Citrus mealybugs are a little sap-sucking insect, grey with a dusty white waxy covering. They tend to affect glasshouse plants or houseplants as they require warm temperatures to survive. They tend to live together in dense groups, in protected parts of plants. As they suck large amounts of sap from plants, to gain sufficient nutrition, they produce a sticky, sugary substance, called honeydew. This honeydew falls on to the leaves below infestation, and a grey mould called sooty mould may develop. This mould may reduce the plants' ability to photosynthesise. Activity is reliant on temperature but can be found on plants indoors or glasshouses most of the year. Summertime infestations are most common. There are many generations in a year if conditions are continuously warm.