A leaf-brushing machine and microscope are generally used to count mites. The leaf-brushing machine is a device with rollers covered with soft bristles that brush mites from the leaf onto a revolving glass plate coated with a slightly sticky substance. A microscope is used to distinguish individual species and stages. A paper grid like the one above is placed beneath the glass plate to help keep track during the count.
This grid can be printed for this purpose. You may print directly from your web browser. However, depending upon the way your web browser is configured, the size of the printed image may not be what you want. To gain more control over the printed size, you may want to copy the graphic from your browser to your computer (usually using a right mouse click). The size as published in the original Orchard Pest Management book is 5.16" in diameter. The graphic on this page is 372 pixels in diameter. One scaled at 1548 pixels is also available.