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Beneficial insects, predatory mites and entomopathogenic nematodes: 37 species with their biology and release rates

Beneficial insects and mites: Coccinella septempunctata, Chrysoperla carnea, Phytoseiulus persimilis, Trichogramma, hoverflies and Orius laevigatus
Six of the organisms covered here. Four are sold in Greece today as commercial preparations, one is a mite rather than an insect, and two appear on the Greek national list but are not offered by the three suppliers examined. Section 8 sets out the distinction.

Savvas Pastopoulos, Agronomist MSc, Pastopoulos Agronomics, Neos Mylotopos, Pella, Greece

Beneficial insects, predatory mites and entomopathogenic nematodes are living organisms released into a crop to eat or to parasitise the pest. They are not plant protection products. They carry no marketing authorisation number, no dose in grams and no pre-harvest interval. What they do have, and what chemical products do not, is a life cycle, and that is what decides whether a release succeeds or fails. When to release, at what temperature, at what humidity, onto which leaf surface and against which stage of the pest all follow from the biology rather than from a label. This article covers thirty-seven species available on the Greek market, with published temperature thresholds, release rates, the Greek legal framework and the documented reasons releases fail.

Units used here

Release rates are given per square metre, per plant or per hectare, as the original sources give them. One hectare is 10,000 square metres and equals 10 Greek stremmata. Where a source reports a rate per acre, the acre figure is kept and the hectare equivalent is given beside it, because converting and rounding twice introduces error. Decimal points are points and thousands separators are commas throughout.

The first thing to be clear about

None of the thirty-seven species in this article holds an authorisation from the Greek Ministry of Rural Development and Food in the sense that a chemical product does, and none appears in the Greek plant protection product database at fyto.plantprotect.gr. That does not mean they circulate without rules. It means they fall under a different regime, set out in section 1. A preparation of beneficials in Greece carries a registration number in the national catalogue of preparations containing macro-organisms, not an authorisation number, and that is the question to put to a supplier.

37species covered
53species on the Greek national list
0authorisation numbers, correctly so
0.168the predator to prey ratio above which Nesidiocoris costs money

1. Why they hold no authorisation, and what they hold instead

Regulation (EC) No 1107/2009 defines a substance in Article 3 as a chemical element or compound, and a micro-organism as any microbiological entity including lower fungi and viruses. A predatory mite is neither a chemical compound nor a microbiological entity. The word macro-organism appears nowhere in the Regulation [76]. They fall outside it by definition rather than through an express exclusion, and that is why there is no active substance approval, no authorisation number, no maximum residue level and no pre-harvest interval.

This is where the usual conclusion stops, and this is exactly where it goes wrong. Greece does regulate beneficial macro-organisms, through a separate instrument. Ministerial Decision 10522/117908 of 22 September 2014 establishes a National Catalogue of Plant Protection Preparations containing Macro-organisms, and Article 2(3) expressly prohibits the production, import and placing on the market of any preparation not registered in it. Article 6(1) requires the registration number to be printed on the label, together with the species and the number of individuals [74].

A second filter matters more than the first. Articles 4(1) and 6(3) permit import only for organisms listed either on the National Catalogue of Macro-organisms or on the EPPO list [74]. The Greek catalogue currently holds fifty-three species [75], and the corresponding EPPO instrument is Standard PM 6/3, which lists agents used in the EPPO region with no adverse effects or with acceptable ones [73]. The dual wording has a practical consequence. Franklinothrips vespiformis, for instance, is not on the Greek catalogue but is in Appendix 1 of PM 6/3, so it can be imported lawfully by that second route.

The right question to put to a supplier

Not the authorisation number, because none exists and none will. Two questions instead. First, what is the preparation's registration number in the national catalogue. Second, is the species on the Greek national catalogue or on the EPPO PM 6/3 list. If both answers are yes, the preparation circulates lawfully. If there is no registration number, marketing it is expressly prohibited by Article 2(3).

Technical evaluation of applications is carried out by the Biological Control Laboratory of the Benaki Phytopathological Institute, while the competent authority is the Directorate of Plant Produce Protection of the Ministry [74]. The same model, national registration rather than European authorisation, applies with variations across the Union, which is why a preparation lawful in Spain is not automatically lawful in Greece [78].

Nematodes

Entomopathogenic nematodes follow the same logic. A nematode is a multicellular animal and therefore not a microbiological entity under Article 3, and Greece classifies them explicitly as macro-organisms: Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae and Steinernema kraussei each have their own entry on the national catalogue [75]. There is however one real difference. Nematodes obligatorily carry symbiotic bacteria, and for that reason several countries ask for data on the bacterium during registration, which they never do for insects and mites [78].

Organic production

Regulation (EU) 2018/848, Annex II, Part I, point 1.10.1 names protection by natural enemies as the first of the preventive plant protection measures. Point 1.10.2, which refers to the authorisation regime of Article 24, concerns products and substances. A living predator is neither. Releasing beneficial macro-organisms in an organic crop therefore requires no input authorisation and appears on no input list; it is simply a permitted and indeed prioritised cultural measure [77].

Sources: 73 74 75 76 77 78

2. The three modes of action and why the distinction is practical

Dividing the agents into predators, parasitoids and entomopathogenic nematodes is not taxonomic bookkeeping. It determines three things a grower can see in the field: how many pest individuals each agent kills over its lifetime, how long before the result shows, and what exactly needs to be counted to know whether it worked.

Predators

They kill many pest individuals over their lifetime, usually as both immatures and adults. The result appears relatively quickly and monitoring is by direct observation of the predator itself. Two exceptions change everything: in the green lacewing and in both gall midges only the larva is predatory, while the adult feeds on pollen, nectar and honeydew.

Parasitoids

Each individual develops in or on a single host, which it eventually kills. The number of hosts destroyed equals the number of eggs laid, plus those the female kills by feeding on them without laying. The distinction between koinobionts and idiobionts is purely practical here. A koinobiont leaves the host alive and feeding for days, so damage does not stop at once. An idiobiont paralyses it on the spot, so damage stops at the moment of attack.

Entomopathogenic nematodes

The third-stage infective juvenile, the only free-living and non-feeding stage, enters the host and releases its symbiotic bacterium. The host usually dies within twenty-four to forty-eight hours, the nematode reproduces inside the cadaver for two or three generations, and new infective juveniles emerge to find another host. The great advantage is that they reach the stages living inside soil or wood, where no spray and no canopy predator has any access.

Above these three categories sits a fourth distinction, which describes not the organism but the strategy: conserving populations already present, classical introduction of an exotic agent for permanent establishment, and augmentative release of mass-reared individuals [80]. Augmentative biological control now offers more than two hundred commercial species worldwide, and the standing paradox of the field is that actual uptake remains far below availability [79]. Research has not stopped: recent directions concern mass rearing, compatibility between agents, and conservation of populations within the agroecosystem [81].

This article is mainly about the third strategy, with two notable exceptions. Rodolia cardinalis is already established throughout the Mediterranean and is not purchased, while Amblyseius andersoni overwinters in the leaf litter and in perennial crops can be conserved rather than bought again each year [16].

A warning about identification

Rigorous morphological study confirmed that Chilocorus kuwanae and Chilocorus renipustulatus are the same species. For decades, therefore, releases of supposedly introduced C. kuwanae in Europe and the Caucasus were in fact releasing a native species, and did not constitute classical biological control at all [95]. The example shows how expensive a misidentification is, and why the name on the box deserves checking.

Sources: 16 73 79 80 81 95

3. The selection tool, by crop and by pest

What the tool does and what it does not do

Select one crop and one or more pests, and the tool ranks the beneficial organisms by how much of the selection each one accounts for. The percentage is not a probability of success. One hundred percent means only that the species covers every pest selected at the highest available weight. Species that the producer or the literature excludes from that crop do not appear at all, and the reason is stated. The tool replaces neither an on-site assessment nor the temperature and humidity checks given on each species card.

