Assessment of Sweet Corn IPM Adoption in New England & Mid-Atlantic States: Are We There Yet?
By C.S. Hollingsworth, W.M. Coli and B.A. Szala
Abstract
Questionnaires regarding general farming practices and specific IPM practices, were sent to 1318 farmers purported to grow sweet corn in seven states (CT, DE, ME, MD, MA, NJ, PA). A total of 832 questionnaires (63%) were returned: 502 respondents grew sweet corn. The response rate (17%) allows statistical inference at the 95% confidence level, with a sampling error of +/- 5%.
Adoption of IPM-related practices by respondents is summarized, for example: 82% reported application of pesticides to sweet corn; 76% calibrate sprayers annually or more often; 30% use pheromone or blacklight traps; 37% use university-provided pest thresholds.
Respondents' adoption of a comprehensive IPM system was measured using the elements and point system from the Massachusetts Crop-Specific IPM Definitions. Of the sweet corn growers surveyed, only 3% attained 70% of the possible IPM practice points, the requirement for IPM certification in Massachusetts. Thus, if this measurement of high-level IPM adoption is used, the federal goal of 75% of U.S. crop acreage under IPM appears distant.
Introduction
The government's goal is 75% of US crop acreage under IPM by the year 2000. ARE WE THERE YET?
Methods
We took a survey.
The Survey
The Dillman Total Design Method (Dillman 1978; Salant and Dillman 1994) was used to carry out the survey. Key conceptual elements of the method include: showing regard for the opinions of the respondent, making the questionnaire interesting and brief and establishing trust by identifying with a legitimate or known organization or group. Multiple mailings of questionnaire and reminders are used to improve response. In order for growers in each state to be contacted by a person they knew, all cover letters were printed on letterhead of the state's land grant, and signed by the state lead person.
The questionnaire was designed to determine adoption of specific pest and nutrient management practices by northeastern sweet corn growers. State collaborators participated in several revisions of the instrument.
Mailing lists were obtained from participating state vegetable extension lists and participants were selected by random number. Our intent was to sample a sufficiently large subset of the sweet corn grower population in seven states to provide a 95% confidence interval with a sampling error within 5%. Sample size was based on the assumption that individuals in the population are likely to vary in their use of or attitudes to IPM practices. A total of 1,318 farmers were contacted. Questionnaires were sent to entire mailing lists of the smaller states. Response rates were sufficient for our targeted confidence interval (Salant and Dillman 1994).
Analysis
Survey data were compiled to reflect differences in adoption of specific IPM practices and differences in adoption among states. To measure growers' adoption of a comprehensive IPM program, we adapted the Massachusetts Crop Specific IPM Definitions (Hollingsworth et al 1996). In this system, points are assigned to specific practices, based on their importance to the IPM system and their difficulty. In Massachusetts IPM certification projects, 70% of the possible IPM practice points are considered the minimum.
Results & Discussion
Response to the Survey
Survey of sweet corn IPM practices in northeastern states: response
| |
CT |
DE |
DE |
MD |
ME |
NJ |
PA |
Total |
| Questionnaires sent |
103 |
27 |
146 |
300 |
136 |
203 |
403 |
1318 |
| Valid surveys returned |
35 |
18 |
72 |
67 |
50 |
129 |
131 |
502 |
| % returned |
34% |
67% |
49% |
22% |
37% |
64% |
33% |
39% |
Adoption of IPM
Adoption of specific IPM practices varies among states. We suspect that variation is strongly influenced by university extension recommendations. Selection of certain IPM practices, e.g. selection of blacklight traps or pheromone traps, is clearly determined by local research and extension activities. Acceptance of certain IPM practices will be influenced by their costs of implementation. Simple field scouting and the use of disease resistant cultivars are examples of low cost methods which are widely implemented. Growers' acceptance of more sophisticated practices, i.e. pre-sidedress nitrogen testing and use of B.t., is likely a reflection of extension efforts in educating growers.
