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Lime Sulfur

Folks, this item on the proper use of lime sulfur as a fungicide appeared on
the Organic Gardeling Listserver.  I know it's not SqFt per se, but as many
of us are trying to use naturally occurring materials as pesticides in our
square-foot situations, I thought you might find it useful.

The authors is Moira Ryan (theryans@xtra.co.nz).

--Janet (off); Moira (on)

>Dilip Barman wrote [to the OGList]:
>>
>> What role does lime sulfur play and is it an organic product?  Does
>> it provide any overwintering insect protection that dormant oil
>> wouldn't?  Can I use both?  Thanks!

>I don't think anybody else has got round to answering this for you, so
>even if very late, my reply may be of some use.
>
>Sulphur on its own is a fungicide favoured by organic gardeners as it is
>safe for people (You could actually eat it without causing any damage,
>though it doesn't taste at all nice!!) and safe for the environment, as
>it is an essential plant nutrient. The only things which do not like it
>are some fungi and if dusted or sprayed on to leaves it can stop or
>discourage many infections.
>
>Lime sulphur, as you might expect from the name, is prepared from
>sulphur and the same lime you might use in the garden. It is not however
>a simple mixture but comes as a clear dark reddish liquid which is even
>more effective than the straight sulphur in some cases, partly from
>being very alkaline. However, this property also causes it to be a
>severe irritant to bare skin and even more so to eyes, so it needs to be
>used carefully while wearing overalls, gloves and protective glasses..
>The alkalinity can also make it rather damaging to green foliage and it
>is most commonly used to kill fungus spores on bare deciduous wood
>during winter and up to the time when new buds just begin to unfurl.
>Instructions on the container should give you the proper safe dilutions
>to use at different stages in plant growth.
>
>One VITALLY IMPORTANT POINT is that in combination with any sort of oil
>it becomes extremely damaging to any live plant material, so it must
>NEVER be mixed with spraying oil. If you also want to use an oil spray
>on the same tree you need to allow AT LEAST TWO WEEKS between
>applications of the two products. (In fact the alkalinity means it is
>best never mixed with any other sort of spray whatsoever.)
>
> One of its classic uses is to control apple scab, and it can also help
>control several rose diseases when used as a winter spray. In some
>warmer areas where roses are grown, they may fail to go dormant in the
>winter and as this tends to be debilitating to the plants some people
>use a winter-strength solution of lime sulphur to actually burn the
>leaves and persuade them to drop (I may say I tried this myself on one
>occasion and it actually had very little effect!!).
>
>One other job which lime-sulphur does most successfully is to kill
>lichens. If you have a tree, such as an apple, which is growing poorly,
>it will sometimes get covered with a growth of lichens all over the
>fruiting wood, which can actually smother the buds.  Where this occurs a
>winter application of lime-sulphur will clean this up. HOWEVER such an
>infestation with lichen always indicates a poor hungry tree, especially
>one which is short of nitrogen and unless the condition of the tree is
>improved, a fresh crop of lichens will soon colonise it.
>
>I would say that in most situations one can get on pretty well using
>just straight spraying or dusting sulphur and probably avoid lime
>suphur, and the problems associated with applying it, altogether.

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