Mites are a serious problem in many gardens at this time of the year. They are tiny creatures, hard to see without a magnifying glass. They suck the juice from the foliage of a wide variety of plants, including tomatoes, beans, eggplants, peppers, roses, ivy, spruce, arborvitae, marigolds and petunias.
During hot, dry weather their population expansion is sensational. There may be 10 to 15 or more generations a year, generations overlap, and all stages can be found on plants during the summer months.
Light infestations usually go unnoticed. Heavy infestations cause the leaves to turn pale or yellowish. In many cases, the leaves drop off. Badly infested plants usually have a fine cobwebby appearance of the leaves, particularly on the underside where the mites are most abundant.
They construct an extensive system of webbing, over which to travel. It not only facilitates travel but provides a convenient means of helping them keep off surfaces that have been treated with pesticides.
Use of Sevin to control insects in the vegetable garden favors mites as much as the hot, dry weather. It kills predators of mites, allowing them to increase at an even faster rate.
If your spruce, hemlock, arborvitae, red cedar or holly show a chlorotic condition, check for mites. Hold a white piece of paper below a branch and tap the branch sharply two or three times from above. Check several branches because some will have more mites than others. If mites are present they will drop onto the paper where they can be seen crawling about on the white background of the paper. They can be seen best at this time with a magnifying glass.
A method of population control that has worked for a lot of gardeners is the use of a high pressure water nozzle on the end of a water hose. Simply spray the foliage every few days or once a week with the water under pressure. Apparently the pressure of water knocks the mites off the foliage. On large evergreens, spray with water as high as you can reach from the ground level.
Check the underside of leaves of tomatoes, beans and other plants with a magnifying glass. Virginia Tech specialists recommend spraying with Kelthane for control of mites in the vegetable garden. Directions on the label for mix and application should be followed closely.
There are several kinds of mites and Kelthane appears to be effective for most kinds, according to specialists. In all cases, read and follow directions on the label.