Mealybugs

Mealybugs look like tiny white woodlice Their pinkish-white body is covered with a type of waterproofing making chemical control difficult. They suck fluids from the plant and they deposit fluffy cotton-wool like egg masses in cracks and crevices on and around the plants. Mealybugs can multiply very quickly in warm weather and make the plant very sickly and unsightly. They occur in conservatories and greenhouses, seldom overwintering outside in the UK.

Mealybugs attack the plant by feeding on the sap and weakening it. Mealybugs also drop sticky secretions onto the leaves below, which may develop sooty mould in damp weather. It should be wiped off to allow more light to the leaf.

Mealybug young will overwinter in any indoor situation and they love the conditions found in a conservatory or greenhouse where it is both warm and light. This is a picture of the first signs of mealybug found on an olive twig in our greenhouses.

Biological Control

The brown australian ladybird eats all stages of Mealybug. In the UK it is used only in the warmth of conservatories or glasshouses, as it is not normally warm enough outside, and also the ladybirds tend to fly away. It needs high warmth and light levels to work efficiently, so it is best introduced in June to give a good 3 months of the summer before the cooler weather sets in. Cryptolaemus settle best when there are quite a large number of Mealybugs to attract them.

Unfortunately Cryptolaemus can be killed or damaged by insecticides, so its best to stop using these well before they are introduced. Soft soap can be used to wash off the plants if you are waiting for warm weather.

Click here for more about Cryptolaemus

Standard pack of 10 gives good coverage for an average conservatory where the problem is not severe. The large pack is needed where the infestation is advanced or the area larger.