Which beneficial organism fits

1. Crop
2. Pest, more than one may be selected

Sources: 2 13 73 90

4. Canopy predatory mites

Phytoseiid mites are the most widely used group of beneficials in the world, and the choice between them rests on a classification published in 1997 that remains the working tool. The species fall into four feeding types [1]. Type I is the specialist spider mite predator, that is Phytoseiulus, which eats nothing else and does not survive without its prey. Type II is selective, preferring spider mites but tolerating pollen. Type III is generalist, taking thrips, whiteflies, eriophyids and pollen, and only this type can be established preventively, before the pest appears. Type IV feeds mainly on pollen and is not represented here.

The practical meaning is simple and not said often enough. A Type I species is curative. It goes in when the spider mite is already present, cleans up, and then dies or leaves. A Type III species is preventive. It goes in first, lives on pollen, and waits. Buying Type I for prevention is money thrown away, and buying Type III to clear an established spider mite focus is time thrown away.

A rule that applies to every generalist phytoseiid

The technical sheets of the four generalist species, cucumeris, swirskii, andersoni and limonicus, each independently carry the same warning: they are not to be combined with one another or with montdorensis [90]. The reason is intraguild predation, that is, they eat each other. Choose one generalist predatory mite per crop, not a mixture. The two substrate mites in the next section are the exception: they are expressly recommended together with a canopy predator, because they work on a different floor.

Why almost every sheet says not on tomato

This is a mechanism, not a commercial caveat. The glandular trichomes of tomato do not merely impede movement, they are toxic to nymphs and adults [2]. Subtype III-b of the 2013 revision is defined precisely as those species preferring glabrous leaves with little or no trichomes [2], and that single term predicts the whole commercial pattern: excellent performance on sweet pepper and cucumber, none at all on tomato.

Phytoseiulus persimilis

Phytoseiidae. Predatory mite, spider mite specialist

Spider mites not on tomato

Temperature
13 to 27 degrees, ineffective above 30
Relative humidity
above 70 percent, critical
Release rate
2 to 50 individuals per square metre per release
Availability and legal status
Koppert, Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersAt 60 percent relative humidity fewer than 20 percent of eggs hatch, and no commercial strain is more tolerant than any other.

Sources: 3 73

Neoseiulus californicus

Phytoseiidae. Predatory mite, selective on spider mites

Spider mites Eriophyid and tarsonemid mites Thrips, secondary not on tomato

Temperature
lower developmental threshold 10.3 degrees, thermal constant 86.2 degree-days, no egg hatch at 37.5
Relative humidity
sensitive below 60 percent
Release rate
25 to 125 per square metre, at least five times at weekly intervals
Availability and legal status
Koppert, Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt survives on pollen and tolerates ten days of starvation without losing fecundity, so it can be released preventively. EPPO accepts only non-diapausing strains.

Sources: 5 73

Neoseiulus cucumeris

Phytoseiidae. Predatory mite, generalist

Thrips Eriophyid and tarsonemid mites Spider mites, secondary Whiteflies, secondary not on tomato

Temperature
most effective 15 to 25 degrees according to the producer, ineffective above 30
Relative humidity
above 70 percent
Release rate
50 to 100 per square metre, up to 350 at peak pressure, at least 4,000 introduction points per hectare
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt takes only young thrips larvae, never adults. It cannot be combined with any other generalist predatory mite.

Sources: 13 14 73

Amblyseius swirskii

Phytoseiidae. Predatory mite, generalist

Thrips Whiteflies Eriophyid and tarsonemid mites Spider mites, secondary not on tomato not on cucumber and cucurbits

Temperature
lower developmental threshold 11.3 degrees, but the population does NOT grow below 15.5. Optimum 30.1, upper threshold 37.4
Relative humidity
optimum 55 to 85 percent, eggs desiccate below 40
Release rate
25 to 300 per square metre
Availability and legal status
Koppert, Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe gap between the developmental threshold and the population growth threshold explains why it fails in a cool spring greenhouse. It is native to the eastern Mediterranean, Greece included.

Sources: 2 4 73

Amblyseius andersoni

Phytoseiidae. Predatory mite, generalist, overwintering

Eriophyid and tarsonemid mites Spider mites Thrips, secondary not on tomato

Temperature
eggs do not hatch at 16, full development 17 to 35 degrees, optimum 20 to 28
Relative humidity
sensitive below 65 percent
Release rate
50 to 250 per square metre, at least three times at weekly intervals
Availability and legal status
Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe only one of the seven that overwinters in the leaf litter and climbs into the canopy on its own in spring, so in perennial crops it can be conserved rather than repurchased.

Sources: 6 16 73

Amblydromalus limonicus

Phytoseiidae. Predatory mite, generalist, cool-tolerant

Thrips Whiteflies not on tomato

Temperature
tolerates lower temperatures than swirskii, but no numerical limits have been published
Relative humidity
no published curve
Release rate
50 to 250 per square metre
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersOn a diet of spider mites alone it lays 0.009 eggs per female per day, which means it effectively does not reproduce. On cattail pollen it reaches 1.6. It is not a spider mite agent but a thrips and whitefly agent.

Sources: 7 8 73

Transeius montdorensis

Phytoseiidae. Predatory mite, generalist

Thrips Whiteflies Eriophyid and tarsonemid mites, secondary Spider mites, secondary not on tomato

Temperature
lower developmental threshold 10.3 to 10.7 degrees, thrives 20 to 30, adults tolerate up to 45 but the eggs do not
Relative humidity
above 60 percent for eggs to hatch
Release rate
no release rate was found, from either a producer sheet or peer-reviewed work
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIts intrinsic rate of increase reaches 0.41 per day, among the highest measured in a phytoseiid. It cannot be monitored visually, establishment shows only through the decline of the pest.

Sources: 73

Sources: 1 2 3 4 5 6 7 8 13 14 15 16 73 90

5. Substrate predatory mites

Thrips spend two of their stages inside the growing medium, where no canopy predator and no foliar spray reaches them. Sciarid flies spend their whole larval life there. The two substrate mites in this section cover exactly that floor, and for that reason they do not compete with the phytoseiids above but complement them.

What the commercial description omits

First, Stratiolaelaps scimitus eats neither the eggs nor the pupae of sciarid flies. In a controlled study every larval instar was attacked, but egg predation was negligible and pupae were not attacked at all [9], while the producer sheet claims control of all three stages [90]. Second, it lives only in the top two and a half centimetres of the medium [12], so anything pupating deeper escapes it. The same source, which is a university publication rather than a commercial one, concludes explicitly that the species alone is usually not sufficient.

Stratiolaelaps scimitus

Laelapidae. Soil-dwelling predatory mite

Sciarid flies and thrips pupae in the substrate Thrips, secondary

Temperature
lower developmental threshold 10 to 12 degrees, optimum 15 to 30, activity reduced below 14. Egg to adult 34 days at 15 and 10 at 28
Relative humidity
this concerns substrate moisture, not air humidity
Release rate
100 to 500 per square metre
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt touches neither the eggs nor the pupae of sciarid flies, only the larvae, and it lives only in the top 2.5 centimetres of the medium. On its own it does not suffice.

Sources: 9 10 12 73

Macrocheles robustulus

Macrochelidae. Soil-dwelling predatory mite

Sciarid flies and thrips pupae in the substrate Thrips

Temperature
minimum application temperature 15 degrees, no other limits have been published
Relative humidity
this concerns substrate moisture
Release rate
100 to 500 per square metre
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersNo life table has been published for the species. Its commercial use rests on efficacy trials rather than on characterised biology, and that deserves to be said.

