Despite their significant distinctions, there is a lot of misunderstanding about the difference between biostimulants and biopesticides.   

We spoke with UPL’s technical specialist - Stuart Jackson - to get some clarity on the two product types, their intended use, and the key facts to remember. 

[video width="848" height="480" mp4="https://goodgrowingclub.co.uk/wp-content/uploads/2025/02/Biostimulants-vs-Biopesticides.mp4"][/video]  

Abiotic vs biotic symptoms 

One of the main differences between biostimulants and biopesticides is the types of symptoms they tackle.   

Biostimulants focus on abiotic symptoms in the plant, like drought stress.   

Biopesticides tackle biotic symptoms like disease and pest attacks.   

More generally, biostimulants are defined as substances or microorganisms that enhance plant growth by stimulating natural processes - such as nutrient uptake and stress tolerance. They don’t have a direct pesticidal effect.   

In contrast, biopesticides are specifically designed to target pests and control disease. They include microbial agents, plant extracts, and other natural substances. 

The laws and regulations of biostimulants vs pesticides 

By law, biopesticides must be registered as crop protection products.   

That means a full data package must be provided that demonstrates how any type of biopesticide product delivers on the claims it makes. They have to prove their efficacy.   

This is the same level of information and data that any traditional crop protection must share.   

In practice, what that means is that biopesticides must go through the same level of rigorous testing and trials as any other traditional pesticide. To get approval, the results must be clear.   

For biostimulants, in the UK at present there are no such regulations. These products don’t need to provide information or data.   

This situation may change as DEFRA (Department for Environment, Food & Rural Affairs) reviews potential regulations for biostimulants to align with EU standards post-Brexit. 

Key facts to remember about biostimulants vs biopesticides 

1. Biostimulants stimulate natural processes by targeting abiotic symptoms 
2. Biopesticides focus on biotic symptoms - like pest and disease attacks
3. If you want a crop protection product - you need a biopesticide 
4. Biopesticides are regulated like traditional pesticides - biostimulants are not
5. Because of the regulation, growers can trust the claimed efficacy of biopesticides

Do you have any more thoughts on biostimulants and biopesticides?