Taxonomy order: Hemiptera

Description: Common flightless, flat sap sucking insects. Scale insects thrive in warm, dry environments. The scale insect is oftern small, oval and flat, with a protective tan to brown shell-like covering (scale). Scale consist of up 7,000 species of tiny sap-sucking insects, however they are categorized to either Armored scale, Soft scale or Mealybug.

Distribution on the plant: Scale generally targets leaf joints and the undersides of leaves. almost always arranged in clusters.

Determent to crops: Scales, both armored and soft, are the most destructive. Armored scales are more difficult to control once mature. Soft scale bugs excrete large amounts of honeydew, which encourages the growth of sooty mold, a black-colored fungus that interferes with photosynthesis. Mealybugs are easier to control. Scales cannot fly so, dispersal depends on the movement of crawlers. Sapsucking weakening plants and transmitting plant virus. 

Scale-damaged plants look withered and sickly. Leaves turn yellow and may drop from the plant. They may also have sticky sap or a black fungus on the leaves and stems.

For more information use the Spruce website (link), or Gardening Know How (link).

Monitoring remarks: Crawlers may be detected by placing double-sticky tape on plant branches.

Action threshold: Suppress when visually seen.

Control general remarks: Biological options include Rhizo Protect, Saf-T Side and Prevail-P. Systemic synthetic products can be most effective for mature amoured scale.