Sources: 11 73

Sources: 9 10 11 12 73 90

6. Predatory insects

Fifteen species from seven families, with three differences that govern their use. The first is where they lay. Anthocorids and mirids insert their eggs into plant tissue, so they cannot be counted, cannot be washed off, and establishment cannot be verified by counting eggs. In Anthocoris nemoralis eggs deposited outside plant tissue simply failed to hatch [21]. Ladybirds by contrast lay in clusters on the leaf, so the eggs can be counted but can also be sprayed.

The second is which stage feeds. In ten of the fifteen species both immatures and adults are predatory. In the green lacewing and both gall midges only the larva is predatory, and the adult feeds exclusively on pollen, nectar and honeydew [85]. That changes two things in practice: a pollen source in or beside the crop is needed to retain the adults, and most lacewing adults leave the greenhouse in any case [90].

The third is photoperiod, and this is where Greek conditions differ materially from northern European ones. Section 13 covers it.

Anthocorids

Orius laevigatus

Anthocoridae. Predatory bug

Thrips Whiteflies, secondary Spider mites, secondary

Temperature
optimum above 20 degrees, reduced performance above 30. Egg to adult 9.6 days at 26
Release rate
2 per square metre gave the same thrips control as 6 in greenhouse sweet pepper. The producer gives 0.5 to 10, in groups of at least 50 individuals
Availability and legal status
Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt inserts its eggs INTO plant tissue, so they cannot be counted and cannot be washed off. A nymph eats about 54 thrips larvae over its development, an adult up to 20 a day.

Sources: 17 18

Orius majusculus

Anthocoridae. Predatory bug

Thrips Whiteflies, secondary

Temperature
no published thresholds were found
Release rate
no published release rate was found
Availability and legal status
Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe southern strain from Antalya, at the same latitude as the Peloponnese, enters reproductive diapause at 11.5 hours of light in 100 percent of females and at 12 hours in 25 percent. The northern strain needs 14 to 16 hours. An autumn release of a northern strain in Greece simply stops reproducing.

Sources: 19 20

Anthocoris nemoralis

Anthocoridae. Predatory bug

Pear and olive psyllids Thrips, secondary Aphids, secondary Spider mites, secondary Lepidopteran eggs (codling moth and others), secondary

Temperature
no published threshold was found for the species
Release rate
1,500 to 2,000 individuals per hectare, in two to four releases in consecutive weeks
Availability and legal status
Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersOn natural psyllid prey it starts laying after 7.1 days. On a laboratory diet of Ephestia eggs the same period becomes 83.7 days, twelve times longer. A mass-reared population carries that delay into the orchard.

Sources: 21

Mirids, and the zoophytophagy problem

Of all the agents in this list the two mirids are at once the most effective and the most hazardous. They are zoophytophagous, feeding on both insects and plant. The nymph of Macrolophus pygmaeus completes development with no prey at all, needing roughly twenty percent more degree-days, 306 to 361 instead of 253 to 280 [22]. That very capacity keeps it in the crop when no pest is present, and that very capacity lets it feed on the plant once the pest is gone.

The Nesidiocoris trap, with numbers

The three values that govern use of this species come from field trials in southern Spain [25]:

  • Below 0.65 individuals per leaf there is no yield reduction, whether or not whitefly is present.
  • Up to 5 individuals per leaf are safe, provided more than 26 whitefly immatures per leaf are present. Abundant prey suppresses plant feeding.
  • Once the predator to prey ratio exceeds 0.168, the probability of yield loss rises. Roughly, more than about one Nesidiocoris per six whitefly immatures and the crop starts paying.

The way the same paper puts the timing is the most useful guidance for a decision in the glasshouse: yield reduction occurs after the predator population peaks, once whitefly numbers have already been reduced. The crop is damaged precisely when biological control has succeeded. The success creates the failure.

The consequence for the rate is that it is set by the damage, not by the efficacy. In pre-plant release trials at 0, 0.5, 1 and 2 individuals per plant, every rate significantly reduced whitefly and gave adequate control. Only 0.5 per plant did not increase crop damage [26]. Two independent papers therefore converge on the same protocol: one individual per two plants, in the transplant trays, five days before planting out [27].

Macrolophus has the reputation of being the safer of the two, and broadly it is, but the difference is not the one usually assumed. At high density, around 23.8 individuals per plant, flower abortion reached 12.2 percent and mean fruit weight also fell, whereas with Nesidiocoris the plant compensates for flower abortion by increasing the weight of the fruits that remain [24]. That is, Macrolophus does less damage, but without compensation.

Macrolophus pygmaeus

Miridae. Zoophytophagous predatory bug

Whiteflies Tuta absoluta Spider mites, secondary Aphids, secondary

Temperature
egg-to-egg threshold 8.5 degrees, thermal constant 533 to 541 degree-days
Release rate
The published strategy is 20 adults per plant with supplementary food for six to eight weeks. That figure describes a concentrated release, not a whole-crop dose.
Availability and legal status
Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe nymph completes development with NO prey at all, needing roughly 20 percent more degree-days. That is what keeps it in the crop through prey-free periods, and that is exactly what allows it to feed on the plant.

Sources: 22 23 24 91 92

Nesidiocoris tenuis

Miridae. Zoophytophagous predatory bug

Tuta absoluta Whiteflies Spider mites, secondary Aphids, secondary

Temperature
one generation in 14.9 days at 35 degrees, 21.8 at 25 and 86.7 at 15
Release rate
0.5 individuals per plant, pre-plant in the transplant trays, five days before planting out
Availability and legal status
Koppert, Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe rate is set by the damage, not by the efficacy. Every rate tested controlled the whitefly, but only 0.5 per plant did not increase crop damage.

Sources: 25 26 27

Ladybirds

Five species with very different thermal profiles, and the difference is decisive for Greece. Adalia bipunctata does not develop at all at 35 degrees [28], while Propylea quatuordecimpunctata has an upper threshold of 36.0 degrees and the lowest thermal constant of the group at 218 degree-days [30]. In a Greek July greenhouse that difference is the difference between a population and nothing.

Adalia bipunctata

Coccinellidae. Predatory beetle, ladybird

Aphids

Temperature
lower developmental threshold 10.06 degrees on aphid prey, thermal constant 267.9 degree-days, NO development at 35, optimum 23 to 27
Release rate
on trees, one bag per 25 centimetres of stem diameter, up to three per tree
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt lays eggs in clusters on the leaf underside, so they can be counted but also sprayed. It does not develop at all at 35 degrees, which in a Greek July greenhouse is a daily value.

Sources: 28 29

Propylea quatuordecimpunctata

Coccinellidae. Predatory beetle, ladybird

Aphids

Temperature
lower developmental threshold 10.2 degrees, thermal constant 218.0 degree-days, upper threshold 36.0, optimum 30.3
Release rate
no rate found, it is not widely sold as a commercial product
Availability and legal status
Andermatt. Not on the Greek National Catalogue of Macro-organisms; import proceeds through the EPPO PM 6/3 list.
The one thing that mattersIts thermal constant is the lowest and its upper threshold the highest of the three aphidophagous ladybirds, which makes it the heat-tolerant species. In Greece its role is mainly the conservation of native populations.

Sources: 30

Cryptolaemus montrouzieri

Coccinellidae. Predatory beetle

Mealybugs Armoured scales, secondary

Temperature
minimum activity 16 degrees, optimum 22 to 28, searching stops above 33 and all activity below 9
Relative humidity
optimum 70 to 80 percent
Release rate
adults 2 to 10 per square metre, larvae 5 to 40, repeated every one to two weeks
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe larva mimics a mealybug. Four characters separate them: waxy filaments on the BACK as well as the sides, twice the size of an adult mealybug, faster movement, and visible legs and mouthparts once the wax is brushed aside. A grower who cannot tell them apart sprays his own success.

