Viewing Organic Field and Forage Crop Systems through the Integrated Pest Management (IPM) Continuum Paradigm.

Integrated pest management (IPM) has been described as a universal paradigm, which in practice becomes specific to the intended crop, site or situation. A key component of insect IPM in field and forage crop agriculture is pest monitoring prior to reaching a treatment decision.  Once an insect pest is known to be present and an actual or potential economic threat, an insecticide treatment decision can be made based on economic injury level factors (e.g., treatment cost, crop value, yield potential, relationship between insects per plant and yield loss, and proportion of control that can be achieved by treatment). Advancing along the IPM continuum, a crop systems approach relies principally on ecological and biological means to suppress pest populations. Under USDA National Organic Program (NOP) certification standards, organic growers rely on crop rotation, soil and crop nutrient management, pest resistant crop varieties, and biological control to suppress insect pests. Only when a combination of these practices fails to adequately suppress pests can an organically approved insecticide be applied. Three organic agriculture IPM approaches are examined here: First, evaluation of NOP-compliant insecticides for soybean aphid [Aphis glycines Matsumura] in soybeans [Glycine max (L.) Merr.] with efficacy data and developmental effects on soybean aphid, as well as non-target effects on its key predator, the multicolored Asian lady beetle [Harmonia axyridis (Pallas)]. Second, intercropping forage grass with glandular-haired alfalfa [Medicago sativa (L.)] to manage potato leafhopper [Empoasca fabae (Harr.)]. Third, impact of long-term organic soil and crop nutrient management on insect pest mitigation and natural enemy functional response in a grain crop/forage legume rotation. Conventional agriculture does not preclude sustainable systems for pest management. However, organic field and forage crop systems, with participatory input of organic farmer knowledge and increasing land grant university research investment, offer a fresh perspective on the IPM continuum.