Bioproducts are defined as naturally occurring living organisms (bacteria, fungi, nematodes, insects, plants, etc.) and extracts of living organisms, used to control pests and diseases, enhance growth of and protect plants and animals in indoor and outdoor environments.
Bioproducts basically fall into two categories – Biocontrol agents (or products) and Biostimulants.
Biological control – or biocontrol – is the use of living organisms, such as insects, or bacterial and fungal pathogens, to control pest populations. The main aim of biocontrol is not to completely eradicate the target organism, but to control it to such a level that it does not have an economic impact anymore. Biocontrol basically employs nature’s own mechanisms to ensure balance and equilibrium in the environment.
Biocontrol products can be extremely target specific. In the case of viruses, only the target is affected due to its extreme host specificity, thereby having no impact on other organisms in the environment. In many cases the biocontrol agents introduced into the environment are capable of sustaining themselves, often by reducing whatever pest population they are managing. This will however be at much lower levels than what is initially applied. It does mean that the control can be kept in place for a much longer time than other methods of pest control. Biocontrol is natural and doesn’t rely on the use of man-made chemicals that can adversely impact an ecosystem. It also allows the amount of chemical pesticide, required for control, to be reduced and is a powerful tool in preventing resistance from developing against a chemical pesticide when used in an integrated pest management program. Registered biocontrol products have gone through a rigorous screening process and no harmful products are registered. This means that biocontrol agents pose no threat to human health, crop production or beneficial organisms.
Kinds of biocontrol agents:
1.1 Parasitoids – an organism that spends a significant section of its life cycle attached to or inside a single host organism where the host is ultimately killed. Insects, nematodes, fungi, bacteria and viruses can fall in this category.
1.2 Predators – an organism that feeds on other organisms. Insects, mites, fungi, bacteria and nematodes can fall in this category.
1.3 Plant extracts – an extract of plant material that can kill or otherwise disrupt the life cycle of a pest to such an extent that it can no longer reproduce or cause damage.
1.4 Microbial extracts – an extract from microbial growth media that can kill or otherwise disrupt the life cycle of a pest to such an extent that it can no longer reproduce or cause damage.
1.5 Pheromones – chemicals naturally emitted by insects synthetically manufactured and used to disrupt the life cycle of the pest, or to eliminate the pest through trapping.
Biostimulants are products that stimulate natural processes in the plant or around the roots to enhance nutrient uptake, nutrient efficiency, increased tolerance to abiotic stress, and crop quality, vigour and yield. To summarise, biostimulants can have the following functions:
- Improving the efficiency of the plant’s metabolism to induce yield increases and enhanced crop quality.
- Increasing plant tolerance to and recovery from abiotic stress, like heat, cold, drought and waterlogging.
- Helping to improve nutrient-use efficiency (nutrient assimilation, translocation and use).
- Enhancing quality attributes of produce, including sugar, protein and oil content, colour, fruit seeding, as well as shelf-life of produce.
- Increasing the efficiency of water utilisation.
- Enhancing soil fertility.
Biostimulants work through different mechanisms than fertilisers do. They act only on the plant’s vigour and do not have any direct actions against pests or disease. Biostimulants are complementary to crop nutrition and crop protection products. Biostimulants have a significant contribution to make in ensuring food security and the sustainability of modern agriculture.
Kinds of biostimulants:
2.1 Microbial inoculants – bacteria, fungi or other organisms. Rhizobia (Symbiotic nitrogen fixers), free-living nitrogen fixers, phosphate solubilisers, etc. fall under this category.
2.2 Plant extracts – an extract of plant material. Seaweed extracts, carbohydrates, proteins, amino acids, and lipids, humic and fulvic acids all fall under this category.
2.3 Microbial extracts – an extract from microbial growth media. Certain amino acids, proteins and lipids fall under this category.