Dormant oil

Discussion in 'Pesticide & Herbicide Application' started by Prot1, Oct 27, 2003.

  1. Prot1

    Prot1 LawnSite Member
    Messages: 64

    First time poster and here it goes! My question is about applying dormant oil. I had a customer call me about treating all his trees/shrubs. I was under the impression that the leaves needed to have fallen before applying dormant oil. My customer informed me that tg/cm always applied his DO at this time of year. Am i mistaken on having the leaves off the trees or was he misinformed? He pretty much told me in other words that tg/cl would know best being a big company and all. Whos right here and what should i do? Treat now or wait until the leaves fall. Any help on this would be greatly appreciated.
  2. Grassmechanic

    Grassmechanic LawnSite Silver Member
    Messages: 2,697

    what are you treating?
  3. kickin sum grass

    kickin sum grass LawnSite Senior Member
    Messages: 628

    I am not a tree and shrub man but here in Ohio nobody ( that I know of) sprays DO until February.
  4. Ric

    Ric LawnSite Fanatic
    Messages: 11,969

    Dormant Oil is a soft leaf, hard leaf thing. % of AI, pest, time of day and irrigation factors all play a part.

    I have a small nursery and spray 1 % fine oil in middle of summer late in afternoon. Irrigation washes it off the next morning. Some soft leaf plants will defoliate if sprayed with oils.
  5. xpnd

    xpnd LawnSite Senior Member
    Messages: 378

    I always thought of dormant oil associated with fruit bearing trees or in the above case where damage to the product would make it less appealing to a potential customer.
  6. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    Dormant oil is an insecticide that works by clogging the breathing tubes of an insect. Generally it is made from paraffin and bio-degrades in the soil. Many people mix it with insecticidal soap and this combo makes a great cocktail for most ornamentals and will get most surface insects on a plant. Insecticidal soap works by causing insects to lose there skin and die it also has Fungicidal properties just like any good anti bacterial soap does. The tree hugger should love this cocktail because it has little or no impact.

    Problems are some soft leave plants also get there breathing tubes clogged and the leaves die. Oil on leaves is just like baby oil on your skin in the hot sun. Plants get Sun Burn Too.

    No I did not use scientific words in this post because I wanted to make sure everyone understood how Soap and oil works. It is very safe to use and you could take a bath in it so I think the organic forum people should like it also.
  7. GroundKprs

    GroundKprs LawnSite Bronze Member
    Messages: 1,969

    The beauty of soap and oil is that they are contact insecticides only. Any beneficial insects landing on the plant after treatment are not affected. The weakness of soap and oil is that they are contact insecticides only. Any harmful insects landing or emerging after treatment are not affected.

    The weakness is not important in a dormant oil treatment, because it is done when insects are not active. Dormant oil, properly applied, can smother all life stages of most damaging insects, however they are overwintering. For example, a good dormant oil app with get much better control of euonymous scale than any chemical insecticide at any time, in my experience.
  8. Ric

    Ric LawnSite Fanatic
    Messages: 11,969

    Aah Mr Jim

    Don't forget the lemon flavor. Sorry I don't have the time to look up some University Study. But Lemon smells help keep bugs away.
  9. Prot1

    Prot1 LawnSite Member
    Messages: 64

    Thanks for the replys guys. I was also under the impression that it could cause certain trees to defoilate. I went ahead and treated the trunks and branches as best i could. As fas as timing on the DO i also will be applying this in early spring to smother the overwintering insect eggs. Again thank you all for the responses.
  10. xpnd

    xpnd LawnSite Senior Member
    Messages: 378

    Maybe I'm from the old school but I thought that DO was used to treat relatively stationary insects such as scale primarily on fruit trees. I know that there are different weights of DO that can be used at different times of the year but I still question the generalized use of DO in the landscape as a regular treatment. Certain companies in my area sell DO as part of the basic treatment plan. DO on plants such as Bufords, Indian Hawthorne, Yaupons, Boxwoods Oaks, Ash, Redbuds, which make up 95% of the contract landscapers installation package is IMHO a waste of my time and the customer's money. There is not a noticeable or observable improvement in quality that 99% of the customers can detect. I would rather upsell a service that the customer can see a noticeable improvement post application. (However I will always sell something if the customer demands a service because s/he knows more than I do.)

    I am far from being a tree hugger however I am a big believer that a plant growing under the correct cultural and environmental conditions will have many pest problems that exceed the economic threshold treatment levels requiring the use of pesticides on a regular, be it annual, quarterly or monthly basis. I live in N. Texas. Those individuals that want durable and lasting landscapes should not be planting azaleas, junipers, eastern dogwoods or any other plant that is not adapted to our alkaline soils or host of wonderful insects that attack these stressed plants.

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