The Organic Gardeners Forum

Horticultural oil is just what it says it is, an oil.  It is used to smother insect eggs and scales before they hatch or move on to other parts of the plant.  There is a dormant oil, used before bud swell/break and a summer weight oil which must be timed properly and used on plants that are not stressed and well watered.  Follow the directions on the labels because while it is safe, if used improperly, it can burn your plant. 
   Neem is derived from the Neem plant ( Azadirachta indica) and is an insecticide.  It is used to kill insects.  You will see it called Neem, Azatin, Margosan on the label.  While it is a naturally occuring product, you still must use caution with it such as gloves and eye protection.  Depending on the formulation, it does have some residual activity as well as being able to drench with it but here again,  you must read the label carefully. 
   If you have a fungal problem on your pachysandra, you should first identify the problem before treating it.  Neem has been touted as a fungicide for a few problem but is very limited in it's scope.

Denise,
Can you recommend a product for spraying on my ornamentals that get lacebugs. I get it bad on my pieris japonica and some of my azaleas even though they are in a shaded area. Is it better to use neem or a light horticultural oil? And if the oil, what would be a brand I am looking for?

Thanks Jess. I will give it a try.

Can I buy SunSpray locally? I looked at several nurseries and could not find it. Do either of you order it from some online company or get it at location in our area.   I think that my pieris is too dry. It is getting shade but it gets dry where it is located. Although I have been adding more leave compost and that area is retaining more moisture. I will spray and if that does not work,  I will move it to a more northern and shady location.

Thanks Mrs. K. I will water more often. One of my plants is actually doing much better this year. I think the ammended soil is helping alot.

Joy,
      Do not use that recipe.  It's a waste of your money when you can use something specifically formulated for plants, not a salad. I don't think you would want to ruin your plants just to save a few cents. You are also like to attract some unwanted visitors to your tree with that mix.  The dormant oil should be fine on your trees if you applied it a few days ago although I'm a little concerned because you do have some buds breaking.  I wouldn't apply the Sunspray oil so soon after applying dormant oil.  I think you will be fine as is.
denise

Do y'all know an easy way to spray the undersides of leaves?? I wish I could turn all my plants upside down!

watch out for the neem.  a little bit goes a long way.  and don't let it get on your skin.  or in your eyes.  and make after you use it to wash your hands BEFORE going to the bathroom.

This discussion has been helpful in my understanding of the difference between hort. oil & neem.  Thank you all for you helpful input.  Although, I am still searching for a thorough explanation of the difference between hort. oil & safer soap.  Any thoughts...?

Horticultural oil is just that, an oil that coats the plant and more importantly offending pests, smothering them. Insecticidal soap is different product and work a little differently. The soaps kill susceptible insects by washing away the protective coating on the surface of the pest and by disrupting normal membrane functions inside the insect. Just like horticultural oil the soap must come in direct contact with the insect.

Well, how long till i can spray them then?

Did someone suggest a horticultural oil that could be used year round?  Was it the Sunspray?  It seems as though I remember that, but you know how memories go.