June 13, 1998

Saturday
Breakout Sessions

1. Dealing with resistance; we know that we will lose tools; how do we encourage diversity in tools and in cropping systems?

2. How do we incorporate cultural practices knowing there is resistance? How do we incorporate farm by farm decision making (outreach programs by users, extension)?

• Need to think about simplification regarding measurement tools.
• The more diverse the ecosystem becomes, the less chance there is for resistance.
• Use on regular basis - sustainable with diverse systems.
• EPA: maybe ask about different possible tools, rank in terms of tools leading to data base, can then take pesticide use and show that a particular system generates more resistance with consistent pesticide use.
• Next Step: management of the system that is preventative in nature to other management and cropping systems.
• Challenge farmers and farm decision makers to think about diversity of tactics to manage resistance. Use a Diversity Index for use for farmers and specialists.

• Need to define Diversity: Diversity has a temporal element, a waiting element and a spatial element (We should use resilience rather than resistance).
• Bio-based systems - need redundancy and need to incorporate control mechanisms which are different from chemical control, e.g. spraying pesticide and the particular pest is basically gone.
• Need to be proactive; we cannot wait until the system fails.

• Diversity Index - development and measurement are key functions. (example was given by Eric Hesketh: it is like financial management which entails portfolio diversification to avoid losing money).
• Use summary statistics to evaluate diversity. The hypothesis is such that when the diversity index decreases, problems are emerging. This leads to the task of evaluating the methods in order to attain efficiency in the system.
• Points out where vulnerability of the system is present.
• Need the same strategies across the board (weeds, diseases, pests).

• The problem becomes how to evaluate systems in terms of environmental impact? Need to attach weights which are essentially points for preventative practices. It is a relative rating of diversity.
• Apply in principle Chuck Benbrook's IPM Continuum.
• A generic pesticide on one side of the continuum and farm practices on the other side of the continuum with expert judgement in terms of reliance on pesticides, experts come up with rating system. Would include variable such like those used in USLE but would also include temporal variables.

Challenge: Relate Monitoring and Thresholds =>

1. First threshold: indicates need to tweak the management system.
2. Second threshold: indicates management system failed.
   both items become part of resistance.

Question: How do you know the difference between 1.) and 2.)?
Answer: Field monitoring; system is more robust if extensive monitoring is in place.

1. Prevention (cultural, mechanical, and sanitary methods, introduction of beneficial)
2. Avoidance (crop rotation)
3. Monitoring
4. Suppression
   0-~ tactics under each item

PAMS	Insects	Weeds	Diseases
Prevention
Avoidance
Monitoring
Suppression

Score Card

WHY RESILIENCE INDEX???
Can measure over time
Identify potential and real problems

- the more crop and management diversity tactics, the more points are assigned

• Strategies have to be agreed upon
  • Regions, environments, etc.
  • Develop theoretical diversity index, i.e. different index for each crop.
  • Measure and monitor over time

1. Operationalize PAMS diversity index - a measure of IPM resilience.
2. Apply in corn and soybeans, pilot projects to field test PAMS. - Can test retroactively against corn rootworm problem.

Notes & concepts as organized by Lois Levitan

Challenge/Questions:
How can factors other than pesticide toxicity and exposure (application factors + fate and transport) be incorporated into IPM risk indicators/assessment systems?

I.e., How can an assessment capture the environmental impacts of such factors as a pest's potential to develop resistance to a control method (whether control is from a pesticide or a cultural practice)?

IPM is dealing with pest resistance in an atmosphere where practitioners are losing pest control tools. How can this factor (potential for development of resistance) be conceptually integrated into IPM assessment systems? (Either as a stand-alone indicator or integrated into measurement systems designed primarily to register relative toxic risk of pesticides.)

Since resistance itself might be considered a feedback to the IPM system, rather than an impact, in and of itself,

When (for what types of indicators/assessment systems) is it appropriate to include such a measure?

I.e., If the question is to assess trends in toxic exposure, it may not be relevant. However, if the question is to assess best practices or to determine resilience of an IPM system, then an assessment that only considers toxic risk and not resistance potential (or other impacts of cultural practices) may give misleading results.

Approach:
Create an index to predict resistance potential of a pest, as a function of selection pressure. The indicator is roughly based on the diversity of practices used to control the pest.

It should not be based simply on the number of options available to control a given pest, but should also consider:

• the intensity of adoption of a specific control practice (borrow from ecological measures of species richness)-one or more 'intensity' coefficients may be used to capture spatial diversity, temporal diversity, and numerical diversity.

