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Biopesticides are attracting interest as alternatives to conventional pesticides but without many of the non-target effects, promising a better record of safety and sustainability in pest control practices. In this article we summarize and discuss the current status and future promise of biopesticides, including how biopesticides use may increase the quality and safety of the food supply.

The current knowledge about transformation rates and products of pesticides in the atmosphere is reviewed. Reactive species and their concentrations in the atmosphere are presented. Reactions of pesticides with these species (including photolysis) in the gas and the particulate phase are evaluated from available experimental data. The potential of estimation methods is discussed. Experimental techniques for laboratory and outdoor measurements are reviewed. Finally, an estimation is made of uncertainties in atmospheric lifetimes due to chemical or physical reactions. It is concluded that the most important transformation of pesticides in the atmosphere is due to reaction with OH radicals. Very few experimental data for pesticides are available though. The levels of uncertainty in OH radical concentrations are acceptable, however, for a proper estimation of atmospheric removal rates due to reactions with OH radicals of those pesticides for which experimental transformation rates (of homologues) are available.

This study examines the processes of dilution, degradation, and sorption to plant foliage of organophosphate (OP) pesticides during the summertime in an air corridor originating in the southern Central Valley of California and moving into the nearby Sierra Nevada mountains. Residues of chlorpyrifos, methidathion, and their oxons were examined in air and pine needles at three sites in the southern Sierra to delineate the role these processes play in the atmospheric fate of these residues. At the site closest to the Central Valley, we found relatively high levels of parent OPs and oxons in needle and air samples. At higher elevations needles contained lesser amounts of OP residues and at lower frequency, while air primarily contained the oxon form. With increasing elevation the ratio of thion to oxon form of chlorpyrifos in air decreased from 1.85 to 0.46 indicating that atmospheric oxidation was occuring. Based on the amounts of foliar deposition found, we estimate that during summer months nearly 16 kg of chlorpyrifos and its oxon may enter Sequoia National Park plant foliage. We deduce that for airborne OP insecticides, foliar deposition is a significant summertime fate process, along with atmospheric degradation and dilution.

Study of several new types of fungitoxic derivatives of imidazole reveals that imidazoles substituted on the imine nitrogen atom are likely to be active if the substituent is electron-attracting, and if the atom connecting it to the imidazolyl moiety has tetrahedral geometry. Fungitoxicity is high with phosphinamidothionate and triarylmethyl groups as substituents. The presence of an asymmetric phosphorus atom in the substituent has no effect on fungitoxicity, but affects mammalian toxicity.

This chapter appraises the transport and fate of pesticides in the environment. Significant advances have been made in defining and understanding the principles that underlie pesticide dissipation in the environment. It is a goal of environmental sciences to understand and deal with the complexities in nature by defining and sorting out underlying principles. These can serve as a basis for developing an assessment of chemical processing and its relationship to the health of the environment. This has led to better testing procedures and better environmental fate models, which in turn have given rise to better methods for predicting environmental behavior or fate before use or release occurs. Because of the complexity in the environment, and even in parts of the environment such as a pond, a cross-section of soil, or vegetation in contact with the atmosphere, environmental scientists have developed models for studying and for predicting or estimating transport and fate processes. There are two broad classes of models—physical models and mathematical or arithmetic models. The development of a predictive capability has helped focus efforts in industry and agencies toward marketing and regulating safer chemicals and restricting or eliminating those that are likely to pose significant risks, in many cases early in the development stage and before widespread use occurs.

Asclepias speciosa and A. curassavica were evaluated as potential renewable sources of chemicals for use as fuel and/or chemical feedstock. Leaves and stems of both plants were analyzed for acid-detergent fiber, acid-detergent lignin, cellulose and ash. Bomb calorimetry was performed on A. curassavica (leaves 4,590 cal/g; stems 4,219 cal/g; and latex 4,663 cal/g), and A. speciosa (leaves 4,404 cal/g; stems 4,514 cal/g; and latex 9,005 cal/g). Organic carbon in A. curassavica (leaves 41.20%; stems 41.18%; latex 48.03%) and A. speciosa (stems 45.71%; leaves 42.51%; latex 67.30%) were also determined. Major differences between the 2 plant species were in the chemical composition of the latex; A. speciosa latex contained primarily α- and β-amyrin and their acetates, and a small amount of rubber, while A. curassavica latex is known to contain at least 50% cardiac glycoside.