How to Manage Pests

Pesticide Information

Horticultural oil

Other names: Insecticidal oil, narrow-range oil, summer oil, mineral oil, supreme oil, superior oil, dormant oil, ultrafine oil

Type

Insecticide/Fungicide/Miticide -- oil.

Plant uses

Ornamentals, fruit and nut trees, and vegetables to a lesser extent. Some plants may be sensitive; check labels.

Pests controlled

Soft-bodied insects such as aphids, immature whiteflies, immature scales, psyllids, immature true bugs, thrips, and some insect eggs as well as mites. Oils also control powdery mildew and other fungi. On corn, mineral oil can be applied to silks from a medicine dropper to control earworms.

Hazards to people

Very low toxicity; harmful if swallowed, inhaled, on skin, or in eyes.

Hazards to wildlife

Low.

Hazards to beneficials

Low; will kill soft-bodied predators or parasites exposed at the time of application; it has no residual toxicity.

Potential period of activity after treatment

Kills pests on contact, no activity after spray dries.

Precautions

For use as a dormant treatment before buds open or as a foliar spray during the spring or summer. Do not apply when plants are drought stressed, when it is windy, or when temperatures are over 90° F or below freezing. Do not spray when the relative humidity is expected to be above 90% for 48 hours, and avoid spraying oil when it is very foggy, as plant injury may occur under any of these conditions. Do not apply to oil-sensitive plants, which may be listed on the label. Do not apply within 1 month of applying sulfur. Irrigate before application to reduce water stress.

Active ingredient

Paraffinic oil or petroleum oil.

Application tips

Oils kill primarily by smothering insects and mites and an oil spray will kill only insects it comes in direct contact with at the time of application. Thoroughly spray so that all insects are covered. Be aware that many insects prefer the undersides of leaves or may be under sepals or leaf buds where they are hard to reach. Dormant treatments are ideal because, with leaves removed from trees, coverage is much more effective. A pressurized sprayer is required for application. Repeat applications will be required for pests migrating in or appearing after application.

Always check the label before purchasing or applying a pesticide product for a specific pest on a specific plant to be sure it can be applied. Follow label directions precisely.

WARNING ON THE USE OF CHEMICALS

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See How to manage pests, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/GARDEN/CONTROLS/hortoil.html revised: January 17, 2008. Contact webmaster.