• duration of use of a given practice. The thinking behind this is that if a practice is used continuously over time, its efficacy is likely to decrease over time

• the complexity of the resistance: how many different genes come into play in the development of the resistance. Thought: cultural practices may call more genes into play than do chemical practices

• relate the practice to some measure of cost to pest control manager (i.e., farmer, but also others) and its efficacy in controlling the pest.

  [Lois Note: Are these factors relevant only an indicators of likelihood of adoption, or do they play another role as well? If they are an indicator of the likelihood of adoption, perhaps incorporate via a weighting factor for efficacy, or by a composite weight reflecting the several factors influencing adoption-including efficacy at controlling pest, cost, off-target negative impacts, hassle (which may include labor time, knowledge required), etc.?]

[Lois Note: If the indicator is to be used to assess the fragility of an IPM system (i.e.-the likelihood of resistance buildup), then the key issue may be the diversity of pest control practices that are used. e.g., in the corn-soy system described by MG, the practices were seemingly either (1) constant corn, using pesticides to control corn rootworm-which was not considered an IPM system, or (2) the corn-soy rotation, with no pesticides used to control the rootworm-which was recommended as an IPM practice.

If, however, the indicator is to be used to assess research priorities in IPM, or to assess success of IPM research programs, then perhaps the key may be the diversity of pest control practices that are available. Here then the next step may be assessing barriers to adoption of available IPM methods that are not being used.]

Objective of the Indicator:
To determine a diversity threshold, below which resistance potential is low. i.e., how high/low a score do you need before resistance takes infinity to develop?

Possible Structure of the Indicator:
Sum of F_i,

where F= the fraction of decrease of a pest within a regional cropping (or management) system and i = a given 'resistance avoidance' factor or pest control practice.

Question: How many i's are significant?

Note: Volkmar Gutsche brought a handout for an indicator which includes some of the same criteria and factors discussed here. See Burth et al. "Proposal for an indicator to measure the adoption of IPM in a farm (arable crops)."

Issues:
Does diversity of pest control practices of necessity cost more?

How much diversity is good, and how does diversity relate to predator/parasite population?

Approach can be applied to farm decision-making as well as policy. [Lois Note: but with perhaps different twist-as noted above]

Because good management strategies, esp. those designed to decrease resistance potential, often involve a multi-year time horizon, the indicator must also consider pest control practices over multiple years. (Appropriate number of years is probably the number for the full rotation of practices.)

For example, in order to reduce resistance potential, pest control managers may periodically use a more toxic pesticide in rotation with pesticides less toxic to non-target organisms (NTOs).

Notes from Harold Coble Report: For diversity index, identify four types of pest control strategies: prevention, avoidance, monitoring, suppression (PAMS), each of which may have a number of tactics. Can measure over time and identify when the system might get into trouble.

Group Discussion:

• In the Pre-FQPA era, there were 10 times the factors for cumulative risk as a common mode of mechanism. Project identification was the point over FQPA factors for the organophosphates' cholinesterase mode of action. That's what was responsible for FQPA factor. They set up committee. For the cumulative risk the common mode of action is cholinesterase action. Forty chemicals are analyzed at this point. There are some really good data bases as well as some really bad ones. Some pesticides were cancelled because data was not in the data base for some reason and we need to figure out how to put the data in. Does the Act designate some level of safety to shoot for or are we going to derive that? What is the target? What is the endpoint? If they de-register pesticides, can we make decisions on one or all of the reviews? Endpoints are mixed between toxicology and exposure. Even cumulative exposure is breaking the envelope. We need an assessment warning systems; and we need to deal with the potential impacts of non-pesticidal pest management practices.

• The market effects of different practices that were adopted in tart cherries is an example. If there is broad resistance to a practice, what would be the ultimate effect? In a region-wide level we have to have an idea of what all producers are doing. IPM is important to get program administration to look at trends.

• The dwarfing of apple trees is something else. One third of orchards are using smaller trees. The cultural technique is to calibrate the trees. We are also dealing with new plantation densities. In New York we still have a mix of trees, but there is also a concern over old orchards that are refuges for pests. We saw dwarfing of trees as a system that could lead to less pesticide use. In the next ten years, vulnerability in our system is going to be discovered. We have major problems in the rootstock of the trees as well as susceptibility to windstorms. Maybe cultural practices are not such a big plus as previously seen. In both this case and in corn/soybean rotations, the people weren't stupid or unconcerned about it. They were just not able to come up with risk assessment with hindsight. What was unexpected was the thought that the solution would last forever, but it had no feedback mechanism. And climate change can change the whole model.

• After the Dutch Elm Disease hit, people were planting honey locusts. The basic concept is "don't put all your eggs in one basket," now the question is how to monitor. We need mechanisms to say what is the hazard of doing "xyz." Everybody is trying to put it all into the same system. It is very hard to compare apples to soybean. There is a rotation but not of same type. It is a conceptual product.

