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night. The female gall midge deposits small
orange eggs near the aphids. The emerging
larvae paralyse the aphids and suck them
dry (Koppert, 1994). A. aphidimyzais sold as
black pupae in a vermiculite carrier. The rec-
ommended rate of release varies from 2 m^2
to 10 m^2 , depending on the seriousness of
an infestation.

Chrysoperla spp.

Two species of green lacewings, Chrysoperla
carneaStehphens and Chrysoperla rufilibris
(Burmeister), are produced and used as
predators of aphids. The recommended rate
of release for C. carnea, the most common
one, ranges from 10 m^2 in a light infestation
to 20 m^2 in a severe infestation.

Cryptolaemus montrouzieriMulsant

This is a predator of mealybugs. Both the
adult beetle and its larvae can kill all growth
stages of the mealybug (Koppert, 1994). The
beetle is particularly useful for controlling
large mealybug populations. The recom-
mended rate of release in Europe varies from
2 m^2 when introduced twice with an inter-
val of 2 weeks, to 10 m^2 when introduced
once in mealybug hot spots. In North
America, the release rates are highly vari-
able; an example is a release rate of two to
five beetles per infested plant (Cranshaw et
al., 1996).

Delphastus pusillus(LeConte)

This predatory beetle is used for controlling
T. vaporariorumand Bemisiaspp. It is usually
sold in units of 100 adults. As it is a rather
new natural enemy, release rates are still
highly variable.

Ladybirds

Two species of ladybird are commercially
used as biological control agents against
aphids. Adult beetles of the species

Hippodamia convergensGuerin-Meneville are

collected in enormous quantities in the USA.

This species is not produced in Europe. It is

introduced once during the production sea-

son. The recommended release rate ranges

from 25 m^2 to 50 m^2. Harmonia axyridis

(Pallas) is a ladybird originating from Asia

and advised for use against various aphids.

Macrolophus caliginosusWagner

M. caliginosusis a predatory bug used for con-

trolling the tobacco/silverleaf whitefly B.

tabaci/argentifoliiand the greenhouse whitefly

T. vaporariorum. This predatory bug pierces

the prey with its sucking mouthparts and

sucks out the body fluids. It preys on all

whitefly stages, but prefers eggs and larvae.

An adult bug may feed on 30–40 whitefly

eggs a day (Koppert, 1994). M. caliginosusis

sold as adults in a vermiculite carrier. It is rec-

ommended for release of 0.5 m^2 to 5 preda-

tors m^2 twice, at an interval of 2 weeks.

Oriusspp.

These predatory species are used to control

thrips, such as the onion thrips, Thrips tabaci

Lindeman, and the western flower thrips,

Frankliniella occidentalis (Pergande). Orius

spp. attack larvae and adult thrips. An adult

predatory bug can eat five to 20 thrips a day

(Koppert, 1994). The recommended rate of

release ranges from 1 m^2 to 10 m^2 ,

depending on the level of pest infestation.

Currently, there are about five Orius species

on the commercial market. The most popular

species in Europe is Orius laevigatusFieber;

in North America, Orius insidiosus(Say) is

sold most often.

Predatory Mites

Amblyseius (Neoseiulus)cucumeris

(Oudemans)

A. cucumerisis marketed as a predator of

western flower thrips (F. occidentalis). This

species of thrips is currently the most prob-

174 J.C. van Lenteren