USDA Develops a Method to Measure IPM Adoption

USDA Develops a Method to Measure IPM Adoption
By Dr. Charles Benbrook

In the months after the June, 1993 announcement of the Administration's 75 IPM percent IPM adoption goal, USDA and EPA officials were frequently asked where the nation's farmers currently stood relative to the goal. Lacking an empirical basis to answer such questions, senior USDA officials directed the Economic Research Service (ERS) to develop and apply a method to estimate current IPM adoption, and to complete the job sooner rather than later. The ERS report Adoption of IPM in U.S. Agriculture was released in September 1994 (Vandeman et al., 1994; see Pest Management at the Crossroads for references). Its stated purpose is to establish a baseline estimate of adoption of IPM for use in monitoring progress toward the Administration's 75 percent goal. The report's basic empirical finding is that --
      "IPM has been adopted on 50 percent or more of the crop acreage in the fruits and nuts, vegetables, and field crops studied for at least one of the three pest types: insects, diseases, and weeds."
IPM Adoption Criteria in the ERS Report The report includes separate measures of IPM adoption for weeds, insects and plant diseases. But for an acre to count as "under IPM", a farmer must have used an "IPM approach" in just one of these three areas of pest management. "An IPM approach" requires, at a minimum, scouting for a pest and a subsequent pesticide application in accord with some threshold. So, a farmer scouting for broadleaf weeds who makes a decision to apply a broadleaf herbicide on the basis of a threshold would be deemed managing pests under IPM regardless of how they manage other weeds, insects, or plant diseases. In the case of corn, the use of a crop rotation in combination with no use of soil insecticides is also deemed IPM, regardless of whether a field was scouted.
The report explains that IPM systems are highly variable and range from chemical dependent to biologically based, along what amounts to a continuum. The USDA chose to divide all farmers into four categories -- "No IPM", and three levels of IPM adoption: "Low", "Medium", and "High".
Simple rules were used in dividing pest management systems into "No IPM", and the three levels of IPM. The basic criterion was scouting and application in accord with economic thresholds. Curiously, an acre not sprayed with a pesticide was deemed not under IPM, since no pesticide was applied after scouting and according to a threshold. Farms producing crops with unusual or new pest problems where there are no established thresholds were not be counted, nor were many organic farms on which no synthetic pesticides were applied.
Acreage was judged as falling in the low, medium, and high levels of IPM based on the number of practices "indicative of an IPM approach". For each major category of pests – weeds, insects, plant diseases – and each major type of crop – fruits and nuts, vegetables, and field crops – the ERS identified 7 to 9 practices deemed "indicative of an IPM approach". The distribution of acres managed under varying levels of IPM systems was projected as follows:

"Low" level IPM requires only scouting (S) and pesticide applications in accord with thresholds (T) for one type of pest;

"Medium" level IPM requires S+T plus 1 or 2 additional practices from those identified as "indicative of an IPM Approach"; and
"High" level IPM, which requires S+T plus 3 or more additional practices.

Drawing on national cropping and chemical use surveys carried out in the last 5 years, ERS identified 24 practices "indicative of an IPM" approach: 8 in fruit and nut IPM; 9 in vegetable IPM; and, 7 in the production of field crops, all dealing with weed management. Of these 24 practices –

10 are part of all well-managed cropping systems and are adopted for several reasons in addition to increasing the effectiveness of pest management systems or reducing their cost;

8 are necessary either to cost-effectively apply pesticides or to extend the useful life of a pesticide active ingredient by slowing the emergence of resistance; and

only 6 are biologically-based preventive pest management practices that are commonly found on farms practicing, or moving toward biointensive IPM.

The box "Data Sources for Measuring Adoption of IPM" explains how ERS compiled a database to measure national IPM adoption. We used the same data-sets in our own estimates of IPM adoption presented further on.
1. Results of the ERS Study on IPM Adoption
ERS concluded that IPM was practiced on 50 percent or more of crop acreage in the early 1990s. Some 42 percent of fruit and nut producers did not use IPM, and another 8 percent were not classified as practicing IPM because they did not apply pesticides. This later group no doubt includes the majority of farmers producing fruits and nuts using organic production systems.
In the case of vegetable pest management, ERS projected IPM adoption by major class of pests. Figure 1 summarizes their findings. Insects were managed under IPM on about 52 percent of vegetable acreage; plant diseases, 41 percent. Only 1 percent of vegetable acres were considered under "High" level IPM in managing plant diseases, a concern given the frequency of fungicide residues found in some fresh and processed vegetable products (AMS, 1993; Wiles, 1993b).

