Principles of non-chemical pest management
The successful use of non-chemical pest management builds on various pillars. In reality, activities directed towards non-chemical pest management use specific pillars as entry points with various degrees of links between them for reasons of practicality. A remaining challenge is to integrate the key pillars of the diverse approaches to non-chemical pest management in a way that they support each other and create the best possible impact.
Key pillars for non-chemical pest management
Government policy, expressed by their framework concerning education, research, agricultural training and extension, pesticide regulation, budgetary priorities etc. strongly determines the dissemination, use and adoption of non-chemical pest management strategies. Progress is most likely under a national IPM programme that effectively integrates community-based field activities, policy, extension and research. PAN has a strong background in promoting such policies. OISAT Info
is a tool offering technical support which could easily be integrated into national research, training and extension programmes.
A variety of economic factors influence the success of non-chemical pest management strategies. Pesticide subsidies are known to lead to a decision-making at farm level in favor of pesticides because they lower the cost compared to other practices. Often, credit is linked to the purchase of chemical inputs. The externalization of costs associated with pesticide use, which should favor the promotion of non-chemical pest management, has been amply documented.
Education, training, extension and knowledge generation
Non-chemical crop protection approaches are generally knowledge intensive pest management systems. Today we have a comprehensive understanding of the principles of learning to manage pests using a systems approach. This understanding has yet to be translated into strategies and approaches comprising community-based field activities, policy, extension and research as mentioned under policy framework. To date, there is also a number of private sector driven programs applying such comprehensive approaches.
The most important sources of technical solutions are research, indigenous knowledge and innovations generated through farmer participatory research. Today, a host of technical information exists. Part of this information is stored in research reports and technical documents, part of it can be found on the internet. For the interested user in the field, all this information is still scattered and it can be time-consuming to compile needed information. OISAT Info
attempts to systematize available technical information in a form that corresponds with the mind frame and logic of farmers. By organizing information in such a way, we hope to be able to contribute to getting all this valuable information come to life.
Key principles and concepts of non-chemical pest management
In this section, the key principles and concepts of non-chemical pest management, stemming from a conceptual understanding as a form of applied ecology, are presented at a general level. Detailed and pest-specific information is presented in OISAT Info
under "Preventive control" and "Curative control" for each pest described.
Working towards technical solutions, the following three categories of information comprise the key principles and concepts of non-chemical pest management:
Basic know how
Know your pests and natural enemies
The accurate identification of the species, life cycle, habitat requirements, time and location of occurrence, damage pattern, susceptible time for control form an important part of the knowledge of pests and natural enemies and are indispensable for a successful long-term pest management strategy.
Inspection, monitoring, record-keeping and decision-making for protection
Monitoring is the systematic scouting of crops for pests and natural enemies, either regularly or at susceptible times to understand if the self-regulatory regulation of pests is still intact or if additional measures need to be taken.
The methods for monitoring differ from pest to pest. It is important to know for each pest when to monitor, the proper method and possibly what tools to use. Typical aids for monitoring are sweep nets, sticky traps, and pheromone traps.
Climate and weather conditions also influence the pest activity and rate of reproduction. Knowledge of these can help to predict the likelihood of disease infections and thus aid in the designing of appropriate preventive measures.
Preventive pest management
The most important preventive pest management strategies are:
Removing infested plant material including crop residues from the field reduces carryover of pests from one planting to the next and thus prevents reinfestation.
Generally cultural practices contribute to the "belowground biodiversity" with the help of healthy and biologically actives soils. They contribute to "aboveground biodiversity" by providing a habitat for diverse natural enemies. Furthermore, cultural practices contribute to suppressing pest build-up by disrupting the normal relationship between the pest and the host plant and thus make the pest less likely to survive, grow, or reproduce. Common cultural practices include crop rotation, tillage, varying timing of planting or harvesting, planting trap crops, adjusting row width, healthy organic soils, cultivating suitable varieties.
Enhancing natural enemies
These are stimulated by various intercropping schemes, the integration of insectary plants, etc. By creating farming systems which are high in biodiversity, the self-regulatory mechanisms are increased and the system tends to be more "dynamically stable". This means that the variety of organisms provide more checks and balances on each other, which helps prevent one species (i.e., pest species) from building up a population level that causes economic damage. The major categories of natural enemies are predators, parasitoids, pathogens and some vertebrates such as birds, snakes.
Curative pest management
Curative pest management practices should be used in an integrated manner and consider potential side effects on human health, the environment, the sustainability of the agricultural system and the economy.
A number of natural products can be used in curative pest management. Some general traits of plants used in pest control and other natural products include the following:
Plant extracts used for pest control degrade rapidly in sunlight, air, and moisture, and by detoxification enzymes. Rapid breakdown means less persistence and reduced risks to non-target organisms. However, precise timing and/or more frequent applications may be necessary.
Some plants in pest control are also used as medicinal plants, others may have low to moderate mammalian toxicity, and some are highly toxic (e.g., nicotine). They can express acute toxicity or cause chronic to sub-chronic effects on human health. Therefore, information on side effects and toxicity are important and will be included in OISAT as much as we have access to such information. During processing and application they should be handled with the same caution as synthetic pesticides. Plants in pest control are most effective when used in an integrated pest management (IPM) program, which includes sanitation, cultural practices, mechanical controls, use of resistant plant varieties, and biological control among others.
The rapid break down and fast action make botanicals more selective to certain plant-feeding pests and less harmful to beneficial insects.
Most plants used in pest control are non-phytotoxic. However, insecticidal soaps, sulfur, and nicotine sulfate may be toxic to some vegetables or ornamentals.
Cost and Availability
Plants used in pest control tend to be more expensive than synthetics, and some are not produced in a great supply or are no longer commercially available (e.g., nicotine). The potency of some botanicals may vary from one source or batch to the next.
In OISAT Info, the curative methods presented are categorized into four groups:
- Plants in pest control
Plants used in pest control should ideally possess the following characteristics:
- Be effective at a rate of max. 3-5% plant material based on dry weight
- Be easy to grow and require little space and time for cultivation or procurement
- Recover quickly after the material is harvested
- Be perennial
- Not become a weed or a host to plant pathogens or insect pests
- Possess complementary economic uses
- Pose no hazard to non-target organisms, wildlife, humans or the environment
- Be easy to harvest; preparation should be simple, not too time-consuming or require too high a technical input
- Applications should not be phytotoxic or decrease the quality of a crop, e.g. taste or texture.
- Other substances
Soaps, oils and mineral substances are presented under this category.
- Physical methods
The physical methods encompass different types of methods used to control pests or alter their environment. Traps, screens, barriers, fences, nets etc. can be used to prevent the spread of pests into an area.
- Other methods
Under this category, methods are presented which do not belong to any of the other categories.