Cryptolaemus montrouzieri adults were one of the first biological controls used by professionals for the control of citrus mealybug. These ladybirds are excellent killers of mealybugs in greenhouses, conservatories or heated areas. Native to Australia these little predators are highly regarded throughout the world for effective natural control of mealybugs on cactus, succulents and many other greenhouse plants. Use these predators when infestations are large or when mealybugs are found in colonies.
Mealybugs are white and fluffy in appearance, they produce a waxy material which infects the plants with sticky, sooty moulds. Cryptolaemus adults will help to control these outbreaks by consuming large numbers of pests!
Mealybug predator adults will search for prey in greenhouses and conservatories. They will feed on all stages of the mealybug life cycle including eggs, larvae and adults. If mealybug is not available to prey on Cryptolaemus will also feed on aphids and scale insects at a lower rate.
Cryptolaemus are generally only used in heated environments in the UK. They require a temperature of at least 16 degrees to begin feeding on mealybug. Optimum control is found between 20-25 degrees with high levels of light.
Dragonfli expert Julian Ives advises applying Cryptolaemus adults at the following rate;
Light infestation - 5 adults per square metre
Heavy infestation – 10 adults per square metre
Repeat applications may be required on heavy infestations, add more adults every 2 weeks until populations of Cryptolaemus can be observed on the plant. Around 2-3 weeks after application, given adequate levels of prey, Cryptolaemus larvae should be observed on the plants too.
Use Cryptolaemus adults if mealybugs are in colonies or in very high numbers. These will breed and their larvae should be observed 2-3 weeks after first applying adults. The larvae too will consume large numbers of pest.
If you have a lighter infestation begin with Cryptolaemus larvae applied directly to infested areas, after 12-21 days these larvae will develop into adults.
With suitable conditions and adequate levels of prey the Cryptolaemus lifecycle is usually around 25 days, they will however begin to breed. Females lay their eggs on the mealybug wool and after around 7 days these will hatch into larvae. The larvae are also voracious predators of mealybugs and will consume large numbers of pest for 12-21 days before pupating into adults.
Release Cryptolaemus adults ideally in the evening directly onto the colonies of mealybug, they will sense their prey and begin to consume the mealybugs! Ensure windows are shut before applying and cover with mesh to avoid adults escaping if needed.
Please Note; Cryptolaemus is a living creature and can be affected by any chemical pesticides used within the previous few weeks. As a guide cease using pyrethrum or SB plant invigorator 2 days prior to use and other persistent chemicals or universal bug killers 1-2 weeks before using Cryptolaemus.