Oils have been utilized by farmers and gardeners alike lengthy earlier than chemical pesticides came to be. The unique oil used was called dormant oil because it was unsafe to use on a rising plant, however would not trigger harm when it was dormant. Due to this tradition, oils designed to be utilized to a dormant plant are actually referred to as “dormant” oils, although they’re much safer for dormant and active plants alike.
When to Spray
Dormant oils are simplest when applied to a dormant tree, shortly before bud break. The temperature needs to be above freezing for at least 24 hours, though the optimum time is when temperatures stay between 40 and 70 degrees Fahrenheit. Making use of oils throughout freezing weather will result in uneven coverage. By no means apply dormant oil to evergreen bushes.
Advantages of Dormant Oil
Because dormant oil is a mechanical means of insect control, it is unlikely that insects will develop a resistance to the oil. It’s applied directly to specific trees when the goal insects are dormant, thus decreasing the impression on helpful insects. Dormant insects are affected across the board and even eggs could be destroyed using dormant oils. Since they are highly refined, dormant oils have little affect on animals or humans.
Dormant Oil Chemicals
Dormant oils are no longer fabricated from unrefined petroleum products, but they do still comprise oils from varying sources. Most comprise naphthene and paraffin in various portions. Generally, the paraffin is in larger parts and the naphthene in smaller parts as a result of it’s more seemingly to damage plants. Some dormant oils also comprise sulfur, which can be indicated on the label as unsulfonated residue. A higher ranking indicates a decrease amount of sulfur.
Many Horticultural Oils
Dormant oil is just one form of trendy horticultural oil. The time period “dormant” is used to consult with oils which can be applied throughout the dormant season, fairly than a specific kind of oil. Superior oil is an outline that applies to all fashionable horticultural oils — these are extra refined oils that may be utilized to foliage in addition to woody plant components and are thus secure to use on growing plants. Neem oil is an oil derived from the seeds of the neem tree (Azadirachta indica), it has both fungicidal and insecticidal properties. Vegetable oils are considerably effective for insect control, but the results are mixed.
University of Illinois Extension; Simply What’s Dormant Oil?; Sandra Mason; March 2005
Oklahoma State University Extension Service; Dormant Oil; 2006
Colorado State College; Pest and Disease Control Using Horticultural Oils; Whitney Cranshaw; 2010
