Spider mites are very small so they can’t be seen with the naked eye but they can cause a lot of damage. The first sign of their presence is pale, dirty looking patches of foliage. The simplest way to confirm their presence is too hold a piece of paper under the foliage that looks suspicious. Shake the foliage vigorously and watch for what looks like specks of dust to fall on the paper. Watch these specks closely. If they start to move, they are most likely spider mites.

To control spider mites, spray the plant with Bonide All Season Horticultural Oil. Products containing bifenthrin also gives good control. Thorough coverage is essential. Make sure to spray under the leaves. Also, avoid spraying during the heat of the day. Do not spray horticultural oils when the temperature is above 90 degrees or it may burn the foliage. Do not spray blue spruce with horticultural oils.