Climate and biological control in organic crops

Effects of CO2 and Temperature on Tritrophic Interactions

“…Experiments on simple tritrophic systems that include controlled manipulations of multiple variables that are changing globally provide data that allow for considerable insight into basic questions about the regulation of herbivore populations. More experiments, coupled with observational data and models, will help clarify the conditions under which factors like connectance, parasitism, herbivore, outbreaks, and ecosystem services will increase or decrease in response to interacting climate change variables [8]–[28]. Furthermore, understanding relationships between global climatic changes and tritrophic interactions is particularly important in agricultural systems, where herbivore outbreaks are predicted to increase.…”

“…Similarly, the majority of ecological climate change studies examine effects of single climate change variables on biological systems, but some studies have examined interacting effects of different global change parameters, such as increased CO 2 and increased temperature, on species interactions or on entire biotic communities [23]–[30]. Nevertheless, the theoretical framework for studying climate change and biotic interactions is still underdeveloped [4], [31]–[33] and there are insufficient numbers of empirical studies to effectively guide theory or synthesis [20], [28]–[30]. Existing studies have revealed that the effects of interacting global change parameters on trophic interactions are variable, especially for upper trophic levels, and more studies are necessary to determine factors that alter responses of biotic interactions to climate change [29].…”

“…High temperatures (and extreme weather events) can have direct negative effects on survival of natural enemies, such as parasitic wasps [7], [10], [35]–[37], which are particularly sensitive to any temperature changes [21], [22]. One such negative effect of increased temperatures and heat waves is an increase in parasitoid development times [10], [28]. Elevated temperatures can also decrease larval development time [14], [30], [38], [39] and increase performance [30].…”

“…The studies that have examined effects of climate change on tritrophic interactions [10], [12], [19], [25], [28], [29], [34], [56] suggest that effects on these interactions will favor outbreaks in natural and managed ecosystems, including most agriculture. Most notably, increases in climatic variability and extreme weather events associated with climate change disrupt regulation of herbivores by predators and parasitoids [7], [10], [57], [58].…”

Diseases in tropical and plantation crops as affected by climate changes: current knowledge and perspectives

“…There is almost no information on the impact of climate change on biological control of plant disease (Ghini et al, 2008a). Stacey (2003) discussed evidence of the effects of climate change on biological control agents (entomopathogens, predators and parasitoids) of pests. The few results obtained focus on the impact of climate change on the composition and dynamics of the microbial community of the phyllosphere and the soil, which can be very important for plant health (Rezá cová et al, 2005;Kanerva et al, 2006;Lagomarsino et al, 2007).…”