Which condition is necessary for a compound to be considered a pest?

For a compound to be considered a pest, it is essential that it causes economic harm. This criterion is foundational in the field of pest management, as the primary focus is on the impact that a pest has on crops, livestock, property, or human activities. Economic harm can manifest in various forms, such as reduced crop yields, increased costs for control measures, or damage to infrastructure. The significance lies in the direct financial implications that pests impose on individuals, businesses, and the broader economy.

Other factors, such as whether a species is non-native, its reproductive rate, or its potential harm to human health, can contribute to its classification as a pest but do not solely define it. For instance, a species could be native and still cause significant economic damage, making it a pest. Similarly, while rapid reproduction can enhance a species' pest status, it is the actual impact on economic aspects that solidifies this classification. Therefore, the necessity of economic harm is the defining characteristic for a compound to be considered a pest.