Sources: 34 35

Nephus includens

Coccinellidae. Predatory beetle

Mealybugs

Temperature
lower developmental threshold 10.9 degrees, thermal constant 472.8 to 490.5 degree-days, no development at 10 or at 37.5
Release rate
no commercial release protocol was found
Availability and legal status
no supplier found among the three catalogues examined. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersMaximum fecundity at 25 degrees with 162.8 eggs, but maximum rate of population increase at 30. The foundational work is Greek, from the Benaki Institute, yet no commercial product was located.

Sources: 31 32

Rodolia cardinalis

Coccinellidae. Predatory beetle

Icerya purchasi (cottony cushion scale)

Temperature
lower developmental threshold 10.8 degrees, thermal constant 279 degree-days. At 34 eggs per female fall to 9.3 and at 37 none hatch
Release rate
not sold by the unit, it is already established throughout the Mediterranean
Availability and legal status
Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt completes 8 to 12 generations a year while Icerya completes only 3 to 4. That asymmetry, not any particular voracity, explains its historical success. The only decision that matters is not to spray it out.

Sources: 33

Other predatory insects

Atheta coriaria (Dalotia coriaria)

Staphylinidae. Soil-dwelling predatory beetle

Sciarid flies and thrips pupae in the substrate Thrips

Temperature
egg to adult 17.0 days at 26 degrees and 21 days at 21
Relative humidity
tolerates 40 to 99 percent
Release rate
1 to 5 per 0.93 square metres, or 100 to 1,000 per greenhouse, weekly to fortnightly
Availability and legal status
Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt eats the thrips pupae in the substrate, where no canopy predator reaches. It is not combined with Stratiolaelaps, because it eats it.

Sources: 12 36

Chrysoperla carnea

Chrysopidae. Green lacewing, predatory neuropteran

Aphids Whiteflies, secondary Spider mites, secondary Thrips, secondary Mealybugs, secondary

Temperature
minimum average 12 degrees, optimum 20 to 28. For the related C. agilis the developmental threshold is 11.4 to 11.8
Release rate
no single per square metre rate was given, the producer adjusts by crop
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersONLY the larva is predatory. The adult feeds exclusively on pollen, nectar and honeydew, and most adults leave the greenhouse. One larva eats 300 to 400 aphids. On hairy leaves performance drops markedly.

Sources: 85 86 87 88 89

Aphidoletes aphidimyza

Cecidomyiidae. Predatory gall midge

Aphids

Temperature
optimum 20 to 30 degrees, minimum night temperature 12 for oviposition
Relative humidity
above 70 percent
Release rate
1 to 10 per square metre per release, weekly
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersTwo independent reasons for failure. First, the larva drops to the ground to pupate and without one or two centimetres of moist medium the generation does not close. Second, at 9 hours of light 100 percent of larvae enter diapause, and in Greece the day falls below 15.5 hours from early August.

Sources: 83

Feltiella acarisuga

Cecidomyiidae. Predatory gall midge, spider mite specialist

Spider mites

Temperature
optimum 20 to 27 degrees
Relative humidity
above 80 percent, the most demanding species in this list
Release rate
0.25 to 25 per square metre, at least three times at weekly intervals
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersPhotoperiod on its own does NOT induce diapause, from 16 down to 8 hours, so unlike Aphidoletes it works through almost the whole growing season. The limiting factor is humidity. It also eats diapausing spider mites.

Sources: 84

Franklinothrips vespiformis

Aeolothripidae. Predatory thrips

Thrips Leafminers (Liriomyza), secondary Whiteflies, secondary Spider mites, secondary

Temperature
no published biology was located for the species
Release rate
no published rate was found
Availability and legal status
Andermatt. Not on the Greek National Catalogue of Macro-organisms; import proceeds through the EPPO PM 6/3 list.
The one thing that mattersIt is NOT on the Greek National Catalogue of Macro-organisms, but it is in Appendix 1 of EPPO PM 6/3. It can therefore be imported into Greece lawfully through the EPPO route.

Sources: 73 74

A contrast worth noting

Aphidoletes aphidimyza and Feltiella acarisuga are both gall midges and in both only the larva is predatory. Yet they behave in opposite ways in autumn. In Aphidoletes, nine hours of light induce diapause in 100 percent of larvae when the night is dark [83]. In Feltiella, photoperiod alone across the whole range from sixteen to eight hours induces no diapause at all [84]. One therefore shuts down in August and the other works through almost the entire growing season. The limiting factor for Feltiella is not daylength but humidity, which must exceed 80 percent [90].

Sources: 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 82 83 84 85 86 87 88 89 90 91 92 94

7. Parasitoid wasps

Ten species, and three concepts a grower needs in order to use them correctly.

Koinobiont or idiobiont

A koinobiont leaves the host alive and active after oviposition. An aphid that has received an Aphidius egg keeps feeding, and if it is fourth instar or adult it keeps reproducing for two more days [90]. An idiobiont paralyses the host on the spot. Aphytis melinus injects venom that permanently arrests development of the scale [47], and Diglyphus isaea paralyses the larva inside the mine and lays beside it [50]. The difference is that in the first case damage continues for days and in the second it stops at once.

Host feeding

Many females puncture hosts and drink their fluids without laying. Those hosts die but never become mummies, so mummy counts understate the real control. In Encarsia formosa a female parasitises about five whiteflies a day and eats another three [45], so roughly a third of the kills never show up in the mummy count. In Aphytis melinus host feeding and mutilation at times kill as many scales as parasitism does [47].

There is also a case where the commercial account does not hold. Aphelinus abdominalis is often said to kill more aphids by feeding than by parasitism. In a controlled study, host-feeding mortality was under 6 percent, against 54 to 60 percent successful parasitism [43].

The mummy, that is what the grower actually counts

An Aphidius mummy is golden-brown, hard and puffy, forming 7 to 12 days after oviposition, with the adult emerging another 4 to 6 days later through a round hole at the rear. An Aphelinus mummy is black and elongate, clearly less swollen [90]. In Encarsia formosa a parasitised Trialeurodes pupa turns black while a Bemisia pupa turns brown, and the round exit hole distinguishes it from the T-shaped slit a whitefly leaves on normal emergence [45]. Diglyphus leaves no mummy at all: the mature larva leaves six black pellets that hold the two leaf surfaces apart, and those are the equivalent of a mummy [50].

The practical conclusion is that a release is not assessed earlier than ten to fourteen days. Anyone who looks on day seven will see a failure that is not there.

Aphid parasitoids

The three Aphidius species divide the work by two criteria, aphid size and temperature. colemani is for small aphids and warm periods, ervi for large ones, and matricariae for early spring and the unheated greenhouse. Under identical conditions matricariae is consistently about two days slower than colemani, but with a cooler optimum [37]. Aphelinus abdominalis covers the upper end, performing better than the Aphidius species above 28 degrees [90].

Hyperparasitism, the most underestimated risk

In commercial greenhouses using banker plants, secondary parasitism of mummies was below 35 percent in February, above 40 in March and April, and above 70 percent in May and June, with the telling detail that in greenhouses where control failed the rise was significantly steeper [41]. In Belgium hyperparasitism reached 42 percent in sweet pepper [42]. A mummy with an irregular or lateral exit hole, rather than the neat round one at the rear, has produced a hyperparasitoid and not a beneficial.

Aphidius colemani

Braconidae. Endoparasitoid wasp, koinobiont

Aphids not on tomato

Temperature
egg to adult 10.0 days at 25 degrees, developmental threshold 2.97. Optimum 20 to 25, reduced above 30
Release rate
0.25 to 4 per square metre, at least three times
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe aphid does not die at once. It keeps feeding, and if it is fourth instar or adult it keeps reproducing for two more days. The mummy appears 7 to 12 days later, so an assessment made earlier shows a failure that is not real. On tomato the glandular trichomes cut parasitism roughly tenfold.

