The health of a plant is determined by its environment. This environment includes abiotic factors (i.e. sun, rain, wind and soil nutrients) and biotic factors (i.e. pests, diseases and weeds). All these factors can play a role in the balance, which exists between herbivore insects and their natural enemies. If we understand the whole system of interactions, we can use this knowledge to reduce the negative impact of pests and diseases.
Decision making in Integrated Pest Management requires a thorough analysis of the agro-ecosystem. Participants in IPM training will have to learn how to observe the crop, how to analyze the field situation and how to make the proper decisions for their crop management. This process is called the Agro-Eco-System Analysis (AESA).
AESA involves three steps
Observation → Analysis → Decision making
When participants of IPM training learn to do an agro-ecosystem analysis (AESA) they will make a drawing on a large piece of paper, in which they include all their observations. The advantage of using a drawing is that it forces the participants to observe closely and intensively. It is a focal point for the analysis and for the discussions that follow, and the drawing can be kept as a record.
AESA methodology
The following methodology is taken from a guide on IPM training where the participants were learning to do an AESA in rice. For other crops, the approach could be slightly different, but the basics are the same.
- Go to the field in groups. Walk across the field and choose 10 plants randomly. Observe keenly each of these plants and record your observations:
- Plant: observe the plant height, number of tillers, crop stage, deficiency symptoms, etc.
- Pests: observe and count pests at different places on the plant.
- Defenders: observe and count parasites and predators.
- Diseases: observe leaves and stems and identify any visible disease symptoms.
- Rats: count numbers of plants affected by rats.
- Weeds: observe weeds in the field and their intensity.
- Water: observe the water situation of the field.
- Weather: observe the weather condition.
- While walking in the field, manually collect insects in plastic bags. Use a sweep net to collect additional insects. Collect plant parts with disease symptoms.
- Find a shady place to sit as a group in a small circle for drawing and discussion.
- Kill the insects with some chloroform on a piece of cotton.
- Each group will first identify the pests, defenders and diseases collected.
- Each group will then analyze the field situation and present their analysis in a drawing (AESA drawing).
- Each drawing will show a plant/hill representing the field situation. The weather condition, water level, disease symptoms, etc. will be shown in the drawing. Pest insects will be drawn on the left. Defenders (beneficial insects) will be drawn on the right. Write the number next to each insect. Indicate the plant part where the pests and defenders were found. Try to show the interaction between pests and defenders.
- Each group will discuss the situation and make a recommendation.
- A member of each group will now present their analysis in front of all participants. Make sure that a different person will present each week.
- The facilitator will facilitate a discussion by asking guiding questions.
- The facilitator also makes sure that all participants (also shy persons or illiterate persons) become actively involved in this process.
- Formulate a common conclusion. The whole group should support the decision on what field management is required.
- Make sure that the required activities (based on the decision) will be carried out.
- Keep the drawing for comparison in the following weeks.
Some questions that can be used during the discussion
- Can you summarize the present situation of the field?
- What aspect is most important at this moment?
- Is there a big change with last week? What kind of change?
- Is there any serious pest or disease outbreak?
- What is the situation of the beneficial insects?
- Is there a balance in the field between pests and defenders?
- Where you able to identify all pests and diseases?
- Do you think the crop is healthy?
- What management practices are needed at this moment?
- When will it be done? Who will do it? Make sure that responsibilities for all activities are being discussed.
- Are you expecting any problems to emerge during the coming week? What problems? How can we avoid it? How can we be prepared?
- Can you summarize the actions to be taken?