Percent adoption of insect management practices in northeastern states
| |
CT |
DE |
MA |
MD |
ME |
NJ |
PA |
Total |
| Weekly pest scouting |
85 |
94 |
82 |
72 |
49 |
71 |
62 |
71 |
| Treatment based on action thresholds |
48 |
71 |
51 |
31 |
28 |
47 |
19 |
38 |
| Plow under stubble for ECB1 control |
52 |
59 |
70 |
56 |
83 |
60 |
58 |
62 |
| Biological insecticide (B.t.) |
16 |
6 |
37 |
25 |
23 |
17 |
18 |
22 |
| Field monitoring for ECB |
71 |
83 |
82 |
58 |
70 |
76 |
47 |
66 |
| Pheromone Trap for ECB |
14 |
5 |
38 |
9 |
29 |
2 |
5 |
12 |
| Blacklight for ECB |
3 |
22 |
1 |
13 |
0 |
47 |
2 |
15 |
| Pheromone trap for CEW2 |
48 |
0 |
39 |
12 |
20 |
1 |
8 |
15 |
| Blacklight trap for CEW |
0 |
17 |
1 |
15 |
0 |
47 |
2 |
15 |
| Pheromone trap for FAW3 |
23 |
0 |
33 |
4 |
16 |
2 |
8 |
11 |
| Blacklight for FAW |
0 |
17 |
1 |
15 |
0 |
41 |
1 |
14 |
| Note: 1ECB, European Corn Borer 2CEW, Corn Earworm 3FAW, Fall Armyworm |
Adoption of IPM Practices by Northeast Sweet Corn Growers
Soil and Nutrient Management
| At least 75% of corn acreage rotated annually. |
28% |
| Fields evaluated annually with a soil test for nutrient status and pH within one year. |
36% |
| A pre-sidedress nitrate test taken. |
4% |
| Cover crop is planted to at least 75% of the corn acreage. |
51% |
Pesticide Application
| Pesticide sprayers calibrated at least once per season. |
76% |
| All corn stubble on farm turned under or harrowed before ECB flight. |
62% |
| A boom sprayer with drop nozzles used where coverage of the ear zone is desirable. |
24% |
| Pesticide coverage of target area and non-target area tested using water- sensitive spray cards. |
8% |
Insect Management
| Pheromone or blacklight traps used for corn earworm. |
30% |
| Pheromone or blacklight traps used for fall armyworm. |
25% |
| Pheromone or blacklight traps used for European corn borer. |
29% |
| Field monitoring for European corn borer. |
66% |
| Insecticide applications for pest lepidoptera correspond to state university specified thresholds. |
38% |
| Biological insecticide (B.t.) used. |
22% |
Weed Management
| Weeds monitored annually |
60% |
| Weeds controlled by cultivation, with no herbicide applied. |
11% |
| Herbicide rates reduced through banding of herbicides and cultivation |
7% |
| Herbicide use reduced through delayed application of reduced rates of herbicide. |
16% |
Disease Management
| Disease resistant cultivars planted |
84% |
Measuring adoption of a comprehensive IPM program
The Massachusetts IPM definition provides a comprehensive measure of IPM adoption, including nutrient, soil, insect, weed and disease management. Ninety-seven percent of northeastern sweet corn growers do not meet requirements needed for state IPM certification in Massachusetts. It is significant that the Massachusetts IPM certification program, Partners with Nature, certifies 15% of the total sweet corn acreage in Massachusetts, within the range of IPM adoption estimated by this survey. There higher rate of IPM adoption by Massachusetts growers in this survey suggests that IPM certification programs could enhance IPM adoption.
 |
Adoption of 70% (194 points) of the possible IPM practice points is considered the minimum for adoption of a comprehensive IPM program.
|
Assessment of sweet corn IPM adoption in northeastern states
| |
CT |
DE |
MA |
MD |
ME |
NJ |
PA |
Total |
| Median IPM score (number of points) |
115 |
161 |
111 |
87 |
87 |
117 |
72 |
92 |
| Median IPM score (percent of possible) |
40% |
56% |
39% |
31% |
31% |
41% |
25% |
32% |
| Percent of growers scoring > 70% of possible score |
3% |
6% |
11% |
2% |
3% |
1% |
0% |
3% |
Conclusion
Our data suggest that we are not there yet!
Acknowledgments
We thank the following researchers for assistance in developing and conducting the survey:
Jude Boucher
University of Connecticut |
Vern Grubinger
University of Vermont |
Galen Dively
University of Maryland |
Ruth Hazzard
University of Massachusetts |
Shelby Fleischer
Pennsylvania State University |
Donald Prostak
Rutgers University |
Eleanor Groden
University of Maine |
Joann Whalen
University of Delaware |
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