Pesticide biochemical

They are somewhat controversial with regard to their green credentials among some members of the public, the scientific community, and even other federal agencies [30-32]. They also are assessed for risk and regulated somewhat differently from either conventional chemicals or the other two categories of biopesticides [29]. 

Any pesticidal property expressed by a particular species theoretically could be engineered into, and expressed by, an entirely unrelated plant species, thereby creating a new PIP. 

For a substance or a mixture of substances to be classified as a biochemical pesticide active ingredient, three criteria must be met [33]  

1) It must be naturally occurring or, if not naturally occurring, it must be structurally similar to and functionally identical with a naturally occurring substance. 

2) It must have a nontoxic mode of action against the target pest. 

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Biochemical Pesticides Green Chemistry Designs by Nature... 

Biochemical pesticides include all naturally occurring substances (or their structurally similar synthetic analogs) that are intended for use as attractants, repellents, desiccants, semiochemicals, plant and insect regulators, and induced systemic response (ISR) and systemic acquired response (SAR) inducers. 

Biochemical pesticides thus include many synthetic analogs of naturally occurring substances that can be used to manage pests with little or no impact on human health or the environment. 

The USEPA considers the term nontoxic, with respect to the mode of action, to imply that no chemical or biological interaction of the biopesticide molecule occurs with the physiology of the target pest organism such that direct lethality results to that pest organism. Lethal effects, when they occur, are always downstream from the initial exposure to the biochemical pesticide and are typically the result of physicochemical processes,... 

Although not limited to these uses, the following modes of action are considered to be nontoxic for classification of a substance as a biochemical pesticide ... 

Insect growth regulation, suffocation, and desiccation as modes of action have been discussed above. The following briefly discusses the other nontoxic modes of action typical of biochemical pesticides. 

Are Biochemical Pesticides the Wave of the Future 341 Table 12.1 New pesticide active ingredients registered in fiscal year 2006 by USEPA/OPPa). 

The existing techniques used to screen conventional chemicals, however, may not be adequate to support the discovery of new biopesticides, particularly biochemical pesticides. Non-traditional approaches for new compound discovery may be needed. The potential for the discovery of new naturally occurring... 

The discovery of brassinolide by scientists at USDA led to the development of a new group of plant growth substances, termed brassinosteroids, which have the potential for increasing crop yields and biomass. The chapter summarizes the USDA s contributions to brassinosteroids, which include isolation and identification of brassinolide, synthesis of brassinolide and its analogs, and limited biological and field studies on brassinosteroids. An overview of the current data requirements for the registration of brassinosteroids as biochemical pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act is presented. 

Biochemical Pesticides. The characteristics noted above were not specified as being all of the attributes that a biorational pesticide might exhibit, nor was a biorational pesticide required to exhibit all of the cited characteristics. Proposed SS 158.165(a) (3) noted that EPA would make case-by-case decisions on what was or was not a biochemical-type biorational pesticide. This provision was included so that chemicals which are substantially similar to biochemicals but might not technically meet the two criteria established for defining biochemical pest control agents might be none-the-less classified as biochemical pesticides. 

The proposed criteria for a biochemical pesticide were, however, changed in the final regulation. In the current 158.165 regulation a biochemical pesticide is defined simply as follows ... 

Biochemical pesticides include, but are not limited to, products such as semiochemicals (e.g., insect pheromones), hormones (e.g., insect juvenile growth hormones), natural plant and insect regulators, and enzymes. When necessary the Agency will evaluate products on an individual basis to determine whether they are biochemical or conventional chemical pesticide. ... 

Brassinosteroids as Safer Pesticides. As stated above, for classification of chemicals as biochemical pesticides, the EPA considers the following criteria (a) natural occurrence, (b) low use volume, (c) unique mode of action, and (d) target species specificity. Brassinosteroids would meet the criteria set by the EPA for biochemical pesticides because of the following reasons ... 

Brassinosteroids, therefore, would qualify for classification as biochemical pesticides. Once they are classified as biochemical pesticides, the data requirements for U.S. registration would be significantly reduced (because of a tier approach), especially in the areas of toxicology, ecology and wildlife, and environmental fate. Because of their low use volume, brassinosteroids are unlikely to leave any residues in crops, and they would qualify for exemption from the requirement of a tolerance. If that were the case, what applicants seeking U.S. registrations need to do is to develop data on product chemistry and acute toxicology, as well as use profiles for their products, which will be dealt with on a case-by-case basis. 

In conclusion, we suggest that the applicants approach the EPA for classifying brassinosteroids as biochemical pesticides. They save time as well as the costs for developing the required data for registration of the products derived from brassinosteroids. 

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