Lime-sulfur sprays

Miscellaneous. Both whiting and hydrated lime are used as diluents and carriers of pesticides, such as lime—sulfur sprays, Bordeaux, calcium arsenate, etc. The most widely used bleach and sterilizer, high test calcium hypochlorite, is made by interacting lime and chlorine (see Bleaching AGENTS). Calcium and magnesium salts, such as dicalcium phosphate, magnesium chloride, lithium salts, etc, are made directly from calcific and dolomitic lime and limestone. 

The development of resistant strains of an insect to a given insecticide is not new. Melander (7) in 1914 pointed out that the San Jose scale in Washington had developed a resistance to lime-sulfur sprays. Recently Babers (1) of the Bureau of Entomology and Plant Quarantine brought together an excellent evaluation and summary of the literature dealing with the development of insect resistance to insecticides he lists 111 references to work on this phenomenon. 

In 1875 Pollacci (7) reported grape leaves treated with sulfur produced hydrogen sulfide gas. Recently it has been reported that hydrogen sulfide gas is produced by sulfur-dusted lemons and oranges (22). This gas which emanates from sulfured plants is also produced by the reactions of ingredients in the widely used lime-sulfur sprays. St. John and Groves (9) have excellently reviewed the chemistry of these mixtures. 

Uses of sulfur. In the elemental form, sulfur is used (1) in the vulcanization of rubber (2) in the manufacture of black powder (3) as a fungicide (in powder form), particularly in growing grapes and (4) as lime-sulfur spray for fruit trees. Although the preceding uses require considerable amounts of this element, the great bulk of the world s production of sulfur goes into the manufacture of sulfur dioxide, which may be used as such or converted to other industrially important sulfur compounds, some of which are discussed later. 

Because it is cheap, calcium hydroxide is used in many chemical processes that require a strong base. It is used in the production of sodium hydroxide, ammonia, bleaching powder, and many other chemicals. Calcium hydroxide is also used as an insecticide in the form of lime-sulfur spray, in water softening, and in the production of numerous materials such as stucco and mortar which are widely used in the building construction industries. 

While there are some real problems to be solved which involve residues, insect resistance to insecticides is the really big problem. Curiously, the opponents of pesticides fail to measure it in its full dimensions. Resistance of insects to insecticides is a truly growing problem. As long ago as 1908 the repeated use of lime-sulfur sprays in orchards in Clarkson Valley, Washington, selected out a resistant strain of the San Jose scale, which spread and reached southern Illinois orchards in 1920. Then there followed three species of scale insects... 

Leaves covered with a white powdery coating. Cause Powdery mildew. Leaves may also be twisted or stunted and a powdery coating may cover fruit. Rainy weather does not cause this fungal disease to spread. It is most common in weather patterns featuring cool nights changing to warm days. For control, apply sulfur or lime-sulfur spray. Northstar sour cherry is resistant to powdery mildew. 

Leaves puckered and reddish. Cause Peach leaf curl. Later in the season, infected leaves may yellow, shrivel, and drop. New growth is stunted and swollen and often dies. Fruit often drops prematurely and may have a reddish, irregular, rough surface. See page 165 for an illustration of this disease. You can t cure this fungal disease during the current season, but copper sprays or lime-sulfur sprays help control it. Resistant cultivars include Candor , Clayton , Com-Pact Red Haven , Correll , Dixieland , Elberta , Red Haven , and Stark EarliGlo . 

Fruit covered with a powdery w hite coating. Cause Powdery mildew. This fungal disease, most common on red raspberries, makes fruit inedible and may weaken or kill whole canes. Pruning out old canes to provide good air circulation aids control. To prevent the disease, apply sulfur dusts. To control e.xisting infection, apply lime-sulfur spray. Resistant cultivars... 

To control all 3 of these diseases, also use cultivation methods that help prevent fungal infections. Maintain good air circulation by selecting a sunny, well-drained site. Each fall, remove diseased or crowded canes at ground level. Prune when plants are dry and rain is not expected for the next 3 days. For persistent fungal infection, apply lime-sulfur spray just as leaf buds break in the spring. 

European black, 86 lime-sulfur spray for, 477 Pinus and, 18.3 problems of, 86 red, 86 white, 86... 

Bordeaux mixtures lime-sulfur spray calcium arsenate dispersing agent starfish control ... 

Lime-sulfur sprays contain one part of hydrated lime to two parts of sulfur. They may be applied as a powder or as an aqueous spray [30.1]. 

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