A Method to Measure the Environmental Impact of Pesticides
EIQ Field Use Rating
Once an EIQ value has been established for the active ingredient of each pesticide, field use calculations can begin. To accurately compare pesticides and pest management strategies, the dose, the formulation or percent active ingredient of the product, and the frequency of application of each pesticide need to be determined. To account for different formulations of the same active ingredient and different use patterns, a simple equation called the EIQ Field Use Rating was developed. This rating is calculated by multiplying the EIQ value for the specific chemical obtained in the tables by the percent active ingredient in the formulation by the rate per acre used (usually in pints or pounds of formulated product).
EIQ Field Use Rating = EIQ x % active ingredient x Rate
With this method, comparisons of environmental impact between pesticides and different pest management programs can be made. For example, if several pesticides can be used against a particular pest, which pesticide is the least toxic choice? Table 5 shows an example comparing the environmental impact of three insecticides: carbaryl (Sevin 50WP), endosulfan (Thiodan 50WP), and azinphos-methyl (Guthion 35WP). Although carbaryl has a lower EIQ (22.6) than endosulfan (40.5) or azinphos-methyl (43.1), it may take more of it to provide equivalent control. For example, 6 lbs/acre of Sevin may provide the same level of control of a certain pest as 3 lbs/acre of Thiodan or 2.2 lbs/acre of Guthion. In this situation, Guthion would have the lowest EIQ Field Use Rating (33 .2) and would be the least toxic choice. Thiodan (60.8) would be the second choice and Sevin (67.8) would be the last.
By applying the EIQ Field Use Rating, comparisons can be made between different pest management strategies or programs. To compare different pest management programs, EIQ Field Use Ratings and number of applications throughout the season are determined for each pesticide. and these values are then summed to determine the total seasonal environmental impact of the particular strategy. Table 6 compares the theoretical environmental impact of several different pest management approaches that have been used in research projects to grow 'Red Delicious' apples in New York. In this example, a traditional pest management approach to growing 'Red Delicious' apples that does not rely heavily on pest monitoring methods would result in a total theoretical environmental impact of 938 due to pesticides. An IPM approach that incorporates pest monitoring methods, biological control, and least toxic pesticides would have an environmental impact of only 167. The organic pest management approach, which uses only naturally occurring pesticides, would have a theoretical environmental impact of 1,799 according to the model. The environmental impact of the latter approach is so much larger than the other strategies primarily due to the larger quantities of sulfur required and more frequent applications needed to provide the same level of control of apple scab in this variety. By using the EIQ model, it becomes possible for IPM practitioners to rapidly estimate the environmental impact of different pesticides and pest management programs before they are applied, resulting in more environmentally sensitive pest management programs being implemented.
Table 3. An example showing the EIQ field use rating of three different insecticides to determine which pesticide should be the least toxic choice.
|
Material |
EIQ |
ai |
Rate |
EIQ field use rating |
|
Sevin 50WP (carbaryl) |
22.6 |
0.50 |
6.0 |
67.8 |
|
Thiodan 50WP (endosulfan) |
40.5 |
0.50 |
3.0 |
60.8 |
|
Guthion 35WP (azinphos-methyl) |
43.1 |
0.35 |
2.2 |
33.2 |
Table 4. Theoretical environmental impact of different pest management strategies used to grow 'Red Delicious' apples in New York.
|
Traditional Pest Management Strategy |
|||||
|
Material |
EIQ |
ai |
Dose |
Applications |
Total |
|
Rubigan EC |
27.3 |
0.12 |
0.6 |
4 |
8 |
|
Captan 50WP |
28.6 |
0.50 |
3.0 |
6 |
257 |
|
Lorsban 50WP |
52.8 |
0.50 |
3.0 |
2 |
158 |
|
Thiodan 50WP |
40.5 |
0.50 |
3.0 |
2 |
61 |
|
Guthion 35WP |
43.1 |
0.35 |
2.2 |
2 |
66 |
|
Cygon 4E |
74.0 |
0.43 |
2.0 |
3 |
191 |
|
Omite 6EC |
42.7 |
0.68 |
2.0 |
2 |
116 |
|
Kelthane 35WP |
29.9 |
0.35 |
4.5 |
1 |
47 |
|
Sevin 50WP |
22.6 |
0.50 |
1.0 |
3 |
34 |
|
Total Environmental Impact |
938 |
||||
|
Integrated Pest Management (IPM) Strategy |
|||||
|
Material |
EIQ |
ai |
Dose |
Applications |
Total |
|
Nova 40WP |
41.2 |
0.40 |
0.3 |
4 |
20 |
|
Captan 50WP |
28.6 |
0.50 |
3.0 |
1 |
43 |
|
Dipel 2X |
13.5 |
0.06 |
1.5 |
3 |
4 |
|
Sevin 50WP |
22.6 |
0.50 |
3.0 |
1 |
34 |
|
Guthion 35WP |
43.1 |
0.35 |
2.2 |
2 |
66 |
|
Total Environmental Impact |
167 |
||||
|
Organic Pest Management Strategy |
|||||
|
Material |
EIQ |
ai |
Dose |
Applications |
Total |
|
Sulfur |
45.5 |
0.90 |
6 |
7 |
1720 |
|
Rotenone/pyrethrin |
25.5 |
0.04 |
12 |
6 |
73 |
|
Ryania |
55.3 |
0.001 |
58 |
2 |
6 |
|
Total Environmental Impact |
1720 |
||||