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Biological control: beneficial insects and mites

Cryptolaemus-System

A wolf in sheep's clothing for mealy bug control

Mealy bug is one the hardest pests to control. Its body is covered with white waxy threads, which often make a chemical pest control unsuccessful. The predatory beetle Cryptolaemus montrouzieri is a specialist in clearing mealy bug populations.

Biology: Cryptolaemus montrouzieri

Cryptolaemus montrouzieri is an Australian ladybird. Adult beetles can reach a length of 4 mm, and have black-brown wingcases. Its head, thorax an abdomen are orange-brown. The Cryptolaemus larva can reach a length of 13 mm and can be recognized by its white downy wax secretion. Due to this secretion, the larva and its prey are as like as two peas in a pod. However, the larva of Cryptolaemus is longer, more mobile and its wax threads are longer than those of mealy bugs.

The development time (from egg to larva) depends mostly on temperature. It takes about 32 days at a temperature of 24°C. A female beetle lives approximately 2 months and lays 10 eggs a day in a mealy bug colony or in a group of mealy bug eggs.

Cryptolaemus is most active when the weather is sunny. A temperature of 22-25°C and a relative humidity of 70-80% are optimal for egg laying. The beetle is not active when temperature drops to 16°C (diapause). Temperatures above 33°C confuse the beetles when looking for prey.

Glutton

Cryptolaemus is a very efficient predator for clearing mealy bug populations. Adults and young larvae eat every stage. Cryptolaemus can also have aphids or scales for a meal as an alternative to mealy bugs, if only few of them are present.

When applying Cryptolaemus in greenhouses, introduce 2-3 adults/m². It is best applied during a cool time of the day. The presence of ants in the crop adversely affects the work of Cryptolaemus. Ants are very keen on the mealy bug's honeydew and therefore protect them against this predator.

Cryptolaemus-System

Cryptolaemus montrouzieri is supplied as adults packed per 25 pieces in plastic tubes provided with a screw cap. These tubes are filled with a paper strip drenched in honey that serves as food for the beetles. After delivery they have to be introduced as soon as possible. If necessary they can be stored for a short while at a temperature of 15°C.

User's instructions

	Introduce Cryptolaemus montrouzieri as soon as the first mealy bugs are spotted.
	The quantity depends on the mealy bug infestation level. Usually 2-3 adult beetles per m² are introduced.
	Introduce the beetles in mealy bug hot spots.
	Open the tube and sprinkle the beetles on the infested plants. The introduction into the greenhouse is best done at a cool time of the day.

Note: Several pesticides have a negative affect on Cryptolaemus montrouzieri. Please be careful when controlling diseases or other pests. Consult the Biobest's list of side-effects of pesticides on beneficial organisms.