Insecticides market

Synthetic pyrethroids now account for at least 30% of the world insecticide market and are rapidly replacing other agricultural chemicals for control of insect pests. Fenvalerate is one of the more widely used synthetic pyrethroid insecticides. It is derived from a combination of a-cyano-3-phenoxybenzyl alcohol and a-isopropyl phenylacetate ester. Technical fenvalerate is a mixture of four optical isomers, each occurring in equal amounts but with different efficacies against insect pests. Fenvalerate does not usually persist in the environment for >10 weeks, and it does not accumulate readily in the biosphere. Time for 50% loss (Tb 1/2) in fenvalerate-exposed amphibians, birds, and mammals was 6 to 14 h for reptiles, terrestrial insects, aquatic snails, and fish it was >14 h to <2 days and for various species of crop plants, it was 2 to 28 days. Fenvalerate degradation in water is due primarily to photoactivity, and in soils to microbial activity. Half-time persistence in nonbiological materials is variable, but may range up to 6 days in freshwater, 34 days in seawater, 6 weeks in estuarine sediments, and 9 weeks in soils. 

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... 

Table 1.4 Estimated share of world insecticide market...

In the last year a new formulation of aminocarb has appeared on the insecticide market. It is finely ground aminocarb suspended in an oil and it has the advantage that it can be tank mixed to give either an oil or a water suspension. Studies (10) show that, like the oil solution, this product has a half life in the same range (3.2 to 6.0 days). There was an indication of a variation in the initial rate of loss due to the physical characteristics of the water emulsion spray (in a series of repeat studies the evaporation rate was not constant). The presence of the emulsifier inhibited evaporation resulting in a higher initial foliar deposit than with the oil base spray. The occurence of the lower rate of deposit of the oil spray can be attributed to the particular oil used in the Canadian budworm sprays. To meet the concerns of the health authorities the standard No. 2 and No. 4 fuel oils which had been used are now prohibited. The accepted product, known as Insecticide Diluent 585 is volatile with an evaporation rate approaching that of water. 

Traditionally, the discovery process begins when a chemist synthesizes a new compound. The chemist may choose to make compounds based on an understanding of vertebrate pharmacology, biologically active natural products, or proven insecticidal chemistry or he may choose to make completely novel structures for which no biological information is available. In any case the compounds are evaluated for toxic effects in insect species which usually represent desirable insecticide markets. The objective of this initial testing is to eliminate inactive compounds from further tests, and to roughly define the species spectrum of activity. 

Optically active and biodegradable deltamethrin6 4 has taken a large share of the insecticide market, and asymmetric hydrogenation is used in the commercial synthesis of DOPA 5 used to treat Parkinson s disease.7 These achievements depend both on the development of new methods and on strategic planning 8 the twin themes of this book. 

Research on control failures during the late 1970 s and early 1980 s focused on carbofuran, a compound that had earlier provided excellent control and had captured a considerable share of the rootworm insecticide market (e.g. 20% of treated acres in Iowa in 1977)(9). Although some studies found no correlation between prior use of carbofuran and an enhanced rate of carbofuran degradation (10.11) both monitoring of field residues (12-14) and laboratory degradation tests (15-17) conclusively demonstrated enhanced microbial degradation as the cause of decreased carbofuran persistence in fields with histories of carbofuran use. Thus, a... 

Therefore, although little mineralization of the carbofuran ring occurred in any soil, there was a tremendous accumulation of soil-bound residues in the soil in which carbofuran was rapidly degraded. The enhanced degradation of carbofuran has been extensively documented (18). The behavior of cloethocarb was similar to that of carbofuran, and it too was extensively degraded in the history versus the nonhistory soil with substantial accompanying production of soil-bound residues. Cloethocarb is a carbamate insecticide that was under development for the rootworm insecticide market but was withdrawn about the same time that decreased persistence in soil after repeated use was noted (28). 

Both isofenphos and fonofos were much less persistent in the history versus the nonhistory soils. A major difference between these insecticides and the carbamates was that considerable mineralization of the aromatic ring portion of the organophosphorus compounds occurred. For Isofenphos, considerable quantities (15.2/0 of isofenphos oxon accumulated only in the nonhistory, whereas no such accumulation was noted in the isofenphos-history soil. Several reports of the reduced persistence of isofenphos in field plots following repeated use have appeared (29.30). and isofenphos was withdrawn from the rootworm insecticide market after widespread experiences of control failure following second year applications. This is especially ironic because upon first application to soil isofenphos behaves as one of the most persistent organophosphorus insecticides (31). 

