Pest control allelochemicals

How to deal with the pests that attack plants under cultivation is a continuing challenge to the food and agricultural production system. Natural resistance or tolerance to pests has proven to be one of the safest and least costly ways to protect plants. As we identify the specific plant components involved and their actions, it will be easier to incorporate the capacity to produce the desired chemical into the plant of Interest. There is the further possibility to identify additional natural chemicals that may be useful as pest control materials. The latter might be through the use of natural products or it might be products of industrial synthesis patterned after the natural products. It is clear that allelochemicals are involved in these complex processes and they hold promise for even a greater role. 

Rice, E. L. "Pest Control with Nature s Chemicals Allelochemicals and Pheromones in Gardening and Agriculture" University of Oklahoma Press Norman, 1983. 

Multipurpose pesticides. Occurrence of more than one pest-controlling property in a single allelochemical has persuaded us to propose using allelochemicals as multipurpose pesticides (IS). Such use would be beneficial in several ways ... 

Dicke, M., Sabelis, M. W., Takabayashi, J., Bruin, J. and Posthumus, M. A. (1990a). Plant strategies of manipulating predator-prey interactions through allelochemicals prospects for application in pest-control. Journal of Chemical Ecology 16 3091-3118. 

Higher plants have evolved an extraordinary variety of secondary metabolic pathways, the resulting products of which have been put to use by man providing pharmaceuticals for drug use, insecticides and various allelochemicals for pest control, and extracts for the flavor and fragrances industries. In spite of advances in synthetic organic chemistry, plants remain a major source of natural products, particularly in the specialty chemicals industry. Compounds, such as the insecticide derived from Azadiraohta indioa or the antitumor alkaloids vinblastine and vincristine found in periwinkle (Catharanthus roseus) (1 ), have complicated structures which preclude at the present time the development of an economical chemical synthesis (Figure 1). In the case of... 

DICKE, M., SABELIS, M.W., TAKABAYASHI, J., BRUIN, J., POSTHUMUS, M.A., Plant strategies for manipulating predator-prey interactions through allelochemicals Prospects for the application in pest-control, J. Chem. Ecol., 1990, 16, 3091-3118. 

Lit. ACS Symp. Ser. 658, Phytochemicals for Pest Control (1997) Agosta, Bombardier Beetles and Fever Trees, New York Addison-Wesley 1995 Chem. Ind. (London) 1994, 370ff. Eur. J. Org. Chem. 1998, 1479 (review) Norland, Jones, Lewis, Semiochemicals, their Role in Pest Control, New York Wiley 1981 Rice, Pest Control with Nature s Chemicals Allelochemicals and Pheromones in Gardening and Agriculture, Norman Univ. Oklahoma Press 1983. 

Rice EL (1983) Pest control with nature s chemicals allelochemics and pheromones in gardening and agriculture. University of Oklahoma Press, Norman, OK Rice EL (1984) Allelopathy. Academic Press, Orlando, FL... 

Dicke M, Bruin J (2001) Chemical information transfer between plants back to the future. Biochem Syst Ecol 29 981-994 Dicke M, Dijkman H (2001) Within-plant circulation of systemic elicitor of induced defence and release from roots of elicitor that affects neighbouring plants. Biochem Syst Ecol 29 1075-1087 Dicke M, Sabelis MW, Takabayashi J, Bruin J, Posthumus MA (1990) Plant strategies of manipulating predator-prey interactions through allelochemicals prospects for application in pest control. J Chem Ecol 16 3091-3118 Dicke M, Takabyashi J, Posthumus MA, Schiitte C, Krips OE (1998) Plant-phytoseiid interactions mediated by prey-induced plant volatiles variation in production of cues and variation in responses of predatory mites. Exp Appl Acarol 22 311-333... 

The overuse of synthetic chemicals for pest control is a threat to the environment (22-23). There is a misleading tendency that compounds produced by plants are eco>friendly. In fact, many allelopathy researchers feel that allelochemicals could be ideal agrochemicals (24-33). But we must assess the safety of these products before using allelochemicals just the same way as synthetic agrochemicals. 

Others also have proposed that allelochemicals could prove useful in crcp protection, especially for minimizing the agricultural losses due to insects and nematodes, and for controlling diseases. The USDA Research Planning Conference in 1977 estimated that technological advances could reduce substantially the 30 billion in annual losses caused by pests and the cost of their control (37). This conference proposed the following strategies for research Tn allelopathy. 

Yu SJ (1989) Purification and characterization of gluathione S-transferase from five phytophagous Lepidoptera. Pestic Biochem Physiol 35 97-105 Yu SJ (1992) Plant allelochemical-adapted glutathione transferases in Lepidoptera. In Mullin CA, Scott JG (eds) Molecular mechanisms of resistance to herbivorous pests to natural, synthetic and bioengineering control agents. Plenum, New York, pp 174-190 Yu SJ (1996) Insect glutathione S-transferases. Zool Stud 35 9-19... 

A better understanding of the role of phytoalexins in plant defenses and of the mechanisms of induced resistance may potentially open a powerful new approach to the control of insect pests of cultivated plants. If indeed, in light of the hypothesis of optimal defense strategies (3), a post-attack response is a more efficient line of defense than the attack-independent accumulation of allelochemics, the exploitation of phytoalexin-producing mechanisms may represent a fertile field for future investigations. Several uses of induced resistance may be conceived. Four of these approaches are briefly discussed. 

In this chapter the different roles that allelopathy can play as a bioregulator tool in agriculture are discussed. A wide spectrum of studies are given on allelopathic plants and other organisms, the chemistry involved in these studies, the mechanisms of action of some allelochemicals, and the use of allelopathy to control weeds, pests (nematodes) and diseases. 

Chapters 2 and 9-20 in this volume discuss the control of insects with allelochemicals, and the mechanisms by which plants biosynthesize these compounds and use them to become resistant to their pests. 

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