Agriculture Reference
In-Depth Information
11. Inorganic Sulfur
Elemental sulfur is an acaricide and fungicide widely used on orchard, or-
namental, vegetable, grain, and other crops. It is prepared as dust in various
particle sizes and applied as such, or it is formulated with various minerals to
improve flowability, or is applied as an aqueous emulsion or wettable powder.
Commercial products that are currently available include Brimstone,
Lacco Sulfur, Clifton Sulfur, Sul-Cide, Cosan, Kumulus S, Sofril, Sulfex,
Thiolux, Thiovit, Magnetic 6, Liquid Sulfur, Thion, Zolvis, and Golden Dew.
Toxicology and Mode of Action
Elemental sulfur is moderately irritating to the skin, and airborne dust is
irritating to the eyes and the respiratory tract. In hot sunny environments,
there may be some oxidation of foliage-deposited sulfur to irritating gaseous
sulfur oxides, which are very irritating to the eyes and respiratory tract.
Ingested sulfur powder induces catharsis, and has been used medicinally
(usually with molasses) for that purpose. Some hydrogen sulfide is formed in
the large intestine and this may present a degree of toxic hazard. However, an
adult has survived ingestion of 60 grams.
Ingested colloidal sulfur is efficiently absorbed by the gut and is promptly
excreted in the urine as inorganic sulfate.
12. Insect Repellants
a. Diethyltoluamide (DEET)—This chemical is one of the most widely used
liquid insect repellent used today. It is suitable for application to skin or to
fabrics. It is formulated with ethyl or isopropyl alcohol, usually in pressur-
ized containers.
Commercial products that are currently available include Detamide, Meta-
delphene, MGK, OFF, and Repel.
Toxicology and Mode of Action
For many years, diethyltoluamide has been effective and generally well
tolerated as an insect repellent applied to human skin, although tingling, mild
irritation, and sometimes desquamation have followed repeated application. In
some cases, DEET has caused contact dermatitis and exacerbation of preexist-
ing skin disease. It is very irritating to the eyes, but not corrosive.
Serious adverse effects have occurred when used under tropical conditions,
when it was applied to areas of skin that were occluded during sleep. Under
these conditions, the skin became red and tender, then exhibited blistering and
erosion, leaving painful weeping denuded areas that were slow to heal. Per-
manent scarring resulted from most of these severe reactions.