Data Sources for Measuring Adoption of IPM
Researchers in the United States have extensive data on several major crops to draw upon in estimating IPM adoption. Despite shortcomings, ERS analysts deserve recognition for creativity in using cropping practices and pesticide use survey data compiled several years earlier for different purposes. Fruit and nut data came from a 1991 survey. Information on vegetable crops came from a 1992 survey, which included a follow-up survey on selected IPM practices done on a subset of farms. These practices were among those identified in 1994 as "indicative of an IPM approach". Data on field crops was derived from 1993 Cropping Practice Surveys, which collected considerable IPM practice data on a subset of field crops and states contained in the nationwide chemical use surveys.
In developing its methodology for measuring adoption of IPM at various levels, ERS was constrained by the supply and nature of data USDA compiles on pest management practices and systems through its various chemical use and cropping practices surveys. National information on IPM practices has only recently been collected, beginning in the early 1990s. Growing interest in IPM convinced ERS and the National Agricultural Statistics Service (NASS), the part of USDA which actually carries out field surveys, to add additional questions to existing surveys that had changed little over the years.
As a result of the steady increase in the number of pest management system questions, the database available to evaluate IPM systems is rapidly expanding. The 1995 and 1996 surveys will provide the richest data yet for the study of IPM system adoption and the consequences of IPM on pesticide use and reliance, and hence risk outcomes.
Figure 1:    IPM Adoption by Major Pest Type Along the IPM Continuum: USDA Estimates for Vegetable Production

Source: Derived from Adoption of IPM in U.S. Agriculture, ERS/USDA, 1994.
In general most but not all farmers who use scouting also apply pesticides in accord with thresholds. The report notes that "although 54 percent of apple acreage is professionally scouted, fulfilling the monitoring criteria for IPM, only 43 percent of apple acreage meets both the monitoring and threshold criteria for IPM." Similar differences were found in most other crops -- about 20 percent of the acreage scouted is sprayed without regard to thresholds.
Discouraging Insights from Crop by Crop Results       ERS estimated IPM adoption by individual crops, resulting in a number of surprising findings --

Over 55 percent of apple acreage was not scouted for any pests, likewise 53 percent of peaches, and across all fruit and nut crops studied, 35 percent of acreage was not scouted;

Not one of nine pest management practices "indicative of an IPM approach" were used on 17 percent of fruit and nut crop acreage;

60 percent or more of cabbage, green peas, and onion acreage was managed without IPM even though about two-thirds of the harvested acreage was sprayed with insecticides, herbicides and fungicides;

No IPM was used in managing pests on almost 30 percent of vegetable acreage; and

About 90 percent of vegetable acreage surveyed was not treated with any of 3 pest management practices typically found in biointensive systems.
Proven management practices that are essential components of all sound agronomic and IPM systems were not used on surprisingly large portions of planted acreage --

Resistant varieties were used on only 22 percent of fruit and nut acreage, and water management practices on 31 percent; and

Almost two-thirds of vegetable crop acreage was sprayed with pesticides without regard to impacts on beneficials.

A Synthesis of ERS/USDA Results on IPM Adoption       Based on the criteria chosen by ERS to measure adoption of IPM, we have synthesized the results reported in the 1994 ERS report across all crops and types of pests. We report our findings according to the four zones along the Consumer Union IPM continuum discussed in Chapter 7. In the next section, we discuss in more detail our own analysis and estimates of IPM adoption using criteria more firmly grounded in the ecological roots of IPM. But first, USDA's bottom-line. In the early 1990s of the roughly 50 percent of the acreage under one of three levels of IPM –

Between 5-15 percent was under low level IPM, pest management systems requiring just scouting and applications in accord with thresholds;

About 25-35 percent was under medium level IPM, requiring scouting and adherence to thresholds, plus 1-2 additional practices "indicative of an IPM approach"; and

About 20 to 30 percent was under high level IPM, scouting and applications in accord with thresholds, plus three or more practices "indicative of an IPM approach".
In addition, between 35 percent and 60 percent of crop acreage was judged as not under IPM by USDA because it was either not sprayed with pesticides, sprayed but not first scouted, or scouted and sprayed but not in accord to thresholds. This synthesis of the ERS report's basic findings is presented in Figure 2 below. The shaded area on the top of each bar reflects the ranges of acreage by zone in which most crops fall, taking into account differences across classes of pests.
Figure 2:    USDA Estimate of IPM Adoption: A Synthesis Across Crops and Types of Pests

* Lighter areas define ranges in values reported for different crops and classes of pests.
Source: Benbrook Consulting Services Analysis of Data in Adoption of IPM in U.S. Agriculture, ERS/USDA, 1994