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facilities), Cuba (more than 200 facilities),
Mexico (30 facilities) and Peru (more than 20
facilities). For prices of natural enemies in
Europe and the USA, see van Lenteren et al.
(1997) and Cranshaw et al.(1996), respec-
tively.
Commercial natural-enemy producers rear
mainly predators and parasitoids (see Table
1.1). Only a few companies produce microbial
agents, such as nematodes, entomopatho-
genic fungi, bacteria or viruses. Chemical
companies are the main producers of micro-
bial agents and it is expected that all activities
in this area will in the future be exclusively
the domain of the pesticide industry. Mass-
rearing methods for parasitoids and predators
are usually developed on an ad hoc basis, an
approach that may result in natural enemies
of poor quality. The technology for rearing
natural enemies on ‘unnatural’ hosts and host
plants or on artificial diets is not yet well
developed (see Chapter 9) and seems to be
hampered not only by physiological problems
but also by ethological and ecological ones
(requirements for associative learning of host-
habitat and host-finding cues (see Chapters 3
and 4)). Conflicts between attributes favoured
in mass-rearing programmes and those
needed for field performance form another
obstacle for the cost-effective production of
natural enemies. Artificial selection that
occurs during mass rearing may lead to
reduced performance of natural enemies (see
below, and Chapters 6 and 7). The suggested
cures for this problem are often expensive and
time-consuming and are therefore very sel-
domly applied.
Professional natural-enemy producers
may have research facilities, procedures for
monitoring product quality, an international
distribution network, promotional activities
and an advisory service. The market for
high-quality, effective natural enemies will
certainly increase with the growing demand
for unsprayed food and a cleaner environ-
ment. The growing pesticide-resistance prob-
lems will also move growers to adopt
biological control methods.
Initial developments in the area of mass
production, quality control, storage, ship-
ment and release of natural enemies
(Chapter 12) have decreased production

costs and led to better product quality, but

much more can be done. Innovations in

long-term storage (e.g. through induction of

diapause), shipment and release methods

may lead to a further increase in natural-

enemy quality, with a concurrent reduction

in costs, thereby making biological control

easier and economically more attractive to

apply. Even if the natural enemies leave the

insectary in good condition, shipment and

handling by the producers, distributors and

growers may result in deterioration of the

biological control agents before they are

released.

Quality control programmes that address

not only natural-enemy numbers but also

natural-enemy quality (field performance)

are a necessity. Simple and reliable quality

control programmes for natural enemies are

now emerging as a result of intensive coop-

eration between researchers and the biologi-

cal control practitioners, and it is expected

that these developments will result in a

rapid improvement of the biological control

industry.

The International Organization for Biological

Control/European Community (IOBC/EC)

initiative on quality control

Although augmentative types of biological

control of arthropod pests have been applied

since 1926, large-scale production of natural

enemies began only after the Second World

War (DeBach, 1964; van Lenteren and Woets,

1988). Initial mass-rearing efforts involved

the production of not more than several

thousand individuals per week of three nat-

ural enemies: the spider-mite predator P. per-

similis, the whitefly parasitoid E. formosa

and the lepidopteran egg parasitoid

Trichogramma sp. None of the early publica-

tions on commercial aspects of biological

control mention the topic of quality control

of natural enemies (e.g. Hussey and

Bravenboer, 1971). Quality control is men-

tioned in relation to biological control only in

the mid-1980s, and shortly after that the

topic gained more interest (van Lenteren,

1986a,b). The Fifth Workshop of the IOBC

Global Working Group, ‘Quality Control of

Need for Quality Control of Biocontrol Agents 5