Can you use Volck oil spray for black sooty mildew on crapemyrtle?
Yes, you can use Volck oil spray on Crape Myrtles. Use the growing season rate when the plants are in leaf. The crapemyrtle aphid is the pest that is probably causing the sooty mold. To gain control, you must spray the undersides of the leaves to contact the pest that is causing the damage. If the temperature is expected to exceed 85 degrees spray in early morning or late afternoon. You can spray it 4 times a season with two weeks in between treatments.