How to recognize armoured scales

Armoured scales are small insects that are protected by a hard scale cover. The cover completely protects the body and is the only visible body part of the insect. The cover protects the insect from dehydration and even pesticides. Unlike in soft scales, the cover of armoured scales can be removed from the body. 

Armoured scales can have many different shapes. Some species are perfectly round during all stages, while others are round only in young stages and become more elongated in older stages. There are even species that always have an elongated body shape. In several species the body shape differs between males, who are often elongated, and females, who are mostly round. In some species males develop in a white, waxy elongated cocoon which is easily confused with mealybugs.  

Armoured scales damage

Although armoured scales are less common than mealybugs and soft scales, they can be a rather persistent pest. Armoured scales suck plant saps and can transmit viruses Their presence is usually noticed by yellow spots on the leaves, which are caused by secretion of substances during feeding. During heavy infestation plants can be sucked dry, starting with shoots and continuing on to stems. Armoured scales do not produce honeydew, in contrast to soft scales and mealybugs.  

Armoured scales have a broad host range in- and outside greenhouses. Greenhouse crops that are affected are mainly ornamentals like, orchid, rose, palm, cactus, and ferns. Some armoured scales species are specific for a certain crop, while others are more generalistic and can be found on several crops.