product specifications. Quality assurance, on
the other hand, looks at product quality from
a proactive viewpoint. The fundamental idea
is that, if the production process is well orga-
nized and of high quality, the result of the
production process should also be of high
quality. Already in the 1980s, Chambers and
Ashley (1984) and Leppla and Fisher (1989)
introduced the notion of total quality man-
agement for the production of natural ene-
mies. They made a distinction between
product control, production control and
process control. Product control rejects faulty
products, production control assures consis-
tency of production output for a given pro-
duction process and process control tells
how well a production process is performing
(see Chapter 2 for details).
To date these notions are still not widely
recognized by commercial producers of nat-
ural enemies. The establishment of a total
quality-management programme requires
substantial extra investments, which are lim-
ited for most commercial producers.
However, a more proactive approach to
product quality not only requires investment
in total quality-management techniques but
also requires a more profound knowledge of
those factors that influence product quality
during the production and logistic chain.
What is Optimal Quality?
Many researchers and also end-users have
the feeling that mass-reared natural enemies
should have the same quality as the original
collected field population. This is not only an
illusion: it is an unnecessary and expensive
goal to pursue (van Lenteren, 1991). Van
Lenteren and Tommasini (1999) state:
Rather than pursuing a scientific approach on
the development of quality control, we would
like to follow a more pragmatic way. The aim of
releases of mass produced natural enemies is to
control a pest. In this context the aim of quality
control should be to determine whether a
natural enemy is still in a condition to properly
control the pest. Formulated in this way we do
not deal with terms like maximal or optimal
quality, but something like acceptable quality.In the case of seasonal inoculative biological
control, it is mainly the descendants of the
introduced natural enemies that will control
the target pest. In the case of inundative
releases, the released individuals should be
able to reduce the pest population. The char-
acteristics to be measured should be limited
in number but directly linked to field perfor-
mance and determining whether the
released individuals are still of acceptable
quality. However, the currently applied
quality control techniques are still labour-
intensive and therefore expensive. The
development of accurate but less labour-
intensive techniques would allow more reg-
ular testing of product quality than
currently performed by many companies.Quality Assurance in Production
Many authors have discussed changes in
genetic variability and inbreeding during
mass rearing. Van Lenteren and Tommasini
(1999) give a recent overview. Although this
subject is still poorly understood by scien-
tists and producers, the recent evolution of
molecular techniques makes possible a
more profound insight into the influence of
mass-rearing conditions on the genetic vari-
ability over the coming years. However,
producers should already implement in a
pragmatic way guidelines for the minimum
size of founder populations, composition of
founder populations (collect from a wide
area with different climatic and ecological
characteristics), regular strain renewal or
alternatively gene infusion and maintaining
mother cultures under variable laboratory
environments. Valuable information can be
found in Joslyn (1984) and Chapters 1, 6
and 7.
Mass-rearing natural enemies in an eco-
nomic way resulting in biocontrol agents
that are affordable by the grower will
inevitably always be an ‘unnatural activity’.
However, the negative effects of
unfavourable rearing conditions, such as
food availability, overcrowding, unfavour-
able climatic conditions, etc., on the fitness
of the natural enemies and therefore on
product quality can be managed throughDevelopment of Quality Control in Europe 219