Scale
Scale might be one of the most disturbing pests among aroid hobbyists. Unlike thrips or mealy bug, this particular pest is so hardy to the point cannot be manually sprayed with water. Has a rounded shape usually in brown or light brown. It attached to the leaves and may need tools to clean it up. At the same time, it’ll leave a spot on the leaves. On a severe infestation, the plant growth will slow down in general yet the leaves became smaller.
Size:
Oval shape; approximately between 1-4 mm
Syptoms:
Dwarf the plant, new growth became slower, and eventually, the plants dry out & die. You will find a colony on the leaves that usually comes with ants. On coffee (Coffea) or guava (Psidium guajava) trees, the invasion is on the buds & under the leaves. For aroids, it attacks the older leaves.
Cause:
Its manifest by air, birds, and human as its so small and attached to many surfaces.
also, caused by drought due to dry season & lack of nutrients. Some species may produce honeydew that attracts ants.
life cycle:
The eggs laid below the parent and stays there for couple of days before spread. from eggs to mature took 45-65 days depending on elevation.
Cure:
Mechanical:
cut the infected leaves
Chemical:
Diazinon, Curacron, Malathion
May need several treatments, an interval of 5-7days for 2-3 times application is recommended.