Time to rethink how to measure effectiveness of biocontrol products

July 2025

The effectiveness of conventional crop protection products such as pesticides has been historically measured by yield compared to untreated crops and percentage of pests killed. In modern times, measurement has shifted to crop damage, especially with the widespread adoption of Integrated Pest Management (IPM). But these measures cannot be applied in a copy-paste way to biocontrol products, nor do they capture some of the additional value offered by these products. 

Incidence and severity of a pest’s presence can also be measures of effectiveness but what matters more is how those factors impact a crop – in other words, crop damage. The mere presence of a pest doesn’t necessitate crop protection. But if the pest negatively impacts a crop to a certain level, it must be controlled. That often involves the use of crop protection products, whether conventional, biological or both. Of course, such products may also be used to prevent crop damage in the first place by keeping pests away or to inconsequential levels.  

Many biocontrol products focus on preventing damage by maintaining balanced populations of pests and their natural predators. Under real-world conditions, it is more difficult to determine the effectiveness of prevented damage because one cannot know exactly what would have happened without intervention. However, under test conditions, comparisons can be made between what happens with a certain biocontrol product versus a conventional control.  

 

How and what to measure for biocontrol product effectiveness?  

Starting from a blank page, various parameters should be considered to measure the effectiveness or value of biocontrol products more holistically. For example: 

• Can the biocontrol product reduce the use of other plant protection products that are more disruptive to the ecosystem?  

• How effectively does it control the pest as part of IPM involving other products or practices?

• How effective is the biocontrol product against a pest over a crop season or several seasons?

• How much does the biocontrol product expose handlers and users to potentially unwanted effects (or not)?

• Does it generate residues or does it break down completely and safely?

• What are the positive or negative impacts of the biocontrol product on the environment, such as impacts on soil health?

• Does it require a pre-harvest interval (wait time between application and when a crop can be harvested)?

• Does the biocontrol product help prevent pest resistance to another product?  

 

When evaluating all crop protection products, environmental merits and demerits are key factors for a broader concept of effectiveness beyond the direct effect on pests. For example, if a product effectively kills pests but also several other non-target organisms, its overall effectiveness is lower than another product with a similar performance, but less impact on non-target species. On the other hand, a product with a short waiting period between application and when farm workers can re-enter the field should have a higher overall score because it is less disruptive to on-farm activities. 

Given that most biocontrol products do not act the same or as quickly in the field as their conventional counterparts, it is important to have a more holistic view of effectiveness. For instance, biocontrol products generally have high target specificity and fast biodegradability. Other advantages include little or no impact on non-target organisms, low to no product residue and minimal risk to applicators, including quick re-entry and pre-harvest intervals.  

A more comprehensive and fit-for-purpose approach to measuring the effectiveness of biocontrol products would provide essential information farmers need to choose the best products for their circumstances.