Pseudoococcidae - Working similarly to aphids, mealybugs suck the juices particularly of greenhouse plants and house plants, causing the leaves to yellow and the plant to die. As well as sucking sap they produce an excess of honeydew which can cause sooty mould, particularly on lower leaves. Keep an eye out for their 'wool', which is essentially where the eggs are laid. 

Not to worry though! The larvae of our little friend Cryptolaemus feed on mealybug larvae before pupating into a ladybird, who, after munching on some more mealybugs, will lay her eggs next to those of the mealybug, producing your next generation of soldiers, which, unlike the mealy bug, can fly to each of your plants, wiping out the infestation. Available in packs of 10 and 25.

A mealybug...

...and our friend Cryptolaemus