Managing mealybugs with biological controls

What are mealybugs?

Mealybugs are related to aphids and feed by sucking plant sap, they cause damage directly via feeding and also by attracting sooty mould growth on plants through the secretion of honeydew, a by-product of sap feeding which is rich in sugars attracting species such as ants which will deter predatory species. Most mealybug species will target the stems and veins of plants however, some species will attack roots with this pest also able to transmit viruses but usually via tropical plants.

Originating from tropical and subtropical regions, they are serious pests within the industry, they are able to thrive within protected structures, most particularly in areas such as atriums with slow growing plants. They are also common in botanic gardens, interior landscapes and in commercial ornamental and edible crops, especially pepper and tomato.

Mealybug populations can persist all year round given the right environmental conditions with adults able to survive for a number of months on inert surfaces such as canes, ties and pots.

Cryptolaemus ladybirds and other biologicals are available for control under warmer conditions. Lacewing larvae also feed on mealybug nymphs. Hypoaspis may feed on root mealybug as well as other types that drop onto the growing media surface. A pheromone is available for the citrus mealybug that attracts the winged adult males of several species. For further information on our biological controls, please see below.

Mealybug lifecycle

The lifecycle of a mealybug is different for both males and females from the 2nd instar growth stage onwards, first transitioning from egg to crawler to 2nd instar where, the female will start to develop the white waxy material which is a key identifying feature of this pest, and finally onto a fully developed adult female.

The males at the 2nd instar growth stage will breakaway and form a waxy pupa cocoon and finally develop into flying males, able to migrate across a glasshouse with a very short lifespan due to the fact they have no mouth parts.

Mealybug species

Listed below are three key mealybug species that present an issue for growers, please get in touch with us if you have any questions or concerns regarding potential mealybug infestations. 

• Glasshouse mealybug, Pseudococcus viburni

Originating from South America, this species has the potential to be a major pest on crops including, tomato and pepper crops under protected environments. Identified by the white waxy coating on the body with filaments around the body structure and two filaments protruding to 20-50% of the body size.

• Citrus mealybug, Planococcus citri

This species is waxy coated and can be identified by the 18 pairs of waxy filaments surrounding the body with two slightly longer tail filaments and a dark band down the centre of the body which is absent of wax. 

• Long-tailed mealybug, Pseudococcus longispinus

This species is wax coated and similar to citrus mealybug having a dark band down the centre of the body. They are best identified by the long tail filaments which are approximately the same length as the body. This species also has a slightly different lifecycle in that it gives birth to live young which remain close to the parent.

Biological controls of mealybug

Please click the links below for biological control options for mealybug control.

Cryptolaemus montrouzieri

This ladybird species originating in Australia is a voracious predator of mealybug with both adults and larvae being predatory. Temperature is an important factor with this species and requires an environment of approximately 16 ˚C however, temperatures above this are advised for development up to 30˚C, below 9˚C there is no activity. The adults can fly so distribute evenly across the affected areas and apply later in the day during reduced light hours or under a fleece to minimise losses through vents or openings.

Identification is key regarding the mealybug species when selecting this predator as Long-tailed mealybug is not as effectively controlled by this predator due to the viviparous nature of the pest (giving birth to live young) and the Australian ladybird requiring an egg mass to lay their eggs in, with 200 to 700 eggs laid in each mealybug eggs mass.

They also have a polyphagous diet, feeding on scale insect and aphids when mealybug is at low populations.

Chrysoperla carnea 

This species is a very useful generalist predator feeding mainly on aphid but will also predate mealybug, scale insect, thrips, spider mites, whitefly, and young caterpillars. Fargro offers this predator in loose product larvae and application should be made evenly across the affected area, the larvae can be cannibalistic if food is scarce so product should not be heaped in close proximity.

Find out more

For more information on our biological control options please contact bio sales on 01903 256857 or email