Pests targeting pesticides

Pesticides are considered a necessary evil however, it has been estimated that without their use food expenditure for western families would more than double (Zilberman et al. 1991) and, much worse, food shortage would be more acute in many third world countries about 40% crop production would be lost, according to FAO. Pest and pesticide control is probably the sector where a really integrated view of farm management is most required certainly, pest treatments by calendar as largely in use till a few years ago and still in use today here and there are unsustainable. The principles of targeting interventions according to real need as advocated... 

Integrated crop and pest management reduces inputs by applying fertiliser and water only as needed for crop growth and targeting pesticides at those weeds, pests and diseases actually present in the crop. 

One result of pesticide use is the growth in the number of target species ( pests ) that have become resistant to pesticides. From 1970 to 1984, the number of resistant arthropod species doubled - from 224 to 447. These include 25 species of beetles, mites, and caterpillars that attack... 

Another important result of the appearance of resistant target species is the increase in the number of pesticides to which pests acquire resistance. Resistance develops to all the pesticide groups used (Table 5.2). 

If the rate at which resistance appears is maintained, all 2000 main species of weeds and pests will become resistant to the pesticides used in 30-40 years. If the biosphere s pesticide exposure doubles, by 2015-2020, all target species could become universally resistant. But with such chemical contamination, pesticides would then affect the entire biosphere, including human health. 

Tables 14.6, 14.7, 14.8, 14.9 and 14.10 provide further insight into the comparative properties and toxicity of pesticides applied on organic and conventional farms to treat a given type of pest. Table 14.6 lists the primary pesticides approved for use on organic farms and their uses and target pests. Tables 14.7-14.10 again list the major organic pesticides, along with two or three conventional pesticide alternatives that are used by conventional farmers to manage the same pest problems. Tables 14.7 and 14.8 summarize the rates of application of these pesticides, while Tables 14.9 and 14.10 focus on relative measures of toxicity to mammals and other organisms.

Modem agriculture uses worldwide about 2.5 million tons of pesticides annually (Wijnands 1997), and out of such quantity only about 0.4% reaches the targeted pests, according to Pimentel (Pimentel 1995), while losses through volatilization are on the order of 80-90% (Taylor and Spencer 1990). 

Pimentel D (1995) Amounts of pesticides reaching target pests environmental impacts and ethics. J Agric Env Ethics 8 17-29... 

Mainly comprised of plant protection products and biocidal products, pesticides are designed to influence fundamental processes in living organisms. They may have the potential to kill or control harmful organisms such as pests, but can also cause unwanted adverse effects on non-target organisms, human health and the environment (EC 2007). Both the hazards and benefits of pesticides are well documented in published literature and have been reviewed most recently by Cooper and Dobson (2007). 

Since the last part of the 20th Century, the issue of pesticides in foods has generated considerable public concern and debate. Pesticides are chemicals designed specifically for their toxicological effects on target pests, such as insects, weeds, and plant diseases. Public awareness that such chemicals are commonly detected in the food supply as residues contributes greatly to the debate. 

Protecting garden friends Even organically approved pesticides are nonselective and will kill both harmless and helpful insects as well as the target pest. Always spray in the evening, when bees are not active, and never spray on a windy day when the pesticide might drift. 

Obviously it s. important to know as much as possible about the mode of action of pesticides on NON-target organisms if the differential between them (pest and non-pest) is to be maximized. 

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