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ages of emergence, but the ability to fly is
much lower for the parasitoids that were
stored for 16 days (Fig. 12.3). This test was
done with the short-range flight cylinder as
described in Chapter 19. Storage during the
adult stage leads to even higher and faster
reduction in fitness than with storage of
immatures. The pupal stage seems to be
most suitable for short-term storage.
Data on long-term storage of natural ene-
mies or their hosts are limited. Host material
(e.g. eggs of Sitotroga cerealellaand Grapholita
lineatum) stored for long periods (in the case
of Grapholitafor up to 5 years) in liquid nitro-
gen could still be used for production of
Trichogrammaand Trissolcus simoni, respec-
tively (Gennadiev and Khilistovskii, 1980).
Eggs of Ephestia kuehniellacan be sterilized
by ultraviolet (UV) radiation or freezing, and
then be stored at low temperature for several
months without losing their value as alterna-
tive food for mass production of predators
such asChrysoperlaand Orius.

The parasitoid Diglyphus isaea can be

stored at a low temperature for at least 2

months, during which time mortality does

not increase and fecundity remains the

same (Burgio and Nicoli, 1994). Hagvar and

Hofsvang (1991) reported that some species

of Aphidiidae (e.g. Aphidius matricariae) can

be stored at low temperatures for several

weeks.

The possibility of storing beneficials in

the diapausing stage has been studied, but

most of this work has not yet led to practical

application, because unacceptably high mor-

tality occurred during the artificially induced

diapause. There are, however, some positive

exceptions. Diapausing adults of the preda-

tor Chrysoperla carneacan be stored at a low

temperature for about 30 weeks while main-

taining an acceptable level of survival and

reproduction activity (Tauber et al., 1993).

Also the predator Orius insidiosusmaintains

good longevity and reproduction rate after

storage in diapause for up to 8 weeks

184 J.C. van Lenteren and M.G. Tommasini

Sow tobacco seeds in pots

in greenhouse

ReleaseEncarsia formosa

to parasitize whiteflies

Harvest part of the leaves

with black pupae

1st generation of E.

formosa, remove black

pupae from leaves, ship

to grower

Unparasitized whiteflies

emerge, fly to upper leaves of

tobacco plants and oviposit

Harvest part of the

leaves with black pupae

2nd generation ofE.

formosa, remove from

leaves and ship

Harvest part of the leaves

with black pupae

3rd generation of E.

formosa, remove from

leaves and ship

All developments take place on same tobacco plants in same

greenhouse for several months

4–8 weeks

2–3 weeks

2–3 weeks

2–3 weeks

2–3 weeks

2–3 weeks

1–2 weeks

1–2 weeks 1–2 weeks

etc.

2–3 weeks

etc.

Release whitefly adults to

infest tobacco plants

E. formosa emerge from

black pupae, move up in plant

and parasitize whitefly

E. formosa emerge from

black pupae, move up in plant

and parasitize whitefly

Unparasitized whiteflies emerge,

fly to upper leaves of tobacco

plants and oviposit

Fig. 12.2.‘Continuous’ production scheme for the whitefly parasitoid Encarsia formosa.