0851996884.pdf

E. formosais usually sold in units of 1000 as
parasitized whitefly pupae, either on the leaf
of its whitefly host plant, as pupae glued to
different substrates or as pupae that are
removed from a leaf. The recommended rate
of release ranges from 1 m^2 , every 1–2
weeks, during a certain period for preven-
tive use, to 9 m^2 , five times a week, for a
severe infestation.

Eretmocerus californicusHoward

The recommended rate of release of this par-
asitoid of Bemisiaspp. varies from 1.5 m^2
every 1–2 weeks for preventive use to 9 m^2
three times a week in a severe infestation of
whiteflies.

Eretmocerus mundus Mercet

This parasitoid is also used for control of
Bemisia spp., particularly in the Mediterranean
area of Europe. Advice for releases is the same
as for E. californicus.

Fly parasitoids

Fly parasitoids include various species of par-
asitic wasps that develop on pupae of
manure-breeding flies, such as Muscidifurax
spp., Spalangia spp. and Nasoniaspp. They are
used to reduce nuisance-fly problems by
owners of horses and to control flies in feed-
lots and other animal rearing facilities, as well
as around composting areas. Release rates
and moments vary a lot; one commonly sug-
gested release rate was 500 parasitoids per
large animal at biweekly or monthly intervals,
another release rate was related to the area to
be protected, such as 1000 parasitoids 100 ft^2.
The most common unit package marketed
included 8000–10,000 fly parasitoids (all infor-
mation from Cranshaw et al., 1996).

Leptomastix abnormisGirault

This is a parasitic wasp of mealybugs; see
under Leptomastix dactylopii.

Leptomastix dactylopii(Howard)

This species parasitizes the citrus mealybug

Planococcus citri(Risso). It is recommended

to introduce one wasp m^2 in a light infesta-

tion and two wasps m^2 in a severe infesta-

tion of P. citri. Wasps should be introduced

every 2 weeks.

Leptomastix epona(Walker)

This species is also a parasitoid of P. citri;see

under L. dactylopiiabove.

Metaphycus helvolus(Compere)

This is the most common parasitoid sold for

control of soft scales (e.g. hemispherical scale,

black scale, nigra scale and soft brown scale).

Recommended use rates: two to three releases

at 2–3-week intervals of five to ten parasitoids

per infested plant (Cranshaw et al., 1996).

Trichogrammaspp.

These species parasitize different lepidopteran

pests. Trichogrammaspp. are egg parasitoids

and are supplied as black pupae attached to

cardboard cards, as loose pupae in containers,

in capsules or in other formulations. A multi-

tude of species are produced and sold. The rec-

ommended rate of release in greenhouses

ranges from 5 m^2 for preventive use to 20 m^2

in a severe infestation. In greenhouses, pupae

should be introduced weekly. In maize with

one generation of Ostrinia nubilalis(Hubner) in

northern Europe, one release of 100,000 pupae

of different ages per hectare is advised; pupae

will emerge during a 2-week period. In North

America, the numbers released in field crops

are similar to or higher than those advised in

Europe (Cranshaw et al., 1996).

Predatory Insects

Aphidoletes aphidimyza (Rondani)

This gall midge is used for controlling

aphids. The adult gall midges are active at

Commercial Availability of Biocontrol Agents 173