Sources: 37 40 41 42

Aphidius ervi

Braconidae. Endoparasitoid wasp, koinobiont

Aphids not on tomato

Temperature
oviposition to adult 12.1 days at 25 degrees and 25.0 at 15. Threshold 5.98, thermal constant 229.73 degree-days
Release rate
0.25 to 2 per square metre, weekly, preventively from planting
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThis is the species for the LARGE aphids. Females fed sugar live eight times longer than those given only water, and they need at least two feeds a day. A sugar source inside the crop is not decoration.

Sources: 38 39

Aphidius matricariae

Braconidae. Endoparasitoid wasp, koinobiont

Aphids not on tomato

Temperature
egg to adult 11.9 days at 25 degrees, threshold 3.37. Optimum 15 to 25, reduced above 28
Release rate
0.25 to 4 per square metre, at least three times
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersTwo days slower than colemani under identical conditions, but with a cooler optimum. It is the choice for early spring and the unheated greenhouse, while colemani is the choice for the warm period.

Sources: 37

Aphelinus abdominalis

Aphelinidae. Endoparasitoid wasp

Aphids

Temperature
effective 15 to 35 degrees, performs better than the Aphidius species above 28
Release rate
0.25 to 4 per square metre, particularly on hotspots
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe mummy is BLACK and elongate, not golden-brown and puffy like those of Aphidius. In the field that is the character that tells which parasitoid is working. The commercial claim that it kills more aphids by host feeding than by parasitism is not supported: in a controlled study host-feeding mortality was under 6 percent.

Sources: 43

Whitefly parasitoids

The choice between the two is purely thermal and there is a number for it. The developmental threshold of Eretmocerus eremicus is 13.0 degrees, the highest of the aphelinids, while that of Encarsia formosa is 8.1 to 11.5 depending on strain. At 15 degrees Eretmocerus needs 79.3 days and Encarsia 48. At 32 degrees both converge on 14 days [46]. Encarsia is therefore the cool choice and Eretmocerus the warm one, and that is a measured quantity rather than commercial positioning.

Encarsia formosa

Aphelinidae. Endoparasitoid wasp, thelytokous

Whiteflies

Temperature
optimum 20 to 25 degrees, insufficient when the 24-hour average falls below 17. It needs at least a 12-hour photoperiod
Relative humidity
50 to 80 percent
Release rate
1 to 10 per square metre, preventively, until control is achieved
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersBeyond the roughly 5 whiteflies parasitised per day it eats another 3, which die without ever becoming mummies. Mummy counts therefore understate the real control by about a third. A black pupa with a ROUND exit hole is a success, a transparent one with a T-shaped slit is a whitefly that emerged normally.

Sources: 44 45

Eretmocerus eremicus

Aphelinidae. Parasitoid wasp, first ecto then endo

Whiteflies

Temperature
lower developmental threshold 13.0 degrees, the highest of the aphelinids. It needs at least 20 and stays active above 30
Release rate
1 to 10 per square metre, at least three times at weekly intervals
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt lays the egg UNDERNEATH the whitefly nymph and the young larva penetrates later. Its reproduction is front-loaded into the first days of adult life, so the product is released fresh. At 15 degrees it needs 79.3 days while Encarsia needs 48, which is why Encarsia is the cool choice and Eretmocerus the warm one.

Sources: 46

Scale and mealybug parasitoids

Mind the name

Anagyrus vladimiri was formally described only in 2019. All earlier literature and much of the labelling use the names Anagyrus pseudococci or Anagyrus sp. near pseudococci, and refer to the same insect [48]. True A. pseudococci remains a valid but different species. The Greek national catalogue still carries the entry under the older name [75].

Aphytis melinus

Aphelinidae. Ectoparasitoid wasp, idiobiont

Armoured scales

Temperature
lower developmental threshold 9.7 degrees, upper threshold 30.0, thermal constant 226.5 degree-days
Release rate
In orchards converting to IPM, 100,000 per acre per year, roughly 247,000 per hectare, with individual releases of 5,000 to 10,000 per acre every two weeks. In coastal areas 10,000 to 40,000 per acre per year
Availability and legal status
no supplier found among the three catalogues examined. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe female drills through the scale cover and injects venom that permanently ARRESTS the host. Damage stops at the moment of attack, not days later. It prefers third-instar virgin females, so releases are timed just before a male flight. Host feeding at times kills as many scales as parasitism does.

Sources: 47

Anagyrus vladimiri

Encyrtidae. Endoparasitoid wasp

Mealybugs

Temperature
viable 14 to 34 degrees, optimum about 25, ceases at 35 and lethal at 40. At 14 it needs 79.3 days and at 34 only 10.5
Release rate
0.1 to 0.5 per square metre, at least three times at one to two week intervals
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersThe species was described in 2019. Everything published earlier as Anagyrus pseudococci or Anagyrus sp. near pseudococci refers to this insect, and both names appear on labels. ADULT female mealybugs yield the most offspring and the most female-biased sex ratio, while the producer advises targeting the third instar.

Sources: 48 49

Leafminer and egg parasitoids

Trichogramma achaeae is the only agent in this whole list that kills the pest before any damage occurs, because it attacks the egg. That carries a cost: the release must be synchronised with moth oviposition rather than with the calendar, because as the host egg ages the chorion hardens and parasitism falls clearly [55]. Standard practice in trials is eggs younger than twenty-four hours, which is why the published protocol is two releases a week and not one [53].

Trichogramma does not establish

Parasitoids developing on Tuta absoluta in tomato emerge with lower parasitism rates, wing deformations and shorter lifespans, and that generation contributes little to control [54]. In practice the control comes almost entirely from the released individuals and not from their offspring. Repetition is not optional, it is how the method works, and this is consistently missing from commercial material.

Diglyphus isaea

Eulophidae. Ectoparasitoid wasp, idiobiont

Leafminers (Liriomyza)

Temperature
egg to adult about 10 days at 25 degrees and 27 at 15. Thermal constant 161.8 degree-days above 9.2
Release rate
0.25 to 3 per square metre, at least three times at weekly intervals
Availability and legal status
Koppert. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt permanently paralyses the larva inside the mine and lays BESIDE it, not inside it. The mine stops growing at that moment. It leaves no mummy, but the mature larva leaves six black pellets that hold the leaf surfaces apart, and those are what the grower counts.

Sources: 50 51

Trichogramma achaeae

Trichogrammatidae. Egg parasitoid wasp

Lepidopteran eggs (codling moth and others) Tuta absoluta

Temperature
lower developmental threshold 10.51 degrees, thermal constant 138.27 degree-days. Net reproductive rate peaks at 20, no viable progeny at 35
Release rate
Eight releases of 50 adults per square metre, twice weekly, gave 85.63 percent parasitism in an early infestation. One release of 100 per square metre under high pressure gave 91.03 percent
Availability and legal status
Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt is the only agent here that kills the pest BEFORE any damage occurs, because it attacks the egg. Parasitism falls clearly as the host egg ages and the chorion hardens, so releases track moth oviposition rather than the calendar. It does not establish: offspring developing on Tuta in tomato contribute little, so repetition is compulsory.

Sources: 52 53 54 55 93

Sources: 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 75 90 93

8. Entomopathogenic nematodes

Three species, and the choice between them is governed not by the pest but by two other things: soil temperature and foraging strategy.

