Lime sulfur
Lime sulfur, lime sulfur also, is a fungicide, pesticide and acaricide. It is used since the 19th century in agriculture and is occasionally used in veterinary medicine. Its effect is due to the toxic properties of the sulfur and the strong alkalinity of the polysulphides.
The agent is generally not permitted in the European Union for plant protection, various organizations are trying to change that. In recent years it has been brought regularly for several months in the summer as approval for emergency situa tions in the trade and had limited use at this time. In Austria this is also true for February to August 2013.
Composition and properties
The usual composition in agricultural trade includes 29% ( weight volume) calcium polysulfide and a small amount of calcium thiosulfate. It is normally produced by calcium hydroxide ( slaked lime ) and elemental sulfur are boiled with water. Lime sulfur has a pH value of 10 and consists of small amounts of hydrogen sulphide.
History
Lime sulfur was first described in 1802 in England, standardized to 1850 and 1900 was worldwide in fruit growing in use. To the 1920 American citrus farmers began the effectiveness of lime sulfur against the Zitrusgallmilbe ( Phyllocoptruta oleivora ) and the mite Calacarus citrifolii to discover. Long-term success, the treatment was not. The use of lime sulfur could cause white deposits on the leaves, so that even in Zitrusbau from the 1950s, other means were used. In particular, at the beginning of the 20th century lime sulfur has been intensively studied for its fungicidal effects out there and considered about as effective as copper preparations. Lime sulfur was in agriculture to about in the 1950s, a common fungicide, until it was superseded by more modern means. End of the 20th century lime sulfur had a renaissance in organic farming.
Lime sulfur in orchards
In fruit cultivation, lime sulfur is effective against apple scab, powdery mildew and predatory mites and has this effect even at low temperatures and in relatively low doses. The performance of preventive administration is, however, lower than that of copper containing fungicides. Best effects achieved lime sulfur, when added during the first days after the infection on the wet sheet. At higher humidity, the time window is longer, may be applied in the lime sulfur without loss of efficacy.
Common indications for which Schwefekalk may be used are beyond the shot hole disease ( Stigmina carpophila ), fire blight, bacterial leaf blight and the Pfirsichkräuselkrankheit ( Taphrina deformans ).
In addition, lime sulfur has a fruchtausdünnende effect. For this, however, higher doses are necessary, as they are used in the scab. Also, a slight increase russeting treated apples by treatment with lime sulfur. Does lime sulfur directly to the fruit, this can lead to spray stains, so it is usually used only in spring and early summer. On machines that are taken by Schwelfelkalknebel, a yellowish coating forms if they are not cleaned immediately.
Its importance has lime sulfur in Europe today, especially in organic farming. In contrast to conventional agriculture apple scab is usually not controlled preventively in organic farming, lime sulfur is one of the few effective remedies that can be applied after infection. The use against scale insects is in the European Union no longer possible, since this is no registration and is not sought.
In warmer climates lime sulfur is still the standard means of combating the mite Aceria sheldoni and Fransenflüglers Scirtothrips aurantii on citrus.
Lime sulfur in veterinary medicine
A 2% Schwefelkalklösung can be used in the dermatophytoses cat. It is this shaved and wet the skin with Schwefelkalklösung, and dried the cat afterwards.