AbstractDecision‐makers in the protected crop environment face similar pest‐management decisions, in economic terms, to growers of field crops or grain store managers. As a result, the principles of economic thresholds, cost: benefit analyses and risk minimisation apply equally to each of these systems. Growers are faced with several general classes of pest‐control decisions: the general control strategy to adopt, and then tactical questions such as when to start control and when to stop or change control practices. However, there are a number of aspects of protected crops which require a somewhat different view of the problem. Several economic models for these questions are examined.The high density of protected crops means that a great deal is at risk at any one time. The protected environment reduces uncertainty about losses, but by optimising temperatures and humidities it increases the probability of loss. The feeling of being able to “control” the environment may extend to pests as well, increasing the use of standard pesticide or biocontrol programmes, rather than responsive pest management based on thresholds.The relatively small scale of protected crops, their accessibility for inspection and the high level of management skills involved in their production improve prospects for monitoring and predicting crop levels, insects and diseases, thus reducing uncertainty. However, the high probability of loss may reduce the value of gathering information, and encourage growers to rely on standard prophylactic procedures which allow them to devote management effort to more productive activities, such as marketing.The balance may be shifted towards more information‐based decisions in the future to try to avoid excessive pesticide use because of more stringent regulations on pesticide residues and changing market demand for more organic produce. This may affect disease control in particular, where prophylactic biological control is not an option.At the policy level, feedback on environmental impacts to consumers and policy‐makers is poor and decisions with expensive implications for the economy and for environmental quality may not be made in an o
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