Washington Horticultural Association

95th Annual Meeting Dec. 8, 1999, Wenatchee, WA

The concept of “areawide control” has a long history from initial quarantine eradication programs up to the current USDA-sponsored “areawide IPM” (Integrated Pest Management) projects. This “areawide control” concept generally means that a specific “key pest” is targeted throughout a defined region, on all managed and unmanaged (e. g. homeowners) property. The USDA-sponsored Codling Moth Areawide Management Program (CAMP) has just completed five seasons in five initial pome-fruit growing regions located in Washington, Oregon and California. At this time, with regard to program evaluation, we can ask questions like “What factors contribute to a successful areawide IPM implementation program?”, “How well did it work with CAMP?”, “Will the knowledge and methods of pest management that were developed continue to expand to more growers?”, and “Can any insights and successes be applied to other regions and for other commodities? While these questions may be difficult to answer, we will make some effort to address them here.

The Areawide IPM Codling moth program was the first of four such 5-year programs supported on a large scale by the USDA (Table 1). The concept of “areawide IPM” is actually a synthesis of two long standing approaches to pest control (Kogan 1995). The first, “areawide suppression and eradication”, was developed by the USDA under supervision of E. F. Knipling, from experience and theory relating to “genetic control” technologies, and has principally been successful against invasive, non-native species (Knipling 1979). Nearly all of such programs to date shared the characteristics that large contiguous areas were managed, participation was mandatory for growers within a program region, and that eradication or suppression of usually a single species was the objective. Since 1968, a large program in cotton in southern California has attempted eradication and IPM of pink bollworm and cotton pests. Similarly, the boll weevil eradication program in many of the cotton growing states was started in 1977. The red imported fire ant now occupies over 275 million acres in the US, making this eradication project an example of a complete failure, in part due to a reliance on chemicals for control. The screwworm eradication program, based on sterile insect releases (SIR), has been a major success, with ongoing efforts to eradicate the flies from Central America after successes in the southern US (1966) and Mexico (1991). Ongoing eradication programs in the US include boll weevil and witchweed (USDA-APHIS 1999). The concepts of “pest eradication” and “genetic control” have historically occupied a small niche in the overall theory and practice of pest management (Metcalf and Luckman 1994).

Table 1. Current 5-year areawide IPM programs funded by USDA:

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System		Region	      1st year  Target Pest         Main Tactic(s)
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Apple & pear    WA, OR, CA	1995	Codling moth        Mating disruption, SIR
Corn		Midwest		1996	Corn rootworm	    Bait and kill
Rangeland	MT, WY, SD, ND	1997	Leafy spurge weed   Flea beetle biocontrol
Stored grain	KS, OK		1997	Stored grain pests  Sanitation, early aeration
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Source: USDA/ARS reports
Nov 1999 Yakima, WA.

IPM attempts to integrate and harmonize all control methods to provide the least damage to the environment while supporting the growers’ need to remain competitive. With the understanding that eradication of native or well established species may be an unreasonable if not impossible objective, many large scale, IPM-based programs have been supported by USDA since the 1970's. These programs, which usually included a regional (but not necessarily contiguous-area) focus for implementation, depended upon growers to participate voluntarily and to make their own pest control decisions. In Oregon alone, there have been USDA-sponsored IPM implementation projects targeting snap beans, peppermint, filberts, and seed crops during the 1970's and 1980's. Although these USDA IPM programs were terminated, the need to address IPM implementation from a broad, regional perspective has remained. The areawide codling moth IPM program was conceived as a synthesis of the areawide suppression and IPM programs (Kogan 1994). This “areawide IPM” approach includes both a major emphasis placed on the key pest(s), while accepting that IPM must be an integrated systems approach to pest management, also dealing with secondary pests. By key pest, we mean a pest that nearly always causes economic damage if left unchecked. By secondary pest, we mean a pest that normally does not cause economic damage unless naturally occuring biological control is disrupted by pesticides. Today we have many alternatives to conventional pesticides, which are in general much more “selective” to the target organism, and are much “softer” on the environment. In the absence of selective controls for the key pest, secondary pests can become greater economic pest problems than are the key pests. This situation is well known in pear, for example, where a few low cost sprays for codling moth can cause secondary outbreaks of pear psylla and spider mites, which then require much more expensive treatments, whereas they should otherwise be adequately controlled by their predators in the orchard.

