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their target hosts (for details, see van
Lenteren, 1986a, and Chapters 1 and 2).
Rearing conditions should be as similar as
possible to the conditions under which the
natural enemies will have to function in the
field or greenhouse. Two examples of mass-
production schemes, one for the predator
Oriusand the other for the parasitoid Encarsia,
are presented in Figs 12.1 and 12.2.

Storage of Natural Enemies

It is necessary to have storage methods and
facilities available to meet the requirements
for good planning for a mass-production

unit and because of the difficulty of accu-

rately predicting demand from clients (both

delivery dates and quantities). This is rela-

tively simple for microbial biocontrol

agents, such as fungi, viruses and bacteria,

because they can often be stored in a resting

stage for months or even years. Many preda-

tors and parasitoids can only be stored for a

short time. This usually involves placing the

natural enemies as immatures at tempera-

tures between 4 and 15°C. Normally, storage

only lasts several weeks, but even then

reduction in fitness is the rule (Posthuma-

Doodeman et al., 1996). Storage of para-

sitoids at a low temperature (8°C) for 2 and

16 days, respectively, gives similar percent-

Mass Production of Natural Enemies 183

Table 12.1.Commercial biological control of endemic or exotic arthropods with

endemic or exotic natural enemies in Europe (the numbers reflect the number of

combinations in which a certain natural enemy is used for control of a certain pest;

situation in 1999).

Different combinations of natural-enemy use in Europe

Use of endemic natural enemies for the control of endemic pests:

example:Chrysoperla carneafor control of endemic aphid species 61

Use of endemic natural enemies for the control of exotic pests:

example:Diglyphus isaeafor control of exotic Lyriomyzaspecies 40

Use of exotic natural enemies for the control of endemic pests:

example:Harmonia axyridisfor control of endemic aphid species 44

Use of exotic natural enemies for the control of exotic pests:

example:Encarsia formosafor control of exotic whitefly species 47

Put bean pods with Orius eggs

into cage with dispersal material

andEphestia eggs as prey

Harvesting of newly

emerged adults

Storage for a few days if

necessary

Collection and change of

bean pods, and addition of

food (2–3 times per week)

New prey is added

twice a week

Put adults into new

cage, supply with

prey and bean pods

Packaging and

shipment

Old adults are

eliminated

17 days

28 days

Fig. 12.1.Production scheme for the thrips predator Oriussp.