Plant-pest interactions

Fomsgaard, I.S. (2006) Chemical ecology in 131. wheat plant-pest interactions. How the nse of modem techniques and a multidisciplinary approach can throw new light on a well-known phenomenon Allelopathy. J. Agric. 132. Food Chem. 54, 987 990... 

The specific function of many phytochemicals is still unclear however, a considerable number of studies have shown that they are involved in the interaction of plants/pests/diseases. Most plants produce phytochemicals as anti-microbial, antibiotic, insecticidal and hormonal agents either as part of... 

Pathogen attack The induction of LOX genes during plant-pathogen interactions has been reported in several species, suggesting that the function of LOX in the defense against pests seems to be related to the synthesis of a number of different compounds with signaling functions or antimicrobial activity. 

Alexander, H.M. Dynamics of plant-pathogen interactions in natural plant communities. In Pests, Pathogens and Plant Communities. Burdon J.J. and Leather S.R. eds., Oxford, UK Blackwell Scientific Publications 1990. 

Figure 2 depicts just some of the known response-stimulus relationships for plant pests. Collection of the fundamental data and description of the responses with mathematical models can lead to a better understanding of pests in the field. If one knew the current environmental conditions, one could predict whether or not the potato leafhopper would increase during the next week. Final decisions would also be based on the known population dynamics of the pests of interest (see below), as well as the known interaction between the plant host and pest. 

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... 

Beyond understanding plants/pest insect interactions, chemical ecology can help design more environmentally friendly crop protection methods. The VOCs emitted by plants are key mediators in the search and use of resources by predators and parasitoids (see Chapter 9, particularly Figure 9.4). Indeed, these... 

Tetratrophic interactions between a host plant, a phytophagous pest (primary host), a hymenopteran parasitoid or symbiont (secondary host) and a hymenopteran hyperparasitoid (which parasitizes the secondary host) are of considerable importance, because hyperparasitism can significantly reduce populations of economically beneficial parasitoids [11]. Hyperparasitoids use host-marking (=spacing) pheromones, sex pheromones [12], and host-detection cues [42], but they also show additional chemically mediated interactions with the other partners. These include detection of the primary host s secretions by the hyperparasitoid [43], detection of plant volatiles by the hyperparasitoid [44], and detection of the hyperparasitoid s secretions by the primary host [45] or by the secondary host. The latter causes the secondary host to avoid locations where the hyperparasitoid is foraging [46]. 

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