Ambusher or cruiser

Steinernema carpocapsae is an ambusher. It stands upright on its tail near the soil surface and attaches to passing hosts. It therefore reaches mobile, surface-active insects, the caterpillars, crickets and borers, and almost never reaches the sedentary larvae of the deeper soil. Heterorhabditis bacteriophora is a cruiser. It moves actively through the medium and finds exactly those sedentary root feeders that the ambusher never meets. It is also the only one of the three that bores directly through the host cuticle with a dorsal tooth rather than entering only through natural openings. Steinernema feltiae sits between the two.

The temperature window, which is the single most useful fact here

S. feltiae infects and establishes from 8 to 30 degrees and reproduces from 10 to 25, while S. carpocapsae reproduces from 20 to 30 [56]. In strictly practical terms: in an autumn application against overwintering codling moth larvae, S. feltiae gave 90 percent mortality in October while S. carpocapsae gave only 58 [58]. At 10 degrees carpocapsae kills nothing at all [59]. feltiae is the cold species, carpocapsae the warm one, and bacteriophora loses performance below 20.

Why only one of the three goes on foliage

At 85 percent relative humidity, S. feltiae and H. bacteriophora die completely within two hours, while more than 80 percent of S. carpocapsae survive [60]. Ultraviolet radiation compounds this: direct sunlight reduced pathogenicity by 6.9 percent at thirty minutes and by 94.9 percent at sixty [61]. Application is therefore always in the late afternoon or evening, with spray water below 25 degrees, pH between 4 and 8, no filters finer than 0.3 millimetres and nozzles of at least 0.5 millimetres [90].

Steinernema feltiae

Steinernematidae. Entomopathogenic nematode, symbiont Xenorhabdus bovienii

Sciarid flies and thrips pupae in the substrate Overwintering codling moth larvae in the soil Thrips Leafminers (Liriomyza) Capnodis (stone fruit flatheaded borer) Tuta absoluta, secondary

Temperature
Infection and establishment 8 to 30 degrees, reproduction 10 to 25. No infectivity at 30, no progeny at 28. Host death in 12 days at 8 degrees and 2 days at 25
Relative humidity
moist but not saturated substrate
Release rate
250,000 to 500,000 infective juveniles per square metre in soil, 1 to 3 million per litre for foliar application
Availability and legal status
Koppert, Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt is the COLD species, the only one of the three that infects reliably below 12 degrees. In an autumn application against overwintering codling moth larvae it gave 90 percent in October while carpocapsae gave only 58.

Sources: 56 57 58 64 65

Steinernema carpocapsae

Steinernematidae. Entomopathogenic nematode, symbiont Xenorhabdus nematophila

Red palm weevil Capnodis (stone fruit flatheaded borer) Overwintering codling moth larvae in the soil Lepidopteran eggs (codling moth and others) Tuta absoluta

Temperature
Reproduction 20 to 30 degrees, most effective 22 to 28. At 10 degrees it causes no codling moth mortality at all
Relative humidity
needs wetting, but it is the most desiccation-tolerant of the three
Release rate
In soil at the same orders of magnitude. For palms 5 to 20 litres per palm, or 1 million juveniles per litre of spray
Availability and legal status
Koppert, Bio-Insecta, Andermatt. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt is the AMBUSHER. It stands on its tail near the surface and attaches to passing hosts, so it reaches mobile surface-active insects and not the sedentary larvae of the deeper soil. At 85 percent relative humidity more than 80 percent survive two hours, while the other two species die completely.

Sources: 56 59 60 61 66

Heterorhabditis bacteriophora

Heterorhabditidae. Entomopathogenic nematode, symbiont Photorhabdus

Vine weevils and root-feeding chafer grubs Capnodis (stone fruit flatheaded borer) Sciarid flies and thrips pupae in the substrate, secondary Tuta absoluta, secondary

Temperature
Active 16 to 35 degrees according to the producer, optimum 19 to 33. Performance falls below 20
Relative humidity
soil only, it does not tolerate desiccation
Release rate
250,000 to 500,000 infective juveniles per square metre
Availability and legal status
Koppert, Bio-Insecta. Listed on the Greek National Catalogue of Macro-organisms.
The one thing that mattersIt is the CRUISER and the only one of the three that bores directly through the host cuticle with a dorsal tooth. It moves actively through the medium and reaches the sedentary root-feeding larvae the ambusher never encounters. At 85 percent humidity it dies completely within two hours, so never foliar.

Sources: 56 60 62 63

The growing medium matters more than is usually suspected. Across seven soils, infectivity of H. bacteriophora was highest in potting medium and lowest in acidic sand, while its persistence was shortest precisely where infectivity was greatest. The authors warn explicitly against generalising soil effects from one species to another [62].

Sources: 56 57 58 59 60 61 62 63 64 65 66 72 90

9. Full table of species, products and suppliers

The table brings together all thirty-seven species. Suppliers are taken from the catalogues of Koppert Greece, Bio-Insecta and Andermatt Hellas as they stood in September 2026. The catalogue column shows whether the species appears on the Greek National Catalogue of Macro-organisms [75]. The search filters scientific name, family, target and supplier at the same time.

SpeciesGroupFamilyMain targetsSuppliersGreek national list
Amblydromalus limonicusCanopy predatory mitePhytoseiidaeThrips, WhitefliesKoppertYes
Amblyseius andersoniCanopy predatory mitePhytoseiidaeEriophyid and tarsonemid mites, Spider mitesBio-Insecta, AndermattYes
Amblyseius swirskiiCanopy predatory mitePhytoseiidaeThrips, Whiteflies, Eriophyid and tarsonemid mitesKoppert, Bio-Insecta, AndermattYes
Neoseiulus californicusCanopy predatory mitePhytoseiidaeSpider mites, Eriophyid and tarsonemid mitesKoppert, Bio-Insecta, AndermattYes
Neoseiulus cucumerisCanopy predatory mitePhytoseiidaeThrips, Eriophyid and tarsonemid mitesKoppert, Bio-InsectaYes
Phytoseiulus persimilisCanopy predatory mitePhytoseiidaeSpider mitesKoppert, Bio-Insecta, AndermattYes
Transeius montdorensisCanopy predatory mitePhytoseiidaeThrips, WhitefliesKoppertYes
Macrocheles robustulusSoil predatory miteMacrochelidaeSciarid flies and thrips pupae in the substrate, ThripsKoppertYes
Stratiolaelaps scimitusSoil predatory miteLaelapidaeSciarid flies and thrips pupae in the substrateKoppert, Bio-InsectaYes
Adalia bipunctataPredatory insectCoccinellidaeAphidsKoppert, Bio-InsectaYes
Anthocoris nemoralisPredatory insectAnthocoridaePear and olive psyllidsBio-Insecta, AndermattYes
Aphidoletes aphidimyzaPredatory insectCecidomyiidaeAphidsKoppert, Bio-InsectaYes
Atheta coriaria (Dalotia coriaria)Predatory insectStaphylinidaeSciarid flies and thrips pupae in the substrate, ThripsAndermattYes
Chrysoperla carneaPredatory insectChrysopidaeAphidsKoppert, Bio-InsectaYes
Cryptolaemus montrouzieriPredatory insectCoccinellidaeMealybugsKoppert, Bio-InsectaYes
Feltiella acarisugaPredatory insectCecidomyiidaeSpider mitesKoppertYes
Franklinothrips vespiformisPredatory insectAeolothripidaeThripsAndermattNo, via EPPO PM 6/3
Macrolophus pygmaeusPredatory insectMiridaeWhiteflies, Tuta absolutaBio-InsectaYes
Nephus includensPredatory insectCoccinellidaeMealybugsnone of the threeYes
Nesidiocoris tenuisPredatory insectMiridaeTuta absoluta, WhitefliesKoppert, Bio-Insecta, AndermattYes
Orius laevigatusPredatory insectAnthocoridaeThripsBio-Insecta, AndermattYes
Orius majusculusPredatory insectAnthocoridaeThripsBio-InsectaYes
Propylea quatuordecimpunctataPredatory insectCoccinellidaeAphidsAndermattNo, via EPPO PM 6/3
Rodolia cardinalisPredatory insectCoccinellidaeIcerya purchasi (cottony cushion scale)Bio-InsectaYes
Anagyrus vladimiriParasitoid waspEncyrtidaeMealybugsKoppertYes
Aphelinus abdominalisParasitoid waspAphelinidaeAphidsKoppertYes
Aphidius colemaniParasitoid waspBraconidaeAphidsKoppert, Bio-InsectaYes
Aphidius erviParasitoid waspBraconidaeAphidsKoppert, Bio-InsectaYes
Aphidius matricariaeParasitoid waspBraconidaeAphidsKoppertYes
Aphytis melinusParasitoid waspAphelinidaeArmoured scalesnone of the threeYes
Diglyphus isaeaParasitoid waspEulophidaeLeafminers (Liriomyza)KoppertYes
Encarsia formosaParasitoid waspAphelinidaeWhitefliesKoppertYes
Eretmocerus eremicusParasitoid waspAphelinidaeWhitefliesKoppert, Bio-InsectaYes
Trichogramma achaeaeParasitoid waspTrichogrammatidaeLepidopteran eggs (codling moth and others), Tuta absolutaAndermattYes
Heterorhabditis bacteriophoraEntomopathogenic nematodeHeterorhabditidaeVine weevils and root-feeding chafer grubs, Capnodis (stone fruit flatheaded borer)Koppert, Bio-InsectaYes
Steinernema carpocapsaeEntomopathogenic nematodeSteinernematidaeRed palm weevil, Capnodis (stone fruit flatheaded borer), Overwintering codling moth larvae in the soil, Lepidopteran eggs (codling moth and others), Tuta absolutaKoppert, Bio-Insecta, AndermattYes
Steinernema feltiaeEntomopathogenic nematodeSteinernematidaeSciarid flies and thrips pupae in the substrate, Overwintering codling moth larvae in the soil, Thrips, Leafminers (Liriomyza), Capnodis (stone fruit flatheaded borer)Koppert, Bio-Insecta, AndermattYes

