Sulfur lime

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Lime sulfur , also called lime sulfur broth , is a fungicide , pesticide, and acaricide . It has been used in agriculture since the 19th century and is occasionally used in veterinary medicine . Its effect is based on the toxic properties of sulfur and the strong alkalinity of polysulfides .

Lime sulfur is approved as a crop protection agent in some countries of the European Union . Various associations are trying to change this. In recent years, it has been regularly put on the market for several months in the summer as a license for emergency situations and its usability was limited during this time. In Austria, this also applied from February to August 2013.

Composition and properties

The common composition in the agricultural trade contains 29% (weight volume ) calcium polysulphide and a small amount of calcium thiosulphate . It is usually made by boiling calcium hydroxide (slaked lime) and elemental sulfur with water. Lime sulfur has a pH of 10 and releases small amounts of hydrogen sulfide .

history

Sulfur lime was first described in England in 1802, standardized until 1850 and was used in fruit growing around the world around 1900. Around the 1920s, American citrus farmers began to discover the effectiveness of lime sulfur against the citrus gall mite ( Phyllocoptruta oleivora ) and the mite species Calacarus citrifolii . The treatment was not successful in the long term. The use of sulfur lime could lead to white deposits on the leaves, so that other means were also used in citrus cultivation from the 1950s onwards. At the beginning of the 20th century in particular, lime sulfur was examined intensively for its fungicidal effects, and was estimated to be about as effective as copper preparations. Lime sulfur was a common fungicide in agriculture until around the 1950s, when it was superseded by more modern agents. At the end of the 20th century, sulfur lime had a renaissance in organic farming.

use

In fruit growing

In fruit growing, sulfur lime acts against apple scab , powdery mildew and predatory mites and has this effect even at low temperatures and in comparatively low doses. However, the performance of preventive administration is lower than that of fungicides containing copper. Lime sulfur has the best effects if it is placed on the wet leaf in the first few days after infection. With higher air humidity, the time window is longer in which sulfur lime can be applied without loss of effectiveness.

Common indications for which sulfur lime can also be used are shotgun disease ( Stigmina carpophila ), fire blight , bacterial blight and peach curl disease ( Taphrina deformans ).

In addition, lime sulfur has a fruit-thinning effect. However, higher dosages are necessary for this than are used in scab control. Treating apples with sulfuric lime can also slightly increase their russeting. Lime sulfur hits the fruit directly, this can lead to splash marks, so that it is usually only used in spring and early summer. A yellowish film will form on machines that are hit by the lime sulfur mist if they are not cleaned immediately.

In Europe today, sulfur lime is particularly important in organic farming. In contrast to conventional agriculture, apple scab is usually not combated preventively in organic farming; sulfur lime is one of the few effective agents that can also be applied after infection. The use against scale insects is no longer possible in the European Union, as there is no approval for this and is not sought.

In warmer climates, lime sulfur is still the standard remedy for combating the aceria sheldoni mite and the fringed winged Scirtothrips aurantii on citrus fruits.

When designing bonsai

Bonsai with bleached dead wood

Bonsai lovers use undiluted lime sulfur to sterilize and bleach the surfaces of dead wood areas . Treated parts of the plant take on an aged appearance after the application of sulfur lime.

Veterinary medicine

A 2% calcium sulphide solution can be used for dermatophytosis in cats. This is sheared and the skin is moistened with calcium sulfate solution, and the cat is then dried off.

medicine

Lime sulfur broth is used in medicine - usually under the name Vleminckxsche solution - to treat scabies (as an antiscabiosum ).

If you add diluted hydrochloric acid to a calcium polysulphide solution, a milky white suspension of finely divided sulfur in a dilute calcium chloride solution is created, which is used as sulfur milk against skin diseases, among other things.

Industry

Lime sulfur broth can also be used to produce absorber masses to remove heavy metals from combustion gases or to remove chromate from waste water.

Remarks

  1. ↑ a b c Beate Golba: Alternatives to the use of copper-containing preparations in apple cultivation (PDF; 432 kB)
  2. ^ Directorate-General for Health and Food Safety of the European Commission: Entry on Lime Sulfur (calcium polysulphide) in the EU pesticide database ; Retrieved June 20, 2016.
  3. ^ Christian Scheer: Building blocks of the strategy against scab , BWagrar - 9/2013, p. 40
  4. ↑ Federal Office for Consumer Protection and Food Safety: Approvals for emergency situations (last change: March 28, 2013) ( Memento of January 7, 2015 in the Internet Archive ) , March 28, 2013
  5. ↑ a b Federal Office for Food Safety: Plant Protection Products Register - extract from the register , accessed April 7, 2013
  6. ↑ a b c Imre J. Holb: Fungal Disease Management in Environmentally Friendly Apple Production A Review in: Eric Lichtfouse (ed.): Climate Change, Intercropping, Pest Control and Beneficial Microorganisms Springer, 2009, ISBN 9048127165 , p. 258
  7. ^ RH Messing and BA Croft: Pesticide Resistance in Eriophyoid Mites, their Competition and Predators. in: EE Lindquist, J. Bruin, MW Sabelis: Eriophyoid Mites: Their Biology, Natural Enemies and Control Elsevier, 1996, ISBN 0080531237 , p. 699
  8. ↑ Karl Waltlt: Quassia and sulfur lime broth - use in organic fruit growing Besseres Obst 4/2008, pp. 12-14
  9. ↑ Fruit growing, plant protection advice in South Baden: Plant protection warning service for commercial fruit growing in South Baden (PDF; 135 kB) , March 13, 2012, pp. 1–2
  10. ↑ Dennis S. Hill: Pests of crops in warm climates and their control Springer, 2008, ISBN 1402067380 , p. 508
  11. ↑ Dennis S. Hill: Pests of crops in warm climates and their control Springer, 2008, ISBN 1402067380 , p. 262
  12. ↑ Kathrin Hartmann, Jutta Hein: Infectious Diseases of the Cat Kluwer, 2008, ISBN 3877067468 , p. 332
  13. ↑ a b c Entry on calcium polysulphides. In: Römpp Online . Georg Thieme Verlag, accessed on April 5, 2019.