Simple Insect Control Model
Modeling of Agricultural Systems [AGS721]
LAB 6
Simple Insect Control Model
This exercise includes two interacted population of insect namely insect pest and beneficial insect. Given basic flow diagram of insect control model (see Jongkaewwattana, 1995 page 61) and the following information, re-draw causal-loop diagram and flowdiagram and formulate the model using PD Plus. Select your best strategies in controling the insect pest.
Insect Pest
1. The insect pest has four growth stages i.e. egg, larva, pupa, and adult.
Each stage proceeds through normal duration which are;
Duration of egg = 7 days Duration of pupa =
8 days
Duration of larva = 10 days Duration of adult
= 14 days
2. Egg has delay period of 10 days.
3. The deposit rate of eggs depend upon (number of adults x deposit fraction)
in which the deposit fraction also depend upon the number of adults given
as the following data;
| Adult # | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 |
| Fraction | 0.67 | 0.62 | 0.54 | 0.49 | 0.41 | 0.38 | 0.31 | 0.27 | 0.25 | 0.23 |
4. Insecticide (a) kills larva population which
each application can reduce 40% of larva population.
5. Insecticide (b) kills pupa population which each application can reduce
30% of larva population.
6. Insecticide (c) kills adults population which each application can reduce
60% of larva population.
Beneficial Insect
1. The beneficial insect has three growth stages i.e. egg, larva, 0.and
adult. Each stage proceeds through normal duration which are;
Duration of egg = 7 days Duration of pupa =
8 days
Duration of larva = 10 days Duration of adult = 14 days