Pathogens controlling strategies

This chapter will endeavor to condense a rather wide ranging subject into some basic principles regarding the types of chemicals used to control plant pathogens the strategies behind these and some thoughts on new approaches to the development and use of chemicals to control fungal diseases of plants. 

An important control strategy in the combat against extreme acid-tolerant food pathogens such as E. coli 0157 H7 is found in decontamination of meat carcasses. The ideal may be to control the extent of exposure of E. coli 0157 H7 to acid during meat processing and to increase the use of nonacid interventions such as hot water spraying and steam pasteurization, and would be a logical approach to sensitize E. coli 0157 H7 to acid in the absence of acid stress in food environments. Enhanced meat safety may be promoted by more intense use of water-based decontamination... 

Prions share the ability to propagate strain information with nucleic acid based pathogens, but it is unclear how they mutate and acquire fitness in the absence of this informational component. Because prion diseases occur as epidemics, understanding this mechanism is of paramount importance for implementing control strategies to limit their spread, and for evaluating their zoonotic potential. While the existence and mutability of strains persuaded early researchers that prion... 

The development of control strategies to reduce E. coli 0157 H7 will require the identification of biological, environmental, and/or management factors that affect its incidence in cattle and their production environments. Research investigations and epidemiological studies have identified a number of risk factors or management practices that can or may contribute to the occurrence of this pathogen, and that may be exploitable to reduce its numbers, persistence, and transmission in cattle. 

Buffer would be, in fact, a much better term for a biological control strategy because the objective is rarely the active eradication of a pest species or spectrum by application of a toxic compound, but rather the intent is to cushion the impact of a biological proliferation, i.e. the target pest population, and tip it towards economically acceptable, or threshold levels. Neither pathogens, behavioral disruptions nor induced predators will bring about the eradication of a pest species. They only serve to keep populations at levels compatible with local horticultural practices. Does that make them pesticides Yes, if we want to call them that. No, if we find it more advantageous not to. 

Despite the success of vaccines, their use in the absence of a comprehensive disease control strategy may allow the entry of other pathogens. This may well have happened with enteric redmouth (ERM) vaccines in rainbow trout whereby the apparent failure of a previously effective product in the UK heralded the arrival of what transpired to be a new biogroup of Y. ruckeri, biogroup 2 (Austin et al, 2005). A parallel situation occurred with Atlantic salmon culture in Tasmania whereby the standard ERM vaccine lost effectiveness, and led to an improved product involving the trypsinization of the component culture to expose the O-antigen and... 

The recently published book on food safety related to animal products Improving the Safety of Fresh Meat edited by Sofos (Sofos, 2005) is a very valuable resource that covers different strategies of control and understanding the ecology of pathogens transmitted via meat. Another book that covers the topic of farm-to-fork food safety with relevant information on livestock... 

Martin FN (2003) Development of alternative strategies for management of soilborne pathogens currently controlled with methyl bromide. Annu Rev Phytopathol 41 325-350. doi 10.1146/ annurev.phyto.41.052002.095514... 

Allelopathic compounds act as repellents for herbivorous pests, so the same strategy used in weed control could be effective against pests and pathogens. Only allelopathy is not possible to use the complete control of weeds, pests or diseases it is necessary to combine it with other methods of plant protection. 

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