Oil products can be used as dormant oils, growing-season sprays or spray adjuvants for smothering such pests as overwintering scales, mites, aphids, and peach twig borer. The active ingredient in most horticultural oil (also called dormant oil, insecticidal oil, narrow-range oil, superior oil) is Paraffinic or Petroleum oil. Dormant oil is an insecticide and miticide used to kill soft bodied insects such as aphids, thrips, scales, and mites. Also smothers insect eggs (including coddling moth eggs). Must have contact with insects/mites or eggs, not effective after it dries.
Dormant spraying is a very important action to take in preventing damage by insect pests, fungus, and disease. Codling moth, for example, is a common pest of apples and pears, and Peach Leaf Curl is a common disease of peaches and nectarines in California. Applying Horticultural Oil and Fungicide/Bactericide three times during the dormant season will greatly reduce the chance of infestation. You can use the following guidelines and holidays as a reminder for spraying: The first spray should be just after most of the leaves have dropped (Thanksgiving), the second at full dormancy (New Year), the third at bud swell (Valentine’s Day). The holidays generally correspond with the life cycle of deciduous plants, but always use your own observation to decide when to spray. It is also wise to research the specific species of fruit or nut for particular needs and precautions in regards to dormant spraying. Peaceful Valley carries three choices for fungicide and/or bactericides: Lime Sulfur, Sulfur, and Copper. Choose one along with the horticultural oil for dormant spraying.
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