Microscopic erineum mite makes its mark.

We all know some leaves turn red in the fall, but what causes velvety-red crusty patches on a leaf in spring? The answer has to do with a tiny erineum mite.

Mites are terribly small arachnids, a relative of spiders, and may be so small that they are invisible to the eye. Dust mites are about a quarter of a millimeter long (0.25 mm). Crimson erineum mites are even smaller, being approximately 0.15 mm (0.006 inches) in length. These mites have lost the back legs and only use the front four; you can see a scanning electron micrograph of one by clicking here. It would take 170 of these animalcules mounted end to end to produce a one-inch line.

While wandering about with my macro setup I came across some leaves infected with the erineum mite. At the time I had no idea what caused the bright red velvety patches and, as is my habit, decided to photograph a specimen and look it up later. It turns out that the mite does not usually seriously injure the host plant. They typically represent a "small" problem. If you detect its presence you can simply remove the leaves and discard them a safe distance away. The mite overwinters in buds or on fallen leaves and will invade the plant in the spring. There is a lot more information on them at this website.

Thanks for reading.     Ericspix     Eric Svendsen