the establishment of well-specified rearing
protocols, rigorous production control and
quality measuring throughout the produc-
tion cycle. Preventing these problems
requires a good deal of knowledge, experi-
ence with mass rearing and ‘green fingers’.
Probably the least understood and least
studied factor that influences product qual-
ity is the effect of microbial contamination
by entomopathogenic fungi, bacteria,
viruses or microsporidia (Shapiro, 1984;
Sikorowski, 1984). Except for predatory
mites, very little is known about the impor-
tance of microbial diseases for parasitic
hymenopterous wasps, dipterous gall-
midges, hemipterous bugs and coccinellid
beetles. An overview of current knowledge
is given by Bjørnson and Schütte in Chapter
- As the knowledge in this field increases,
additional standard testing guidelines to
check for the presence of entomopathogens
could be developed.
A concern that has emerged more
recently is the risk of plant-disease trans-
mission, particularly viruses, by natural
enemies or their hosts that might acciden-
tally or intentionally be included in the
product. More specifically, the fear of
Pepino mosaic virus (PepMV) by European
tomato growers has led several producers
of natural enemies to investigate the poten-
tial of vectoring plant viruses by natural
enemies, such as Macrolophus caliginosus. We
believe that strict hygienic production pro-
cedures, adapted rearing facilities, choice of
plants that are not hosts for such dangerous
plant viruses, routine checks for plant
viruses and occasional inspections by local
plant-protection services are the best way to
ensure a clean product. As a general rule,
plant material should be avoided as much
as possible in the final product. If it is neces-
sary to include some plant material to
assure optimal product quality and sur-
vival, it should be free from plant diseases
and the plant material should, when the
natural enemies are released, not come in
direct contact with the crop.
All biocontrol products should in princi-
ple be pure and free from contamination by
potential pests. However, the presence of a
limited number of the target host, such as
whiteflies in the case of whitefly parasitoids
or spider mites in the case of spider-mite
predators, can often not be avoided and
should also not necessarily be a problem, on
the condition that they do not provide a risk
for transmission of plant diseases or creat-
ing a pest.
Taxonomy is a crucial element in the qual-
ity assurance of beneficial arthropods.
Insectaries should have established proce-
dures to verify the identity of the natural
enemies produced. Although a shortage of
taxonomists places severe limitations on
authoritative identification of some hard-to-
identify organisms, such as Trichogramma
spp., every reasonable effort should be made
to use available resources to obtain proper
identification (Penn et al., 1998).Harvesting and Formulating
Harvesting and formulation techniques can
have a large impact on product quality due
to their technical nature and the intensive
mechanical handling of the mass-reared
natural enemies. All producers have devel-
oped their own, proprietary techniques for
harvesting, purifying, counting and formu-
lating natural enemies. The nature of the
applied technique and the diligence with
which it is performed will determine the
effect on product quality. Bottling tech-
niques not only can cause mechanical dam-
age but also may lead to great variability in
numbers of natural enemies per bottle. The
composition of the carrier material (type of
material, granule size and moisture content)
and the availability of food or carbohy-
drates (honey) and water can greatly influ-
ence the survival of the natural enemies
during storage and transportation. The
design of release cards for parasitized
pupae (E. formosa, E. eremicus) and the type
of glue and the dosing technique that are
used to apply the pupae to the cards all
influence the quality of the final product.
Depending on the product and duration of
transport, products are typically over-
packed between 5 and 15% in order to com-
pensate for mortality during the logistic
chain to the end-user.220 K.J.F. Bolckmans