• Think about assessment systems as factors, i.e. resistance and cultural factors and how might we integrate them to come up with a couple of solutions. I see the way clear to get beyond pesticide use. However, we have to stay away from sustainability.

• Should we clarify only risk assessment, or also measurement systems which measure the degree of IPM? How do we give scores to farmers as amount of IPM?

• We have to think about various tools we can adapt to take into account different factors. We need to consider both evaluation tools and policy evaluation tools for farmers. We must get more precise about risk.

• Whatever pest management system you put out there - it will fail.

• What we want out of this is not a system or any system. We have to make ourselves think better about assessment systems, both the potentials and the limitations.

• So the conclusion is that trying to figure out pesticide exposure is only one part.

• We have to broaden our thinking to resistant factors as well as cultural factors.

• Measuring sustainability is not only on a farm level, it is also on a landscape level. Should we assess only risk or the degree of IPM adoption? So should we do both risk assessment and IPM? Ask the question: does farmer have rotations or not.

• We could combine a score system with the risk assessment system.

• Regardless of resistance, the system has to be adjusted. That is a given.

• IFM (Integrated Fruit Management): What is feedback system there? What do you do to monitor and manage crops and adapt to the need to segregate thinking?

• We measure success over the last years as the lower amount of hazardous pesticides. We do not need organophosphates anymore in apple production, only in emergencies. We reduced the amount of pesticides by 2/3. We learned to control weeds just in June. We have trees that direct their energies into producing fruit, not more growth. There are no aphids. We actually have many parameters to measure the system.

• Aphids will adapt and not need so much nitrogen to develop. Is there something that shows that the biological system has changed? Will control then be use of another cultivar?

• We were alerted by fruit drop. It requires much more monitoring and continuous feedback.

• You can tell growers what to do. They must write it down in their farm books and field books. We must show that tactics can be listed on a point system, like a checklist. Monitoring is in the center of system.

• Joe's demonstration project shows success in cooperation. Feedback is voluntary.

• We have to have a driver. The EPA will make registration decisions not to preserve environment as much as to maintain their livelihood.

• Farmers must adopt practices before they sell their crops. They must provide information at the farm level. And the registrant needs to supply monitoring information.

• In some areas we can have a quasi-regulatory system, e.g. prescription use of pesticides in California.

• Pheremone disruption is done in Germany and in Washington state. On a state by state basis we need many more control tactics.

• We have to think seriously about other techniques. We need assessment tools to track resistance. How can we value or assign weights to non-pesticidal factors?

• IPM programs in some crops are at a dead end, especially with soybean and corn. We have to have to think about what to bring into system now, such as alfalfa rotation, etc.

• Mono-cultural systems can develop difficult problems depending on how widespread the practice is. It is not the particular tactic that leads to development of resistance but the amount and percentage of use. We need to know the percent of acres under any given strategy. We want measurements of the diversity of practices.

• There are a number of options in measuring intensity.

• It is not the number of alternatives but the intensity of application. Intensity is related to efficacy. And it is not how many possibilities there are but how many are practical.

• What about an equation which indicates species richness?

• We really don't want to get into a situation were diversity is gone. We need a way to rank, measure or rate diversity.

• The whole deal is that we want to avoid resistance.

• If we are creating an indicator of intensity, that shows us where to devote resources. But how many are good? Do we need to have diversity?

• When insect populations start to increase, pheromones are used to disrupt the mating system. When the number of predators are going down, then you have a problem.

• Biological and non-chemical treatments are not sufficient by themselves. They fail if the population is high, just like in the case of the coddling moth. We have to monitor the population. With a depressed population of coddling moth, we put in confusion technique. Implementation was successfully accomplished by farmers because they went into other things, e.g. they started to monitor: green (disruption), yellow (one application) and red (two applications). We have to figure out the scale.

• We would have to translate that to millions of acres in corn and soybean. We shouldn't be spraying without knowing what is going on in the fields.

• The best information is simply that farmers do not want to waste money. Are we coming close to what kind of factors to put into a formula to measure resistance potential?

• Efficacy factors, ecology richness, production costs, diversity.

• There is a possibility of outbreaks of secondary pests. We need diversity of different practices.

• IPM is fundamentally resistance management. We try to reduce environmental risk while maintaining profitability.

• Practice x reduces pest population by y. It is multiplicative or additive if we are assuming a linear response. The question of how many x's do you have.

• If we deal with a disrupter and another chemical, it would be codependent.

• I would do it by issue or pest crop and pest. Or it would be pest by pest and crop by crop. N equals different strategies. They must be applied to the region as well as to individual score.

