Dormant Spray for Persimmons

Dormant Oil

• Use oil sprays to control scale insects on persimmon trees. A true dormant oil is heavier than a horticultural or summer oil and may damage tender new growth when sprayed on a tree in spring. Look for an oil labeled as horticultural or summer oil. Regardless of the product you use, dilute the oil with water, according to the label instructions for the time of year you will use the spray. The label will tell you how to adjust the strength and time the treatments.

Scale Insects

• Scales are unusual pests that may appear to be growths on the tree rather than insects. Adult scales seldom move and look like hard, round or oval lumps with no distinguishable body parts. Once they begin feeding, they develop a hard outer coating that insecticides can’t penetrate. Immature scales are small, soft-bodied insects that move freely around the tree. Treatment targets the immature insects, called crawlers, which are vulnerable to insecticides and oil sprays. The crawler stage is brief, so careful timing is essential.

When to Spray

• Use dormant oil spray as a preventative in winter, while the tree is dormant. Use horticultural or summer oils while the insect is in the crawler stage. This stage in a scale’s life cycle usually occurs just before the buds begin to swell. If you noticed scale insects during the previous season, you will probably have them again. Begin monitoring the tree for crawlers in late winter and early spring and spray as soon as you detect them. Pieces of sticky traps or double-sided tape will help spot them.

Application

• Read the package label and carefully follow the precautions and instructions. Spray on a day when temperatures are above 40 degrees Fahrenheit and humidity is below 65 percent. The spray has to come into contact with the insect to be effective, so spray the tree thoroughly and to the point where it drips from the foliage and branches. Insect management usually requires two treatments, 10 to 14 days apart.