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Title: IPM for fresh-market lettuce production in the desert southwest: the produce paradox

item PALUMBO, JOHN - University Of Arizona
item Castle, Steven

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2009
Publication Date: 10/19/2009
Citation: Palumbo, J.C., Castle, S.J. 2009. IPM for fresh-market lettuce production in the desert southwest: the produce paradox. Pest Management Science. 65:1311-1320.

Interpretive Summary: The growth in the organic produce market is one example of how public interest in healthy food choices free of pesticide residues has increased in recent years. Nonetheless, there is still an expectation by consumers that their store-bought produce will be as aesthetically appealing as it is nutritious. Large-scale produce production in the desert southwest is subject to heavy insect pest pressure that often requires intensive pesticide treatments to prevent damages associated with insect infestations. It is therefore paradoxical for consumers to expect aesthetically perfect produce free of pesticide residues given the circumstances of constant pest attack. Although an economic threshold-driven IPM program could effectively manage pest populations and prevent serious damage, it cannot guarantee zero infestation and/or damage. This article discusses some of the challenges that originate in the marketplace, but have important ramifications for how pest management is practiced. In particular, these challenges are considered in the context of the integrated control concept that provided the theoretical foundation for modern IPM.

Technical Abstract: In the Integrated Control Concept, Stern et al. strongly emphasized that although insecticides are necessary for agricultural production, they should only be used as a last resort and as a compliment to biological control. They argued that selective insecticide use should only be attempted after it has been determined that insect control with naturally occurring biotic agents is not capable of preventing economic damage. However, they concluded their seminal paper by emphasizing that integrated control will not work where natural enemies are inadequate or where economic thresholds are too low to rely on biological control. Thus, it is no surprise that insect control in high-value, fresh-market lettuce crops grown in the desert southwest have relied almost exclusively on insecticides to control a complex of mobile, polyphagus pests. Because lettuce and leafy greens are short-season annual crops with little or no tolerance for insect damage or contamination, biological control is generally considered unacceptable. High expectations from consumers for aesthetically appealing produce free of pesticide residues further forces vegetable growers to use chemical control tactics that are not only effective but safe. Consequently, scientists have been developing integrated pest management (IPM) programs for lettuce aimed at reducing the economic, occupational, and dietary risks associated with chemical controls of the past. Most of these programs have drawn upon the Integrated Control Concept and promote the importance of understanding the agroecosystem, and the need to sample for pest status and use action thresholds for cost-effective insect control. More recently, pest management programs have implemented newly developed, reduce-risk chemistries that are selectively-efficacious against key pests. This paper discusses the influence that the Integrated Control Concept, relative to zero-tolerance market standards and other constraints, has had on the adoption of pest management in desert lettuce crops.