Sources: 73 75 90

10. Release rates and timing

Most circulating rates come from producer technical sheets. There are however six cases where the rate has been measured in peer-reviewed work, and those deserve separate treatment because in two of them the result was the opposite of the commercial advice.

SpeciesRateWhat it showedSource type
Orius laevigatus2 individuals per square metreThrips control statistically identical to 6 per square metre, with no difference in the quantity or quality of the sweet pepper crop. The reduced rate maintains effective control.Peer-reviewed [18]
Nesidiocoris tenuis0.5 individuals per plant, pre-plantEvery rate controlled the whitefly. Only this one did not increase crop damage. The rate is set by the damage, not by the efficacy.Peer-reviewed [26]
Nesidiocoris tenuis1 individual per 2 plants in the trays, 5 days before planting outPopulation fell in weeks 1 to 3 then stabilised above 2 per leaf from week five. Fruit damage fell from over 90 percent to about 5.Peer-reviewed [27]
Trichogramma achaeae8 releases of 50 per square metre, twice weekly85.63 percent parasitism in an early infestation with discrete generations.Peer-reviewed [53]
Trichogramma achaeae1 release of 100 per square metre91.03 percent parasitism under high pest incidence.Peer-reviewed [53]
Aphytis melinus5,000 to 10,000 per acre every two weeksSeasonal split of 50 percent in the critical spring period, 25 percent summer, 25 percent autumn. Releases stop when suitable scale stages are unavailable.University extension [47]
Steinernema feltiae250,000 to 500,000 per square metre in soilSciarid numbers fell significantly within this range, but the outcome depended decisively on the growing medium.Peer-reviewed [65]
Steinernema carpocapsae1 to 1.5 million per tree75 to 90 percent control of Capnodis in apricot. The spring application precedes egg laying.Peer-reviewed [66]
Timing, in four rules
  • By pest stage, not by the calendar. Aphytis needs third-instar virgin female scales [47]. Diglyphus needs second and third instar leafminer larvae inside the mine [50]. Trichogramma needs eggs younger than twenty-four hours [55]. A release made against the wrong stage is money thrown away, not merely reduced performance.
  • Preventive for generalists, curative for specialists. A Type III phytoseiid is established before the pest appears, on pollen. A Type I goes in only when spider mites are already there [1].
  • Pre-plant where the evidence supports it. Nesidiocoris and Macrolophus establish better when introduced into the transplant trays or onto banker plants before planting out [27].
  • In groups, not scattered. The Orius producer asks for groups of at least fifty individuals [90], and the corresponding work on Macrolophus shows that below a threshold founder population establishment simply fails [91].

Sources: 1 18 26 27 47 50 53 55 65 66 90 91 92

11. Compatibility with plant protection products

A single spray can cancel an entire release programme, and what matters is not only whether it kills but for how long it stays dangerous. The international rating system is that of the IOBC, which places each product in one of four classes [68]. There is a trap here that appears often in the literature: the class boundaries differ between laboratory and field, and they are not interchangeable.

ClassRatingLaboratorySemi-field and field
1Harmlessbelow 30 percentbelow 25 percent
2Slightly harmful30 to 79 percent25 to 50 percent
3Moderately harmful80 to 99 percent51 to 75 percent
4Harmfulabove 99 percentabove 75 percent

The reason for the difference is that the laboratory test uses a fresh dry residue on glass, that is the worst possible exposure, so a product must be nearly inert to be rated harmless. In the field exposure is realistic and the threshold tightens.

What is measured is not mortality

The scheme rates the reduction in beneficial capacity, that is mortality together with sublethal effects on fecundity and searching behaviour [68]. That is why a product can be rated moderately harmful to Aphidius colemani on only 11.4 percent mortality at twenty-four hours [70]. A parasitoid that survives but cannot orient to host odours contributes nothing, and that is precisely the distinction between acute toxicity and a sublethal effect [67].

Persistence, which often matters more than the class

In trials on Aphytis melinus in citrus, most of the harmful products lost their negative effect somewhere between one and six weeks. Lambda-cyhalothrin remained harmful eleven weeks after application [71]. A single pyrethroid application is therefore enough to cancel a whole season of releases, however well everything else was done.

Which products are dangerous and which are not

In laboratory IOBC assessment on adult Amblyseius swirskii, sulfoxaflor, flonicamid, flubendiamide, metaflumizone, methoxyfenozide, spiromesifen and spirotetramat were rated harmless, while abamectin, deltamethrin and spinosad were rated harmful [69]. In corresponding work on three other beneficials, pyridaben, acetamiprid, spinosad and propargite were harmful to Aphidius colemani and Aphidoletes aphidimyza, while Neoseiulus cucumeris was clearly the least sensitive of the three [70].

Three precautions before using any such list
  • The rating changes by beneficial and by stage. What is harmless to N. cucumeris may be harmful to P. persimilis [70].
  • Part of the older literature concerns substances that no longer exist. The approval of chlorpyrifos has been withdrawn in the Union. Every list must be cross-checked against the live authorisation database before use.
  • The same applies to nematodes. Spiromesifen and spinosad left survival of H. bacteriophora intact but significantly reduced its reproduction [72]. Sublethal effects are not the preserve of arthropods.

Sources: 67 68 69 70 71 72 90

12. Eight documented ways a release fails

Each of the following has been measured and published. None is speculation.

