石灰硫黃合劑 lime sulfur
石灰硫黃合劑 lime sulfur
比值 生石灰:硫黃:水=1:2:10-15
玻美比重 28-30 左右
In horticulture, lime sulfur (British spelling lime sulphur) is
a mixture of calcium polysulfides formed by reacting calcium hydroxide with sulfur, used in pest control. It can be prepared by boiling
calcium hydroxide and sulfur together with a small amount of surfactant. It is normally used as an aqueous
solution, which is reddish-yellow in colour and has a distinctive offensive
odour.
Contents
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2Use
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3Safety
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4History
o
5.1Notes
A New York State Agricultural
Experiment Station recipe for the concentrate is 80 lb. of sulfur, 36 lb. of
quicklime, and 50 gal. of water. About 2.2:1 is the ratio (by weight) for
compounding sulfur and quicklime; this makes the highest proportion of calcium
pentasulfide. If calcium hydroxide (builders or hydrated lime) is used, an
increase by 1/3 or more (to 115 g/L or more) might be used with the
192 g/L of sulfur. If the quicklime is 85%, 90%, or 95% pure, use
101 g/L, 96 g/L, or 91 g/L; if impure hydrated lime is used,
similarly increase its quantity. Avoid using lime that is less than 90% pure.
Boil for an hour, stirring and adding small amounts of hot water to compensate
for evaporation.
Lime sulfur is sold as a spray
for deciduous trees to control fungi, bacteria and insects living or dormant on the surface
of the bark. Lime sulfur
burns leaves so it is not as useful for evergreen plants.
Bonsai enthusiasts use undiluted lime
sulfur to bleach, sterilise, and preserve deadwood on bonsai trees while giving
an aged look.[1] Rather than spraying the entire
tree, as with the pesticidal usage, lime sulfur is painted directly onto the
exposed deadwood, and is often colored with a small amount of dark paint to
make it look more natural. Without paint pigments, the lime-sulfur solution
bleaches wood to a bone-white color that takes time to weather and become
natural-looking.[2] Because the lime sulfur does not
contact the leaves or needles, this technique can be used on evergreen trees as
well as other types of trees.
Diluted solutions of lime sulfur
(between 1:16 and 1:32) are also used as a dip for pets to help control ringworm (fungus), mange and
other dermatoses and parasites. Undiluted lime sulfur is corrosive
to skin and eyes and can cause serious injury like blindness.
Lime sulfur reacts with strong acids (including stomach acid) to produce highly toxic hydrogen sulfide (rotten egg gas) and
indeed usually has a distinct "rotten egg" odor to it. Lime sulfur is
not extremely flammable but combustion produces highly irritating sulfur dioxide gas.
Safety goggles and gloves should
be worn while handling lime sulfur. Lime sulfur solutions are strongly alkaline(typical commercial concentrates have
a pH over 11.5), and so it is corrosive to
living things and can cause blindness if splashed in the eyes.
Lime sulfur is believed to be the
earliest synthetic chemical used as a pesticide, being used in the 1840s
in France to control grape vine powdery mildew Uncinula necator,
which had been introduced from the USA in
1845 and reduced wine production by 80%. In 1886 it was
first used in California to
control San Jose scale.
Commencing around 1904, commercial suppliers began to manufacturer lime sulfur;
prior to that time, gardeners were expected to manufacture their own. By the
1920s essentially all commercial orchards in western countries were
protected by regular spraying with lime sulfur. However by the 1940s, lime
sulfur began to be replaced by synthetic organic fungicides which risked less damage to
the crop's foliage.
2. Jump up^ Chan, Peter (1987). Bonsai
Masterclass. Sterling Publishing Company Inc. pp. 146–147. ISBN 0-8069-6763-3.
"Chemical Investigation of Best
Conditions for Making the Lime-Sulfur Wash." L.L. Van Slyke, A.W.
Bosworth, & C.C. Hedges, New York Agricultural Experiment Station Bulletin
No. 329, December 1910, Geneva, New York
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