• For the success of IPM, doesn't it need to be a regional approach?

• That depends on how unique the area is. The reason that there are lots of problems is the lack of buy-in from farmers.

• We have to design a measure to illustrate high diversity. High diversity represents a system that is more resistant to outbreaks.

• In terms of resistance models: They ought to be able to say that if they score "x" number it will take "x" number of years before resistance shows up.

• But it is not only a problem of resistance. From the farmers' perspective, we have to ask what they can grow and how is the market? Ask what pest problems do we have now, and can we come in with another crop? From the farmers' side, it becomes much more complicated. It depends on the market situation before it becomes a valid solution.

• We have to make sure the efficacy of the practice is good in and of itself as well as good for society. It is a mix of population biology and social transfer payments.

• The way I see we need to figure out how to use a diversity index to communicate how badly needed region-wide diversification of pest management is.

• We have to go to legislators. We need greater investment of resources, a toolkit. We can show that more diversity leads to fewer ecological problems.

• What can we use to impact payment programs? Can we use existing cost-share programs and make them more attractive?

• EQIP has buffers built into the cost-share program.

• One of problems with Mike's system is using it forever. Every year they used it, they thought the problems would diminish. If you use the same tactics every year (corn/soybean rotation) the program will fail. It is a matter of intensity and duration.

• We could use a population dynamics model. We need to account for use over so many years. It is probabilistic if a random change occurs and results in more resistivity because there is no pattern. It is a chaotic point of view. It is going to take a modeler.

• Still there is the possibility for selection.

• There is a lot of variability in attenuation. We are dealing with different numbers of genes involved. Also, it is a communication job because farmers think that the silver bullet will be there. We just know that the system will fail, not particularly what has failed in the system. It takes behavioral modifications by farmers and a different pattern of tactics.

• We've got to eat something along the way.

• I don't understand the actual biology of the pest, but entomologists do. Farmers understand attenuated resistance.

• Even with high diversity within field, if they use the same practices year after year, resistance might develop. We'll need spatial and temporal diversity as well as practices diversity. We need preventative practices. Farmers are asking "what does IPM really do for me?"

• We can develop measures such as a point system for everything that can be related to IPM and establish moving targets of what is minimal for IPM systems. This entails a lot of things that aren't control practices.

• What has an effect in trying to come up with parameter of resistance avoidance? The introduction of IPM pushed it. If we talk about IPM as a system, it has to evolve all the time. If we are looking for less hazardous chemicals we must demand new products. The main issue is human health, not the environment. Insect growth regulators are excellent tools for IPM. We need alternative products or practices.

• For a lot of things, we do have a fast track, but we are looking for alternatives (such as soil pathogens).

• Environmentally sound systems are less toxic and the tools need to be stronger ones. We court disaster if we kick all opportunities out.

• The Europeans show us that we can't throw everything out.

• Is it true for annuals as well as perennials? It is too cold for corn, i.e. corn for silage. There, we have problems with herbicides, not insecticides.

Therefore, we have:

Sum of F:

	n
F=	FThreshold
i=	1

where: F = the fraction of decrease of a pest within a regional cropping (or management) system and i = a given 'resistance avoidance' factor or pest control practice.

• temporal diversity
• spatial diversity
• practice diversity

Project/Program Evaluation

Does the New Zealand apple scheme score pesticides for resistance risk? No
Two tools:

1. Estimate/measure pesticide environmental impact as an evaluation tool.
2. Tools which help farmers reduce pesticide use as a management tool.

How frequently does one have to repeat a practice?
mode of action and how pesticides and other practices are used

• IPM Measurement Systems are more appropriate to manage resistance problems which allow experts to blend all tactics.
  • Measuring outcomes,
  • Measuring practices,
  • Can use resistance management as a separate analysis,

Resistance management is an agronomic problem
    Environmental impact rating
    Environmental risk
    Resistance factors

Pesticide Decisions are based on:

1. Effectiveness
2. Cost
3. Effects on predators and parasites
4. Resistance management

Incentives for Innovation:

1. Crisis - lose fewer possibilities for innovation
2. Subsidies, taxes, regulation

Conclusion:
Most IPM evaluation systems currently use point systems, not decision tools. We need tools which reduce the impacts of pesticides and have a positive impact on IPM.

General Discussion:

• One needs to know the questions before choosing specific endpoints. The goal of an indicator depends on whether we are talking site specific or general.

• - Environmental Impact Assessments measure risk. We can't forget that health risk depends on both exposure from and toxicity of the pesticide. If the ranking is conducted only on the basis of the pesticide itself, it could lead to a possible ban of the pesticide even though it might not pose a risk to humans in certain situations regardless if it is highly toxic.