1. The air is too dry for the eggs

In Phytoseiulus persimilis, at 60 percent relative humidity fewer than 20 percent of eggs hatch, while at 85 percent almost all do. The midpoint is 66.8 percent, that is a vapour pressure deficit of 1.05 kPa. More importantly, five commercial strains proved genetically identical in this respect, so there is no more tolerant strain to buy. In Amblyseius swirskii the corresponding desiccation limit is 40 percent. [3] [2]

2. Two generalist predators together

The four generalist phytoseiids each independently carry a warning against combining them. The same phenomenon has been measured in insects: Cryptolaemus montrouzieri and Chrysoperla carnea eat one another, usually in favour of the lacewing, and the conflict is reduced only when abundant alternative prey is present. The same applies to Dalotia coriaria, which eats Stratiolaelaps scimitus. [90] [82] [12]

3. Success creates the damage

In Nesidiocoris tenuis yield reduction appears after the predator population has peaked and after the whitefly has already been reduced. The predator to prey ratio passes 0.168 and a well-fed, established population turns on the plant. [25]

4. The larva finds nowhere to pupate

Aphidoletes aphidimyza drops to the ground and burrows one or two centimetres into moist medium or organic debris to spin a cocoon. On a concrete or clean plastic floor the generation never closes and the population never establishes, however many individuals are released. [83] [90]

5. Photoperiod stops reproduction

In the southern strain of Orius majusculus, from Antalya at the latitude of the Peloponnese, 11.5 hours of light induce diapause in 100 percent of females and 12 hours in 25 percent. The northern strain needs 14 to 16 hours. And once established, diapause is not terminated within fourteen days even when temperature and daylength are raised, so supplementary lighting must be preventive rather than curative. [19] [20]

6. The crop leaf does not allow it

The glandular trichomes of tomato do not merely impede phytoseiid movement, they are toxic to nymphs and adults. The same phenomenon affects parasitoids: on plants with glandular trichomes the number of aphids parasitised by Aphidius colemani fell roughly tenfold, and only 5.6 percent of mortality was attributable to parasitism. [2] [40]

7. Hyperparasitism consumes the parasitoid

In commercial greenhouses secondary parasitism of mummies exceeded 70 percent in May and June, and in sweet pepper in Belgium it reached 42 percent. A mummy with an irregular exit hole did not produce a beneficial, it produced a hyperparasitoid. [41] [42]

8. The grower sprays his own success

The larva of Cryptolaemus montrouzieri resembles a mealybug so closely that a large predator population reads as a worsening infestation. The spray that follows kills the exposed predators, while the real mealybugs, concealed under wax in leaf axils and bark crevices, survive better. The field test takes one finger: brush the wax aside and legs and mouthparts appear. [34]

Sources: 2 3 12 19 20 25 34 40 41 42 82 83 90

13. What changes under Greek conditions

Nearly all technical sheets and a large part of the trial work come from the Netherlands, Belgium and Britain. Four parameters do not transfer unchanged.

Photoperiod, which is the most serious

The critical photoperiod depends on the latitude the strain came from, and the difference is very large. The southern strain of Orius majusculus from Antalya, at 37.0 degrees north and therefore at the same latitude as the Peloponnese and Crete, stays reproductively active on just 12 hours of light, while the northern strain needs 14 to 16 [19]. A northern strain released into a Greek autumn greenhouse meets days well below its own threshold and stops laying. The same applies to Aphidoletes aphidimyza, which enters diapause below fifteen and a half hours, a threshold crossed in Greece from early August [83].

There is a remedy and it is cheap: low-intensity night lighting. For Orius majusculus 10 lux suffices [19], while for Aphidoletes radiation below 5.5 lux does not [83]. It must however be preventive, because once diapause is established it does not break easily [20].

Two species do not have this problem and deserve preference in autumn plantings. Macrolophus pygmaeus at ten hours of light merely slows by one or two days, with no reproductive diapause, and the Rome strain matures faster than the Sochi one [23]. Feltiella acarisuga does not enter photoperiodic diapause at all [84].

Summer temperature

Values that are extreme in northern Europe are simply July in Greece. Adalia bipunctata does not develop at all at 35 degrees [28]. In Rodolia cardinalis eggs per female fall to 9.3 at 34 degrees and hatch fails completely at 37 [33], while the adults survive, so a midsummer reproductive pause is to be expected in Greek citrus in July and August. In Neoseiulus californicus females still oviposit at 37.5 degrees but no eggs hatch [5]. By contrast Propylea quatuordecimpunctata with an upper threshold of 36.0 degrees [30] and Amblyseius swirskii with a population growth optimum of 30.1 [4] are built for these conditions.

Humidity

This is the most underestimated constraint in Greece, and the only species with a genuine dose response curve is Phytoseiulus persimilis [3]. For the rest there are only qualitative producer statements: above 70 percent for cucumeris, above 65 for andersoni, above 60 for montdorensis, and above 80 for Feltiella [90]. In a Greek summer greenhouse and outdoors, those thresholds are not a given.

What is already here

Two observations that change the economics. Amblyseius swirskii is native to the eastern Mediterranean, with Greece among its countries of origin [73], so releasing it is not the introduction of a foreign organism. Rodolia cardinalis is already established throughout the Mediterranean and is not sold by the unit, so the only decision that matters for it is not to spray it out [33]. And Amblyseius andersoni overwinters in the leaf litter and climbs into the canopy on its own, so in olive, grapevine and top fruit it can be conserved rather than bought each year [16].

Greek research underpinning this article

Not everything here is imported. The thermal thresholds of Macrolophus pygmaeus were measured at the Agricultural University of Athens [22]. The biology of Nephus includens, a predator of the citrus mealybug, and the thermal data for Propylea come from the Benaki Phytopathological Institute [31] [32] [30]. The work showing that Amblydromalus limonicus effectively does not reproduce on a spider mite diet was done at the Democritus University of Thrace [7], as was the work on green lacewing biology [85] [86] [88].

Sources: 3 4 5 7 16 19 20 22 23 28 30 31 32 33 73 83 84 85 86 88 90

14. Sources

Numbers in the text refer to the list below. Where a value comes from a producer technical sheet rather than from peer-reviewed work, this is stated explicitly in the text.

Disclaimer

The Greek plant protection authorisations and the national registration regime described here apply in Greece only. They confer no status in any other country. Readers outside Greece must consult their own national authority: the regulation of beneficial macro-organisms is not harmonised across the European Union and differs considerably between member states.

Beneficial macro-organisms are not plant protection products and carry no marketing authorisation number. Lawful supply in Greece requires registration of the preparation in the National Catalogue of Plant Protection Preparations containing Macro-organisms and listing of the species either on the National Catalogue of Macro-organisms or on EPPO Standard PM 6/3. That check rests with the user and the supplier.

The release rates given are indicative and do not constitute a recommendation to apply. They come either from peer-reviewed publications, where stated, or from producer technical sheets, and in every case depend on the crop, pest density, temperature, humidity and type of structure. The final rate and timing are set after an on-site assessment by a licensed agronomist.

Where plant protection products are mentioned, their use is governed exclusively by the authorisations in force in the country of use and by the product label. IOBC compatibility ratings apply to a specific beneficial species, a specific stage and specific test conditions, and do not generalise. Part of the older literature refers to active substances whose approval has since been withdrawn in the European Union, so every reference must be cross-checked against the current authorisation database before use.

The warning that applies to every article mentioning foliar sprays applies here too: spraying trees carrying fruit can cause fruit blemish and foliar scorch, a prior test on a limited number of trees with the same product at the same rate followed by five to seven days of observation is required before any general application, and spraying is done in the late afternoon or early morning, never in a heatwave and never on foliage under water stress.

Errors and omissions in the data behind the selection tool and the tables cannot be excluded. The percentage the tool returns is not a probability of success. Every intervention is at the user's own responsibility following an on-site assessment by a licensed agronomist. Pastopoulos Agronomics accepts no liability for the use of this information.

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