the GlobalChangeBiology blog

 Coffee, after petroleum, is the most valuable commodity globally in terms of total value (harvest to coffee cup). Here, our bioeconomic analysis considers the multitude of factors that influence coffee production. The system model used in the analysis incorporates realistic field models based on considerable new field data and models for coffee plant growth and development, the coffee/coffee berry borer (CBB) dynamics in response to coffee berry production and the role of the CBB parasitoids and their interactions in control of CBB. Cultural control of CBB by harvesting, cleanup of abscised fruits, and chemical sprays previously considered are reexamined here to include biopesticides for control of CBB such as entomopathogenic fungi (Beauveria bassiana, Metarhizium anisopliae) and entomopathogenic nematodes (Steinernema sp., Heterorhabditis). The bioeconomic analysis estimates the potential of each control tactic singly and in combination for control of CBB. The analysis explains ...

Control of insect pests and other taxa may be due to many factors that are difficult to separate and quantify as was the case for the control of the spotted alfalfa aphid (SAA, Therioaphis maculata Monell) in California and elsewhere. Introduced parasitoids, host plant resistance, pathogens and native predators led to its successful control, but the relative contribution of each factor remained largely unknown. The relative contribution of each control factor was estimated using a weather-driven physiologically-based demographic system model consisting of alfalfa, SAA (a), its three exotic parasitoids [ Trioxys complanatus (Quilis) (b), Praon palitans Muesebeck (c), and Aphelinus semiflavus Howard (d)], a native coccinellid beetle [ Hippodamia convergens (Guérin-Menéville)], a fungal pathogen [ Erynia neoaphidis Remaudière & Hennebert (Zygomycetes: Entomophthorales) (g)], and host plant resistance (HPR) (h). Alone, each factor failed to control SAA, as did combinations of the ...