Agricultural insecticides

Free naphthenic acids are corrosive and are mainly used as their salts and esters. The sodium salts are emulsifying agents for preparing agricultural insecticides, additives for cutting oils, and emulsion breakers in the oil industry. 

Satisfactory figures on the annual expenditure by growers for insecticides are not available. This varies from season to season, depending on several factors in addition to the intensity of insect infestations. It has been estimated that for the calendar year 1934 farmers and others paid about 25,000,000 for the more commonly used insecticides for the same materials the cost in 1948 would have been approximately 28,000,000. During this 14-year interval the use of agricultural insecticides had more than doubled. The estimated expenditure for insecticides in 1948 approximated 60,000,000. Interest in and appreciation of the benefits of insect control are thus apparent. 

Colorless to pale-yellow, oily liquid with a "faint" odor. Commercial product is a mixture of cis and trans isomers. This material is hazardous through inhalation, skin absorption, penetration through broken skin, and ingestion, and produces local skin/eye impacts. Used as an agricultural insecticide. 

Pyrethroids for agricultural use were developed in the 1970s in Japan, USA, and Europe after research on photostable synthetic pyrethroids. Those compounds were composed of an acid moiety obtained by various modifications and a chemically stable alcohol component, such as benzyl group and m-phenoxybenzylalcohol. According to recent statistics, pyrethroids accounted for approximately 20% in value of agricultural insecticides used annually all over the world in 2009. 

Modification of the Alcohol, Acid, and Ester Linkage (Pyrethroid-Like Compounds) Agricultural Insecticides and Termiticides... 

Insect resistance and environmental pollution due to the repeated application of persistent synthetic chemical insecticides have led to an Increased interest in the discovery of new chemicals with which to control Insect pests. Synthetic insecticides, including chlorinated hydrocarbons, organophosphorus esters, carbamates, and synthetic pyrethroids, will continue to contribute greatly to the increases in the world food production realized over the past few decades. The dollar benefit of these chemicals has been estimated at about 4 per 1 cost (JJ. Nevertheless, the repeated and continuous annual use in the United States of almost 400 million pounds of these chemicals, predominantly in the mass agricultural insecticide market (2), has become problematic. Many key species of insect pests have become resistant to these chemicals, while a number of secondary species now thrive due to the decimation of their natural enemies by these nonspecific neurotoxic insecticides. Additionally, these compounds sometimes persist in the environment as toxic residues, well beyond the time of their Intended use. New chemicals are therefore needed which are not only effective pest... 

Consider the following purely hypothetical example assessment for the exposure of an insectivorous bird to a new agricultural insecticide. This insecticide degrades very quickly after application, so that its toxicity dissipates after 24 hours. It does not bioaccumulate, and nonlethal doses are metabolized with no long-term consequences for the bird. These features imply a fairly simple assessment, involving the following expression for computing exposure of a bird to the insecticide within 1 day of its field application... 

The pyridine alkaloids anabasine (1), nicotine (2), ricinine (3), nomicotine (4) and trigonelline (5) form an important group of natural products. Thus anabasine (1) is extracted on a large scale in the Soviet Union (56MI20900) and functions as an insecticide with acute and subacute toxicity. Nicotine (2) has been used as an anthelmintic but more widely as an agricultural insecticide, functioning as a contact poison when combined with oleic acid... 

Substituted phenyl N-methylcarbamates (ArOCONHMe) are one of the most widely used agricultural insecticide classes which inhibit acetylcholinesterase (AChE). The steps by which they react with AChE are shown in Eq. 13, where EOH denotes the enzyme. 

An agricultural insecticide contains 18% arsenic. Express this as the percentage AS2O5. 

DDT is available and used in different formulations (e.g., aerosols, dustable powders, emulsifiable concentrates, granules, wettable powders). It is used mainly to control mosquito-borne malaria. Its use on crops has decreased because of its persistent residues. DDT was extensively used during World War II among Allied troops and certain civilian populations to control insect typhus and malaria vectors, and was extensively used as an agricultural insecticide after 1945. DDT was banned for use in Sweden in 1970 and in the United States in 1972. In view of its large-scale use over the decades, many insect pests may have developed... 

Fig. 12.6 Basic structures of organophosphate AChE inhibitors. X represents the leaving group, (a) Typical agricultural insecticides (b) typical chemical warfare agents.

The former is a photostable and efficient agricultural insecticide having no cyclopropane ring that is employed for cotton, fruits and vegetables. 

Sulfur is quite versatile it can be used as an agricultural insecticide or as a raw material for making sulfuric acid, as shown in Figure 2.12. To make sulfur, acid gas (hydrogen sulfide, sulfur dioxide, and carbon dioxide) from the various refinery amine units is collected and fed to a sulfur plant. In a typical sulfur plant, the acid gas is fed to a reaction furnace. The hydrogen sulfide is first partially burned at 2,500° F (1,370° C) and 15 psia (103 kPa) in the reaction furnace to form sulfur dioxide next, it is passed through a waste heat boiler and then passed over catalyst beds at 500°F (260° C) and 15 psia (103 kPa) in the converters. Sulfur is condensed from the effluent of successive converters and solidified in pits. 

Has a monoester content of 50-60%, free glycerol 1%, and moisture 1%, maximum. It is used as a component in mold release agents, a vehicle for agricultural insecticides, an anti-icing fuel additive, and a rust preventive additive for compounded oils. It is used in the textile industry as a lubricant component in synthetic fiber spin finishes. 

Insecticides are the pesticides most commonly known by the public. Insects are not only a nuisance in everyday life they pose a real danger to man, animals, crops, and the environment in general. In agriculture, insecticides are used widely to control insects in fruits, vegetables, rice, and other cereals. Other application areas are on farm animals, animal housing, and to control insects that are vectors of diseases. Mosquitoes (for malaria) and tsetse flies (for sleeping sickness) are just two examples. Control of these insects is a never-ending task, especially in hot and humid countries. 

---