The areawide IPM concept has been proposed as a synthesis between areawide suppression and classical IPM. The case for an areawide IPM approach arises if 1) the key pest(s) may be adequately controlled using selective, non-disruptive, or “soft” methods, 2) a regional, contiguous area, rather than local, implementation would benefit effectiveness of such selective pest control tactic(s), and 3) Adequate incentives exist for growers to cooperate on at least some aspects of pest sampling and decision making, such as by sharing monitoring data and adopting standard control guidelines. Examples of selective tactics that benefit from an areawide approach include mass releases of sterile insects or biological control agents, destruction of non-crop alternate hosts and refugia, mating disruption using pheromone saturation, and combinations of such tactics (Kogan 1995).

The factors that may have contributed to the general success of the CAMP have been addressed widely at this conference and as outlined in the original conceptual plan (Kogan 1994). Some of these factors are listed in Table 2.

Table 2. Factors contributing to the success of the areawide codling moth program, 1995-1999.

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1. Wide availability of an effective new technology (mating disruption) that 
has major benefits resulting from a regional approach to implementation.
2. A well organized, coordinated approach with full support of growers, the tree 
fruit industry, USDA administration and researchers, and University research
and extension personnel.
3. Decision making by both program coordinators and individual growers.
4. Incentives for grower participation in the form of limited subsidies and 
monitoring and managerial support.
5. Availability of other selective controls for outbreaks of secondary and 
minor pests [with some exceptions].
6. Involvement of applied researchers able to provide technical support and 
adapt quickly to changing conditions.
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We will refer to these characteristics as a desireable model for other potential areawide programs later on.

We now take a look at the adoption rate of mating disruption and whether this rate may have been impacted by the CAMP program. A fundamental trend significant to both population growth and to the adoption of new technologies is the cumulative normal or “logistic growth” curve (Fig. 1). Unchecked populations, such as the codling moth (or even humans), for example, tend to struggle at very low levels (Fig. 1; Region A) until an exponential (or logarithmic) phase of growth (Region B) is achieved. The leveling off phase (Region C), occurs only when resources become scarce, such as when the apple crop is nearly 100% infested by codling moth. The reason why mating disruption has been successful, is that as long as insecticides or other controls are used initially to kill off, say, 90% of the population, then the remaining low levels are controlled because the pheromone prevents the males from finding the last few females. This explains why some of the more isolated areawide regions have reported a 98+% reduction in total codling moth trap catch from 1995 to 1999 [e. g. Howard Flat and Oroville, as presented Nov 18-19, Yakima areawide codling meetings]. Given that codling moth has limited ability to migrate significant distances, brief local extinctions are possible. However, complete eradication of codling moth from a large region is beyond the funding and logistical capacity of the CAMP program.

Figure 1. The growth curve, used to describe both the growth of populations and the adoption of new technologies.

In British Columbia, Canada, where sterile insect release (SIR), mating disruption, and other tactics were used to attempt codling moth eradication, that goal was recently determined to be unrealistic and has been replaced with the goal of taking an IPM approach. But as mating disruption has been successful for low level population control, and large contiguous areas are treated, then codling moth can be considered to be “controlled” below economically damaging levels from an areawide or regional perspective.

The same curve in Fig. 1 also applies to the adoption of new technologies, and can be used to describe the benefits of the areawide IPM approach. The level of adoption of mating disruption for codling moth in Washington was less than 1% in 1991. With the extra support and publicity provided through the (CAMP) program, including a full time extension specialist for two years, adoption in Washington rose to 15% in 1996 and to 30-35% in 1999, for all apple and pear acreage (Table 3).

Table 3. Adoption of codling moth mating disruption by apple and pear growers in CAMP programs and in Washington State.

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                Areawide only	Total use of mating disruption - WA
	Year	acresa 		acres		% of total acreage
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	1991	-		1,500 		0.8%
	1995	3,000		18,000		9%
	1996 	3,000		25,000		15%
	1999	20,000		75,000		30-35%
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 a including acres in WA, OR, and CA
Sources: Gut et al. 1996; Areawide reports, Yakima 1999.