When should control measures be initiated according to the economic threshold level?

Initiating control measures based on the economic threshold level is crucial for effective pest management. The economic threshold is defined as the pest population density at which the cost of pest control equals the economic loss caused by the pests. By acting when the pest population exceeds a specified number per plant, you are applying a preventive approach that is both economically sound and environmentally responsible.

This proactive action helps to maximize yield and minimize potential losses, ensuring that pest control measures are implemented before the pest population reaches a level that would cause significant economic damage to the crop. It emphasizes the importance of monitoring pest populations regularly and applying control measures at the optimal time, preventing unnecessary costs and maintaining sustainable agricultural practices.

The other choices establish scenarios that are either too late to effectively manage the pests or do not align with the principles of integrated pest management. For instance, waiting for total crop yield to decrease significantly or for pesticide costs to rise could lead to irreversible damage or reduced profitability. Similarly, addressing pest issues only when aesthetic damage becomes noticeable might result in pest populations escalating beyond manageable levels, leading to more severe economic repercussions.