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(Ruberson et al., 1998). The predator
Aphidoletes aphidimyzacan survive periods of
3–8 months when stored at 10°C (Tiitanen,
1988). Long-term storage of the diapausing
stage of the parasitoid Trichogramma, has
been successful for periods of up to a year
and is now commercially exploited (J.
Frandon, Biotop, Antibes, France, 1996, per-
sonal communication).
Long-term storage capability is very
desirable for production companies, because:

• continuous production of the same quan-
  tity of beneficial insects is often economi-
  cally more attractive than seasonal
  production of very large numbers;


• storage facilities enable them to build up
  reserve supplies of entomophages to com-
  pensate for periods of low production or
  periods of unexpected high demand;


• storage makes rearing possible at the best
  period of the year, e.g. at a period when
  host plants can be grown under optimal
  conditions.

Collection and Shipment of Natural

Enemies

After production, the beneficials should be
delivered to the growers as soon as possible.
If delivery is looked after by the producer

and occurs within 48 h of harvesting the

organisms, no special shipment procedures

are normally needed for parasitoids and

non-cannibalistic predators other than pro-

tection against excessive heat, cold or rough

handling. When transport takes several

days, climatized containers should be used

and it may be necessary to add food (e.g.

honey in the case of parasitoids and

pollen/prey for predators). A way to over-

come problems with long times for transport

of predators is for young stages to be pack-

aged with food so that further development

takes place during transport. Packaging of

predators demands special attention when

cannibalism is a common phenomenon.

Many of the commercially available preda-

tors are generalists and exhibit cannibalism

when kept at high densities, even if food is

available in the containers for shipment. To

reduce the risk of cannibalism, it is common

to provide hiding-places for the natural

enemy by using paper, buckwheat, vermi-

culite or wheat bran in the container (see

Table 12.2). In the early days of mass pro-

duction, the biological control agents were

often collected and shipped on the host

plant on which they were reared. With the

internationalization of biocontrol, shipment

on or in inert media became a necessity.

Ingenious collection and shipping proce-

dures have been developed.

Mass Production of Natural Enemies 185

100

80

60

40

20

0

% Parasitoids trapped

216
Days stored at 8°C
Fig. 12.3.Percentage Encarsia formosafemales capable of flying (= reaching trap in short-range flight test)
when stored for 2 and 16 days at 8°C.