This gall midge is used for controlling aphids. The adult gall midges are active at Commercial Availability of Biocontrol Agents 173
night. The female gall midge deposits small orange eggs near the aphids. The emerging larvae paralyse the aphids and suck them dry (Koppert, 1994). A. aphidimyzais sold as black pupae in a vermiculite carrier. The rec- ommended rate of release varies from 2 m2 to 10 m2, depending on the seriousness of an infestation.
Chrysoperla spp.
Two species of green lacewings, Chrysoperla carnea Stehphens and Chrysoperla rufilibris (Burmeister), are produced and used as predators of aphids. The recommended rate of release for C. carnea, the most common one, ranges from 10 m2in a light infestation to 20 m2in a severe infestation.
Cryptolaemus montrouzieriMulsant This is a predator of mealybugs. Both the adult beetle and its larvae can kill all growth stages of the mealybug (Koppert, 1994). The beetle is particularly useful for controlling large mealybug populations. The recom- mended rate of release in Europe varies from 2 m2when introduced twice with an inter- val of 2 weeks, to 10 m2when introduced once in mealybug hot spots. In North America, the release rates are highly vari- able; an example is a release rate of two to five beetles per infested plant (Cranshaw et al., 1996).
Delphastus pusillus(LeConte) This predatory beetle is used for controlling T. vaporariorumand Bemisiaspp. It is usually sold in units of 100 adults. As it is a rather new natural enemy, release rates are still highly variable.
Ladybirds
Two species of ladybird are commercially used as biological control agents against aphids. Adult beetles of the species
Hippodamia convergens Guerin-Meneville are collected in enormous quantities in the USA.
This species is not produced in Europe. It is introduced once during the production sea- son. The recommended release rate ranges from 25 m2 to 50 m2. Harmonia axyridis (Pallas) is a ladybird originating from Asia and advised for use against various aphids.
Macrolophus caliginosusWagner M. caliginosusis a predatory bug used for con- trolling the tobacco/silverleaf whitefly B.
tabaci/argentifoliiand the greenhouse whitefly T. vaporariorum. This predatory bug pierces the prey with its sucking mouthparts and sucks out the body fluids. It preys on all whitefly stages, but prefers eggs and larvae.
An adult bug may feed on 30–40 whitefly eggs a day (Koppert, 1994). M. caliginosusis sold as adults in a vermiculite carrier. It is rec- ommended for release of 0.5 m2to 5 preda- tors m2twice, at an interval of 2 weeks.
Oriusspp.
These predatory species are used to control thrips, such as the onion thrips, Thrips tabaci Lindeman, and the western flower thrips, Frankliniella occidentalis (Pergande). Orius spp. attack larvae and adult thrips. An adult predatory bug can eat five to 20 thrips a day (Koppert, 1994). The recommended rate of release ranges from 1 m2 to 10 m2, depending on the level of pest infestation.
Currently, there are about five Orius species on the commercial market. The most popular species in Europe is Orius laevigatus Fieber;
in North America, Orius insidiosus (Say) is sold most often.
Predatory Mites
Amblyseius (Neoseiulus)cucumeris (Oudemans)
A. cucumeris is marketed as a predator of western flower thrips (F. occidentalis). This species of thrips is currently the most prob- 174 J.C. van Lenteren