The Midwestern U.S. rootworm insecticide market (>200 MM /year) supplies a litany of lost business and failed products. Products removed from this market or halted In late stages of development at least partially as a result of enhanced degradation Include fensulfothion (Chemagro), bufencarb (Chevron), bendiocarb (Fisons), cloethocarb (BASF), trimethacarb (Shell), and Isofenphos (Mobay)... 

To conclude to a more realistic amount of the health cost assessment results of the study of Whangthongtham (1990) are used to calculate poisoning cases in relation to insecticide market volume. The poisoning cases per hectare and the intensity of insecticide use are needed for this calculation. Firstly the reported poisoning cases are mainly due to insecticide use and are therefore related to the quantity of insecticides used. Secondly, poisoning cases are not location specific and finally, the hazardousness of the pesticides used is comparable for all crops. 

Acetylcholinesterase is by far the most widely used enzyme in the preparation of biosensors for determining pesticides, both because organophosphorus insecticides and carbamates represent over half of the entire insecticide market and because the acetylcholinesterase commercially available has a high degree of purity and specificity of action and may be paired with many transducers (potentiometric, amperometric) in both flow and nonflow systems [62]. The specific tendency of organophosphorus pesticides and carbamates to inhibit acetylcholinesterase has been exploited for the purpose of determining these compounds, which are first separated by means of HPLC, then detected through a post-column reaction with immobilized acetylcholinesterase [63]. 

Figure 24.1 shows the major insecticidal classes and their market share in 2003. The global insecticide market is forecast to decline in value by 1.3% per annum until 2007. This represents a fall in the overall agrochemical market share from 27.5% in 2002 to 25.7% in 2007 [15]. 

The achiral etofenprox (25 X = O, A = carbon R = OEt) containing no halogen atom shows a non-ester exerting pyrethroid-like efficacy and is highly advantageous regarding the rice insecticide market (Table 35.5). 

Given the disadvantages mentioned before, the manufacture of chrysanthe-mic acid is economically less important than that of permethric acid. Scientifically, the syntheses of both compounds are ofinterest. The aim of (mostly industrial) research was to identify the simplest and cheapest way to access this structurally demanding class of substances. Nowadays, pyrethroid research is however largely a matter of the past, the insecticide market is dominated by... 

Minor structural variations led to nitenpyram, the second neonicotinoid on the insecticide market. 

Neonicotinoid insecticides have experienced a most remarkable and steady increase in use since their market introduction in 1991, now exceeding 10% of the total insecticide market 1-3). An overview of these products is given in Table I (cf. 4). The major advantages of the new products over the previously preferred organophosphates are a novel chemistry, a new mode of action, systemic action and human safety. The systemic activity makes them the insecticide class of choice for the control of plant sucking pests. 

In contrast, the neonicotinoids are not protonated and therefore bind differently, resulting in greater activity on insects than manunals. It is this selective toxicity that has led to extensive use of the neonicotinoids and they represent about 20% of the global insecticide market [34]. Worldwide sales of neonicotinoid insecticides are estimated at 1 billion [35]. Imidacloprid and thiacloprid are examples of neonicotinoid insecticides. 

The outline of the environmental health business is shown in Table I. This field includes indoor consumer products such as household insecticides, outdoor consumer products such as those for pest control, and public-health related products for mosquito abatement and professional vector control. All these products are required to have superior safety characteristics. The size of the world market for the environmental health business in terms of retail sales is also shown in Table I. The market size is estimated to be roughly 7.2 billion dollars overall, of which about 70%, or 5.0 billion dollars, represents the indoor use insecticide market. The size of the outdoor use insecticide and public health insecticide markets is 1.4 billion and 800 million dollars, respectively. 

Dr. Ran it Ghosh was developing new pesticides at Imperial Chemical Industries (ICI). He synthesized a new and very potent insecticide, marketed as Amiton (VG) in 1954. Unfortunately, it was so potent that it was lethal to humans, with a toxicity similar to Sarin, and was rapidly removed from the market. 

It is estimated that 45-50 billion mosquito coils are used annually by approximately 2 billion people worldwide, mainly in Southeast Asia, but with a growing market in South America and Africa. Mosquito coils were traditionally made with finely groundpyrethrum daisy Chtysanthemum cinerariaefolium) flowers mixed with coconut husks or sawdust. Synthetic pyrethroids, based on the molecular structure of the pyrethrins contained in the pyrethrum daisy, have outstripped natural pyrethrins for use in household pesticides because they are far more photo stable, although both chemical groups possess rapid insecticidal and repellent action. Nonetheless, 17,000 tons of natural pyrethrum are produced in Kenya, Tanzania, Rwanda, and Australia annually to supply the household insecticide market. There is ample evidence that mosquito coils made from both natural pyrethrins and synthetic pyrethroids effectively repel mosquitoes. ... 

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