One tree service tells me they will apply at 2" intervals, one at 6" intervals -- big cost difference! Who is using it right?
When it comes to chemical applications always follow what the label states. Below is a section of the Mauget Dinocide Product Label.
So you measure the DBH and divide that number by 2. This gives you how many capsules you need. Then you look at the DBH to determine what mL capsules to use. So if the tree was a 20" DBH you would be using 3mL capsules and using 10 of them equally spaced around the base of the tree.
3. NUMBER OF CAPSULES
Measure the tree at breast height in inches. If measuring the circumference, divide this number by six (6) to determine the number of capsules needed. If measuring the diameter at breast height (DBH), divide this number by 2 (two) to determine the number of capsules needed. If the number of capsules results in a fraction, round down to the lower whole number.
The following dosage, per capsule, depends on tree diameter:
2mL capsules – 2 to 10 inches DBH
3mL capsules – 11 to 36 inches DBH
4mL capsules – 37 inches DBH and above.
6mL capsules – narrow-leaved evergreen trees.
For heavier infestation and/or more persistent insects, use 4 mL capsules on all tree sizes. For narrow-leaved evergreen trees such as pine, spruce, or hemlock, use the 6 mL capsules at 4-inch circumference spacing (DBH divided by 1.3). Trees in advanced stages of insect infestation may not respond to treatment. The health, species of the tree and the environmental conditions will determine the rate of uptake.